id stringlengths 24 24 | title stringclasses 442
values | context stringlengths 151 3.71k | question stringlengths 12 270 | answers dict |
|---|---|---|---|---|
59d29da22763a6001828410f | Great_Plains | The 100th meridian roughly corresponds with the line that divides the Great Plains into an area that receive 20 inches (510 millimetres) or more of rainfall per year and an area that receives less than 20 in (510 mm). In this context, the High Plains, as well as Southern Alberta, south-western Saskatchewan and Eastern Montana are mainly semi hot steppe land and are generally characterised by rangeland or marginal farmland. The region (especially the High Plains) is periodically subjected to extended periods of drought; high winds in the region may then generate devastating dust storms. The eastern Great Plains near the eastern boundary falls in the humid subtropical climate zone in the southern areas, and the northern and central areas fall in the humid continental climate. | What Canadian province lies north of the Great Plains? | {
"answer_start": [],
"text": []
} |
59d29da22763a60018284110 | Great_Plains | The 100th meridian roughly corresponds with the line that divides the Great Plains into an area that receive 20 inches (510 millimetres) or more of rainfall per year and an area that receives less than 20 in (510 mm). In this context, the High Plains, as well as Southern Alberta, south-western Saskatchewan and Eastern Montana are mainly semi hot steppe land and are generally characterised by rangeland or marginal farmland. The region (especially the High Plains) is periodically subjected to extended periods of drought; high winds in the region may then generate devastating dust storms. The eastern Great Plains near the eastern boundary falls in the humid subtropical climate zone in the southern areas, and the northern and central areas fall in the humid continental climate. | What would be a state that lies east of the Great Plains? | {
"answer_start": [],
"text": []
} |
59d29da22763a60018284111 | Great_Plains | The 100th meridian roughly corresponds with the line that divides the Great Plains into an area that receive 20 inches (510 millimetres) or more of rainfall per year and an area that receives less than 20 in (510 mm). In this context, the High Plains, as well as Southern Alberta, south-western Saskatchewan and Eastern Montana are mainly semi hot steppe land and are generally characterised by rangeland or marginal farmland. The region (especially the High Plains) is periodically subjected to extended periods of drought; high winds in the region may then generate devastating dust storms. The eastern Great Plains near the eastern boundary falls in the humid subtropical climate zone in the southern areas, and the northern and central areas fall in the humid continental climate. | What meridian comprises the northern edge of the Great Plains? | {
"answer_start": [],
"text": []
} |
59d29da22763a60018284112 | Great_Plains | The 100th meridian roughly corresponds with the line that divides the Great Plains into an area that receive 20 inches (510 millimetres) or more of rainfall per year and an area that receives less than 20 in (510 mm). In this context, the High Plains, as well as Southern Alberta, south-western Saskatchewan and Eastern Montana are mainly semi hot steppe land and are generally characterised by rangeland or marginal farmland. The region (especially the High Plains) is periodically subjected to extended periods of drought; high winds in the region may then generate devastating dust storms. The eastern Great Plains near the eastern boundary falls in the humid subtropical climate zone in the southern areas, and the northern and central areas fall in the humid continental climate. | What meridian comprises the southern edge of the Great Plains? | {
"answer_start": [],
"text": []
} |
59d29da22763a60018284113 | Great_Plains | The 100th meridian roughly corresponds with the line that divides the Great Plains into an area that receive 20 inches (510 millimetres) or more of rainfall per year and an area that receives less than 20 in (510 mm). In this context, the High Plains, as well as Southern Alberta, south-western Saskatchewan and Eastern Montana are mainly semi hot steppe land and are generally characterised by rangeland or marginal farmland. The region (especially the High Plains) is periodically subjected to extended periods of drought; high winds in the region may then generate devastating dust storms. The eastern Great Plains near the eastern boundary falls in the humid subtropical climate zone in the southern areas, and the northern and central areas fall in the humid continental climate. | How much rain does Northern Alberta get every year? | {
"answer_start": [],
"text": []
} |
570b690bec8fbc190045b9f8 | Great_Plains | After 1870, the new railroads across the Plains brought hunters who killed off almost all the bison for their hides. The railroads offered attractive packages of land and transportation to European farmers, who rushed to settle the land. They (and Americans as well) also took advantage of the homestead laws to obtain free farms. Land speculators and local boosters identified many potential towns, and those reached by the railroad had a chance, while the others became ghost towns. In Kansas, for example, nearly 5000 towns were mapped out, but by 1970 only 617 were actually operating. In the mid-20th century, closeness to an interstate exchange determined whether a town would flourish or struggle for business. | after about what year did railroads bring hunters to the great plains? | {
"answer_start": [
6
],
"text": [
"1870"
]
} |
570b690bec8fbc190045b9f9 | Great_Plains | After 1870, the new railroads across the Plains brought hunters who killed off almost all the bison for their hides. The railroads offered attractive packages of land and transportation to European farmers, who rushed to settle the land. They (and Americans as well) also took advantage of the homestead laws to obtain free farms. Land speculators and local boosters identified many potential towns, and those reached by the railroad had a chance, while the others became ghost towns. In Kansas, for example, nearly 5000 towns were mapped out, but by 1970 only 617 were actually operating. In the mid-20th century, closeness to an interstate exchange determined whether a town would flourish or struggle for business. | what animal did hunters kill off for their hides? | {
"answer_start": [
94
],
"text": [
"bison"
]
} |
570b690bec8fbc190045b9fa | Great_Plains | After 1870, the new railroads across the Plains brought hunters who killed off almost all the bison for their hides. The railroads offered attractive packages of land and transportation to European farmers, who rushed to settle the land. They (and Americans as well) also took advantage of the homestead laws to obtain free farms. Land speculators and local boosters identified many potential towns, and those reached by the railroad had a chance, while the others became ghost towns. In Kansas, for example, nearly 5000 towns were mapped out, but by 1970 only 617 were actually operating. In the mid-20th century, closeness to an interstate exchange determined whether a town would flourish or struggle for business. | what farmers rushed in to settle the land with the help of the railroads? | {
"answer_start": [
189
],
"text": [
"European farmers"
]
} |
570b690bec8fbc190045b9fb | Great_Plains | After 1870, the new railroads across the Plains brought hunters who killed off almost all the bison for their hides. The railroads offered attractive packages of land and transportation to European farmers, who rushed to settle the land. They (and Americans as well) also took advantage of the homestead laws to obtain free farms. Land speculators and local boosters identified many potential towns, and those reached by the railroad had a chance, while the others became ghost towns. In Kansas, for example, nearly 5000 towns were mapped out, but by 1970 only 617 were actually operating. In the mid-20th century, closeness to an interstate exchange determined whether a town would flourish or struggle for business. | what did the railroads offer the farmers that rushed in to settle the area? | {
"answer_start": [
150
],
"text": [
"packages of land and transportation"
]
} |
59d29f642763a60018284123 | Great_Plains | After 1870, the new railroads across the Plains brought hunters who killed off almost all the bison for their hides. The railroads offered attractive packages of land and transportation to European farmers, who rushed to settle the land. They (and Americans as well) also took advantage of the homestead laws to obtain free farms. Land speculators and local boosters identified many potential towns, and those reached by the railroad had a chance, while the others became ghost towns. In Kansas, for example, nearly 5000 towns were mapped out, but by 1970 only 617 were actually operating. In the mid-20th century, closeness to an interstate exchange determined whether a town would flourish or struggle for business. | In what year were the homestead laws passed? | {
"answer_start": [],
"text": []
} |
59d29f642763a60018284124 | Great_Plains | After 1870, the new railroads across the Plains brought hunters who killed off almost all the bison for their hides. The railroads offered attractive packages of land and transportation to European farmers, who rushed to settle the land. They (and Americans as well) also took advantage of the homestead laws to obtain free farms. Land speculators and local boosters identified many potential towns, and those reached by the railroad had a chance, while the others became ghost towns. In Kansas, for example, nearly 5000 towns were mapped out, but by 1970 only 617 were actually operating. In the mid-20th century, closeness to an interstate exchange determined whether a town would flourish or struggle for business. | How many towns existed in Kansas in 1950? | {
"answer_start": [],
"text": []
} |
59d29f642763a60018284125 | Great_Plains | After 1870, the new railroads across the Plains brought hunters who killed off almost all the bison for their hides. The railroads offered attractive packages of land and transportation to European farmers, who rushed to settle the land. They (and Americans as well) also took advantage of the homestead laws to obtain free farms. Land speculators and local boosters identified many potential towns, and those reached by the railroad had a chance, while the others became ghost towns. In Kansas, for example, nearly 5000 towns were mapped out, but by 1970 only 617 were actually operating. In the mid-20th century, closeness to an interstate exchange determined whether a town would flourish or struggle for business. | How many free farms were doled out overall? | {
"answer_start": [],
"text": []
} |
59d29f642763a60018284126 | Great_Plains | After 1870, the new railroads across the Plains brought hunters who killed off almost all the bison for their hides. The railroads offered attractive packages of land and transportation to European farmers, who rushed to settle the land. They (and Americans as well) also took advantage of the homestead laws to obtain free farms. Land speculators and local boosters identified many potential towns, and those reached by the railroad had a chance, while the others became ghost towns. In Kansas, for example, nearly 5000 towns were mapped out, but by 1970 only 617 were actually operating. In the mid-20th century, closeness to an interstate exchange determined whether a town would flourish or struggle for business. | How many cities existed in Kansas as of 2000? | {
"answer_start": [],
"text": []
} |
59d29f642763a60018284127 | Great_Plains | After 1870, the new railroads across the Plains brought hunters who killed off almost all the bison for their hides. The railroads offered attractive packages of land and transportation to European farmers, who rushed to settle the land. They (and Americans as well) also took advantage of the homestead laws to obtain free farms. Land speculators and local boosters identified many potential towns, and those reached by the railroad had a chance, while the others became ghost towns. In Kansas, for example, nearly 5000 towns were mapped out, but by 1970 only 617 were actually operating. In the mid-20th century, closeness to an interstate exchange determined whether a town would flourish or struggle for business. | How many bison were killed for their hides? | {
"answer_start": [],
"text": []
} |
570b8145ec8fbc190045ba3c | Great_Plains | The rural Plains have lost a third of their population since 1920. Several hundred thousand square miles (several hundred thousand square kilometers) of the Great Plains have fewer than 6 inhabitants per square mile (2.3 inhabitants per square kilometer)—the density standard Frederick Jackson Turner used to declare the American frontier "closed" in 1893. Many have fewer than 2 inhabitants per square mile (0.77 inhabitants per square kilometer). There are more than 6,000 ghost towns in the state of Kansas alone, according to Kansas historian Daniel Fitzgerald. This problem is often exacerbated by the consolidation of farms and the difficulty of attracting modern industry to the region. In addition, the smaller school-age population has forced the consolidation of school districts and the closure of high schools in some communities. The continuing population loss has led some to suggest that the current use of the drier parts of the Great Plains is not sustainable, and there has been a proposal - the "Buffalo Commons" - to return approximately 139,000 square miles (360,000 km2) of these drier parts to native prairie land. | how much of the population have the rural plains lost since 1920? | {
"answer_start": [
27
],
"text": [
"a third"
]
} |
570b8145ec8fbc190045ba3d | Great_Plains | The rural Plains have lost a third of their population since 1920. Several hundred thousand square miles (several hundred thousand square kilometers) of the Great Plains have fewer than 6 inhabitants per square mile (2.3 inhabitants per square kilometer)—the density standard Frederick Jackson Turner used to declare the American frontier "closed" in 1893. Many have fewer than 2 inhabitants per square mile (0.77 inhabitants per square kilometer). There are more than 6,000 ghost towns in the state of Kansas alone, according to Kansas historian Daniel Fitzgerald. This problem is often exacerbated by the consolidation of farms and the difficulty of attracting modern industry to the region. In addition, the smaller school-age population has forced the consolidation of school districts and the closure of high schools in some communities. The continuing population loss has led some to suggest that the current use of the drier parts of the Great Plains is not sustainable, and there has been a proposal - the "Buffalo Commons" - to return approximately 139,000 square miles (360,000 km2) of these drier parts to native prairie land. | who declated the American frontier "closed" in 1893? | {
"answer_start": [
276
],
"text": [
"Frederick Jackson Turner"
]
} |
570b8145ec8fbc190045ba3e | Great_Plains | The rural Plains have lost a third of their population since 1920. Several hundred thousand square miles (several hundred thousand square kilometers) of the Great Plains have fewer than 6 inhabitants per square mile (2.3 inhabitants per square kilometer)—the density standard Frederick Jackson Turner used to declare the American frontier "closed" in 1893. Many have fewer than 2 inhabitants per square mile (0.77 inhabitants per square kilometer). There are more than 6,000 ghost towns in the state of Kansas alone, according to Kansas historian Daniel Fitzgerald. This problem is often exacerbated by the consolidation of farms and the difficulty of attracting modern industry to the region. In addition, the smaller school-age population has forced the consolidation of school districts and the closure of high schools in some communities. The continuing population loss has led some to suggest that the current use of the drier parts of the Great Plains is not sustainable, and there has been a proposal - the "Buffalo Commons" - to return approximately 139,000 square miles (360,000 km2) of these drier parts to native prairie land. | how many ghost towns are in the state of Kansas? | {
"answer_start": [
459
],
"text": [
"more than 6,000"
]
} |
570b8145ec8fbc190045ba3f | Great_Plains | The rural Plains have lost a third of their population since 1920. Several hundred thousand square miles (several hundred thousand square kilometers) of the Great Plains have fewer than 6 inhabitants per square mile (2.3 inhabitants per square kilometer)—the density standard Frederick Jackson Turner used to declare the American frontier "closed" in 1893. Many have fewer than 2 inhabitants per square mile (0.77 inhabitants per square kilometer). There are more than 6,000 ghost towns in the state of Kansas alone, according to Kansas historian Daniel Fitzgerald. This problem is often exacerbated by the consolidation of farms and the difficulty of attracting modern industry to the region. In addition, the smaller school-age population has forced the consolidation of school districts and the closure of high schools in some communities. The continuing population loss has led some to suggest that the current use of the drier parts of the Great Plains is not sustainable, and there has been a proposal - the "Buffalo Commons" - to return approximately 139,000 square miles (360,000 km2) of these drier parts to native prairie land. | how much prarie land does the "Buffalo Commons" want to return? | {
"answer_start": [
1058
],
"text": [
"139,000 square miles"
]
} |
59d2a5782763a6001828415b | Great_Plains | The rural Plains have lost a third of their population since 1920. Several hundred thousand square miles (several hundred thousand square kilometers) of the Great Plains have fewer than 6 inhabitants per square mile (2.3 inhabitants per square kilometer)—the density standard Frederick Jackson Turner used to declare the American frontier "closed" in 1893. Many have fewer than 2 inhabitants per square mile (0.77 inhabitants per square kilometer). There are more than 6,000 ghost towns in the state of Kansas alone, according to Kansas historian Daniel Fitzgerald. This problem is often exacerbated by the consolidation of farms and the difficulty of attracting modern industry to the region. In addition, the smaller school-age population has forced the consolidation of school districts and the closure of high schools in some communities. The continuing population loss has led some to suggest that the current use of the drier parts of the Great Plains is not sustainable, and there has been a proposal - the "Buffalo Commons" - to return approximately 139,000 square miles (360,000 km2) of these drier parts to native prairie land. | How many people lives per square mile on the Great Plains in 1900? | {
"answer_start": [],
"text": []
} |
59d2a5782763a6001828415c | Great_Plains | The rural Plains have lost a third of their population since 1920. Several hundred thousand square miles (several hundred thousand square kilometers) of the Great Plains have fewer than 6 inhabitants per square mile (2.3 inhabitants per square kilometer)—the density standard Frederick Jackson Turner used to declare the American frontier "closed" in 1893. Many have fewer than 2 inhabitants per square mile (0.77 inhabitants per square kilometer). There are more than 6,000 ghost towns in the state of Kansas alone, according to Kansas historian Daniel Fitzgerald. This problem is often exacerbated by the consolidation of farms and the difficulty of attracting modern industry to the region. In addition, the smaller school-age population has forced the consolidation of school districts and the closure of high schools in some communities. The continuing population loss has led some to suggest that the current use of the drier parts of the Great Plains is not sustainable, and there has been a proposal - the "Buffalo Commons" - to return approximately 139,000 square miles (360,000 km2) of these drier parts to native prairie land. | In what year was the Great Plains considered "open" to inhabitants and farm activity? | {
"answer_start": [],
"text": []
} |
59d2a5782763a6001828415d | Great_Plains | The rural Plains have lost a third of their population since 1920. Several hundred thousand square miles (several hundred thousand square kilometers) of the Great Plains have fewer than 6 inhabitants per square mile (2.3 inhabitants per square kilometer)—the density standard Frederick Jackson Turner used to declare the American frontier "closed" in 1893. Many have fewer than 2 inhabitants per square mile (0.77 inhabitants per square kilometer). There are more than 6,000 ghost towns in the state of Kansas alone, according to Kansas historian Daniel Fitzgerald. This problem is often exacerbated by the consolidation of farms and the difficulty of attracting modern industry to the region. In addition, the smaller school-age population has forced the consolidation of school districts and the closure of high schools in some communities. The continuing population loss has led some to suggest that the current use of the drier parts of the Great Plains is not sustainable, and there has been a proposal - the "Buffalo Commons" - to return approximately 139,000 square miles (360,000 km2) of these drier parts to native prairie land. | What's the school-age population of Kansas? | {
"answer_start": [],
"text": []
} |
59d2a5782763a6001828415e | Great_Plains | The rural Plains have lost a third of their population since 1920. Several hundred thousand square miles (several hundred thousand square kilometers) of the Great Plains have fewer than 6 inhabitants per square mile (2.3 inhabitants per square kilometer)—the density standard Frederick Jackson Turner used to declare the American frontier "closed" in 1893. Many have fewer than 2 inhabitants per square mile (0.77 inhabitants per square kilometer). There are more than 6,000 ghost towns in the state of Kansas alone, according to Kansas historian Daniel Fitzgerald. This problem is often exacerbated by the consolidation of farms and the difficulty of attracting modern industry to the region. In addition, the smaller school-age population has forced the consolidation of school districts and the closure of high schools in some communities. The continuing population loss has led some to suggest that the current use of the drier parts of the Great Plains is not sustainable, and there has been a proposal - the "Buffalo Commons" - to return approximately 139,000 square miles (360,000 km2) of these drier parts to native prairie land. | In what year was the "Buffalo Commons" proposal made? | {
"answer_start": [],
"text": []
} |
59d2a5782763a6001828415f | Great_Plains | The rural Plains have lost a third of their population since 1920. Several hundred thousand square miles (several hundred thousand square kilometers) of the Great Plains have fewer than 6 inhabitants per square mile (2.3 inhabitants per square kilometer)—the density standard Frederick Jackson Turner used to declare the American frontier "closed" in 1893. Many have fewer than 2 inhabitants per square mile (0.77 inhabitants per square kilometer). There are more than 6,000 ghost towns in the state of Kansas alone, according to Kansas historian Daniel Fitzgerald. This problem is often exacerbated by the consolidation of farms and the difficulty of attracting modern industry to the region. In addition, the smaller school-age population has forced the consolidation of school districts and the closure of high schools in some communities. The continuing population loss has led some to suggest that the current use of the drier parts of the Great Plains is not sustainable, and there has been a proposal - the "Buffalo Commons" - to return approximately 139,000 square miles (360,000 km2) of these drier parts to native prairie land. | How many high schools remain in Kansas? | {
"answer_start": [],
"text": []
} |
570b819cec8fbc190045ba44 | Great_Plains | Although the eastern image of farm life in the prairies emphasized the isolation of the lonely farmer and wife, plains residents created busy social lives for themselves. They often sponsored activities that combined work, food and entertainment such as barn raisings, corn huskings, quilting bees, Grange meetings, church activities and school functions. Women organized shared meals and potluck events, as well as extended visits between families. The Grange was a nationwide farmers' organization, they reserved high offices for women, and gave them a voice in public affairs. | who usually organized shared meals and potluck events? | {
"answer_start": [
356
],
"text": [
"Women"
]
} |
59d2a3ad2763a6001828414b | Great_Plains | Although the eastern image of farm life in the prairies emphasized the isolation of the lonely farmer and wife, plains residents created busy social lives for themselves. They often sponsored activities that combined work, food and entertainment such as barn raisings, corn huskings, quilting bees, Grange meetings, church activities and school functions. Women organized shared meals and potluck events, as well as extended visits between families. The Grange was a nationwide farmers' organization, they reserved high offices for women, and gave them a voice in public affairs. | Who presided over church activities in the Great Plains? | {
"answer_start": [],
"text": []
} |
59d2a3ad2763a6001828414c | Great_Plains | Although the eastern image of farm life in the prairies emphasized the isolation of the lonely farmer and wife, plains residents created busy social lives for themselves. They often sponsored activities that combined work, food and entertainment such as barn raisings, corn huskings, quilting bees, Grange meetings, church activities and school functions. Women organized shared meals and potluck events, as well as extended visits between families. The Grange was a nationwide farmers' organization, they reserved high offices for women, and gave them a voice in public affairs. | Who did barn raisings at farm on the Great Plains? | {
"answer_start": [],
"text": []
} |
59d2a3ad2763a6001828414d | Great_Plains | Although the eastern image of farm life in the prairies emphasized the isolation of the lonely farmer and wife, plains residents created busy social lives for themselves. They often sponsored activities that combined work, food and entertainment such as barn raisings, corn huskings, quilting bees, Grange meetings, church activities and school functions. Women organized shared meals and potluck events, as well as extended visits between families. The Grange was a nationwide farmers' organization, they reserved high offices for women, and gave them a voice in public affairs. | Was it men or women that primarily engaged in corn huskings? | {
"answer_start": [],
"text": []
} |
59d2a3ad2763a6001828414e | Great_Plains | Although the eastern image of farm life in the prairies emphasized the isolation of the lonely farmer and wife, plains residents created busy social lives for themselves. They often sponsored activities that combined work, food and entertainment such as barn raisings, corn huskings, quilting bees, Grange meetings, church activities and school functions. Women organized shared meals and potluck events, as well as extended visits between families. The Grange was a nationwide farmers' organization, they reserved high offices for women, and gave them a voice in public affairs. | Between men and women, who handled most school functions? | {
"answer_start": [],
"text": []
} |
570b8219ec8fbc190045ba46 | Great_Plains | From the 1950s on, many areas of the Great Plains have become productive crop-growing areas because of extensive irrigation on large landholdings. The United States is a major exporter of agricultural products. The southern portion of the Great Plains lies over the Ogallala Aquifer, a huge underground layer of water-bearing strata dating from the last ice age. Center pivot irrigation is used extensively in drier sections of the Great Plains, resulting in aquifer depletion at a rate that is greater than the ground's ability to recharge. | around when did the great plains become productive for crop growing | {
"answer_start": [
9
],
"text": [
"1950s"
]
} |
570b8219ec8fbc190045ba47 | Great_Plains | From the 1950s on, many areas of the Great Plains have become productive crop-growing areas because of extensive irrigation on large landholdings. The United States is a major exporter of agricultural products. The southern portion of the Great Plains lies over the Ogallala Aquifer, a huge underground layer of water-bearing strata dating from the last ice age. Center pivot irrigation is used extensively in drier sections of the Great Plains, resulting in aquifer depletion at a rate that is greater than the ground's ability to recharge. | what is the large underground layer of water in the great plains called? | {
"answer_start": [
266
],
"text": [
"Ogallala Aquifer"
]
} |
570b8219ec8fbc190045ba48 | Great_Plains | From the 1950s on, many areas of the Great Plains have become productive crop-growing areas because of extensive irrigation on large landholdings. The United States is a major exporter of agricultural products. The southern portion of the Great Plains lies over the Ogallala Aquifer, a huge underground layer of water-bearing strata dating from the last ice age. Center pivot irrigation is used extensively in drier sections of the Great Plains, resulting in aquifer depletion at a rate that is greater than the ground's ability to recharge. | what type of irrigation is used in the great plains? | {
"answer_start": [
363
],
"text": [
"Center pivot irrigation"
]
} |
59d2a4a12763a60018284153 | Great_Plains | From the 1950s on, many areas of the Great Plains have become productive crop-growing areas because of extensive irrigation on large landholdings. The United States is a major exporter of agricultural products. The southern portion of the Great Plains lies over the Ogallala Aquifer, a huge underground layer of water-bearing strata dating from the last ice age. Center pivot irrigation is used extensively in drier sections of the Great Plains, resulting in aquifer depletion at a rate that is greater than the ground's ability to recharge. | When was the last ice age? | {
"answer_start": [],
"text": []
} |
59d2a4a12763a60018284154 | Great_Plains | From the 1950s on, many areas of the Great Plains have become productive crop-growing areas because of extensive irrigation on large landholdings. The United States is a major exporter of agricultural products. The southern portion of the Great Plains lies over the Ogallala Aquifer, a huge underground layer of water-bearing strata dating from the last ice age. Center pivot irrigation is used extensively in drier sections of the Great Plains, resulting in aquifer depletion at a rate that is greater than the ground's ability to recharge. | In what decade did center pivot irrigation get invented? | {
"answer_start": [],
"text": []
} |
59d2a4a12763a60018284155 | Great_Plains | From the 1950s on, many areas of the Great Plains have become productive crop-growing areas because of extensive irrigation on large landholdings. The United States is a major exporter of agricultural products. The southern portion of the Great Plains lies over the Ogallala Aquifer, a huge underground layer of water-bearing strata dating from the last ice age. Center pivot irrigation is used extensively in drier sections of the Great Plains, resulting in aquifer depletion at a rate that is greater than the ground's ability to recharge. | In what decade did aquafier depletion begin to outpace the ground's ability to recharge? | {
"answer_start": [],
"text": []
} |
59d2a4a12763a60018284156 | Great_Plains | From the 1950s on, many areas of the Great Plains have become productive crop-growing areas because of extensive irrigation on large landholdings. The United States is a major exporter of agricultural products. The southern portion of the Great Plains lies over the Ogallala Aquifer, a huge underground layer of water-bearing strata dating from the last ice age. Center pivot irrigation is used extensively in drier sections of the Great Plains, resulting in aquifer depletion at a rate that is greater than the ground's ability to recharge. | In what country was center pivot irrigation invented? | {
"answer_start": [],
"text": []
} |
570b828bec8fbc190045ba4c | Great_Plains | The Great Plains is the broad expanse of flat land (a plain), much of it covered in prairie, steppe and grassland, that lies west of the Mississippi River tallgrass prairie states and east of the Rocky Mountains in the United States and Canada. This area covers parts, but not all, of the states of Colorado, Kansas, Montana, Nebraska, New Mexico, North Dakota, Oklahoma, South Dakota, Texas, and Wyoming, and the Canadian provinces of Alberta, Manitoba and Saskatchewan. The region is known for supporting extensive cattle ranching and dry farming. | what is the great plains? | {
"answer_start": [
24
],
"text": [
"broad expanse of flat land"
]
} |
570b828bec8fbc190045ba4d | Great_Plains | The Great Plains is the broad expanse of flat land (a plain), much of it covered in prairie, steppe and grassland, that lies west of the Mississippi River tallgrass prairie states and east of the Rocky Mountains in the United States and Canada. This area covers parts, but not all, of the states of Colorado, Kansas, Montana, Nebraska, New Mexico, North Dakota, Oklahoma, South Dakota, Texas, and Wyoming, and the Canadian provinces of Alberta, Manitoba and Saskatchewan. The region is known for supporting extensive cattle ranching and dry farming. | where does the great plains lie? | {
"answer_start": [
125
],
"text": [
"west of the Mississippi River"
]
} |
570b828bec8fbc190045ba4e | Great_Plains | The Great Plains is the broad expanse of flat land (a plain), much of it covered in prairie, steppe and grassland, that lies west of the Mississippi River tallgrass prairie states and east of the Rocky Mountains in the United States and Canada. This area covers parts, but not all, of the states of Colorado, Kansas, Montana, Nebraska, New Mexico, North Dakota, Oklahoma, South Dakota, Texas, and Wyoming, and the Canadian provinces of Alberta, Manitoba and Saskatchewan. The region is known for supporting extensive cattle ranching and dry farming. | what is the region known for? | {
"answer_start": [
507
],
"text": [
"extensive cattle ranching"
]
} |
59d297d52763a600182840eb | Great_Plains | The Great Plains is the broad expanse of flat land (a plain), much of it covered in prairie, steppe and grassland, that lies west of the Mississippi River tallgrass prairie states and east of the Rocky Mountains in the United States and Canada. This area covers parts, but not all, of the states of Colorado, Kansas, Montana, Nebraska, New Mexico, North Dakota, Oklahoma, South Dakota, Texas, and Wyoming, and the Canadian provinces of Alberta, Manitoba and Saskatchewan. The region is known for supporting extensive cattle ranching and dry farming. | What lies east of the Mississippi River tallgrass prairie states? | {
"answer_start": [],
"text": []
} |
59d297d52763a600182840ec | Great_Plains | The Great Plains is the broad expanse of flat land (a plain), much of it covered in prairie, steppe and grassland, that lies west of the Mississippi River tallgrass prairie states and east of the Rocky Mountains in the United States and Canada. This area covers parts, but not all, of the states of Colorado, Kansas, Montana, Nebraska, New Mexico, North Dakota, Oklahoma, South Dakota, Texas, and Wyoming, and the Canadian provinces of Alberta, Manitoba and Saskatchewan. The region is known for supporting extensive cattle ranching and dry farming. | What lies west of the Rocky Mountains? | {
"answer_start": [],
"text": []
} |
59d297d52763a600182840ed | Great_Plains | The Great Plains is the broad expanse of flat land (a plain), much of it covered in prairie, steppe and grassland, that lies west of the Mississippi River tallgrass prairie states and east of the Rocky Mountains in the United States and Canada. This area covers parts, but not all, of the states of Colorado, Kansas, Montana, Nebraska, New Mexico, North Dakota, Oklahoma, South Dakota, Texas, and Wyoming, and the Canadian provinces of Alberta, Manitoba and Saskatchewan. The region is known for supporting extensive cattle ranching and dry farming. | What lies north of the Great Plains? | {
"answer_start": [],
"text": []
} |
59d297d52763a600182840ee | Great_Plains | The Great Plains is the broad expanse of flat land (a plain), much of it covered in prairie, steppe and grassland, that lies west of the Mississippi River tallgrass prairie states and east of the Rocky Mountains in the United States and Canada. This area covers parts, but not all, of the states of Colorado, Kansas, Montana, Nebraska, New Mexico, North Dakota, Oklahoma, South Dakota, Texas, and Wyoming, and the Canadian provinces of Alberta, Manitoba and Saskatchewan. The region is known for supporting extensive cattle ranching and dry farming. | What lies south of the Great Plains? | {
"answer_start": [],
"text": []
} |
59d297d52763a600182840ef | Great_Plains | The Great Plains is the broad expanse of flat land (a plain), much of it covered in prairie, steppe and grassland, that lies west of the Mississippi River tallgrass prairie states and east of the Rocky Mountains in the United States and Canada. This area covers parts, but not all, of the states of Colorado, Kansas, Montana, Nebraska, New Mexico, North Dakota, Oklahoma, South Dakota, Texas, and Wyoming, and the Canadian provinces of Alberta, Manitoba and Saskatchewan. The region is known for supporting extensive cattle ranching and dry farming. | Name one of the states the Mississippi River flows through. | {
"answer_start": [],
"text": []
} |
570b83a86b8089140040f97e | Great_Plains | The North American Environmental Atlas, produced by the Commission for Environmental Cooperation, a NAFTA agency composed of the geographical agencies of the Mexican, American, and Canadian governments uses the "Great Plains" as an ecoregion synonymous with predominant prairies and grasslands rather than as physiographic region defined by topography. The Great Plains ecoregion includes five sub-regions: Temperate Prairies, West-Central Semi-Arid Prairies, South-Central Semi-Arid Prairies, Texas Louisiana Coastal Plains, and Tamaulipus-Texas Semi-Arid Plain, which overlap or expand upon other Great Plains designations. | who is the North American Environmental Atlas made by? | {
"answer_start": [
56
],
"text": [
"Commission for Environmental Cooperation"
]
} |
570b83a86b8089140040f97f | Great_Plains | The North American Environmental Atlas, produced by the Commission for Environmental Cooperation, a NAFTA agency composed of the geographical agencies of the Mexican, American, and Canadian governments uses the "Great Plains" as an ecoregion synonymous with predominant prairies and grasslands rather than as physiographic region defined by topography. The Great Plains ecoregion includes five sub-regions: Temperate Prairies, West-Central Semi-Arid Prairies, South-Central Semi-Arid Prairies, Texas Louisiana Coastal Plains, and Tamaulipus-Texas Semi-Arid Plain, which overlap or expand upon other Great Plains designations. | what countries is the Commission for Environmental Cooperation made up of? | {
"answer_start": [
158
],
"text": [
"Mexican, American, and Canadian governments"
]
} |
59d2996f2763a600182840f5 | Great_Plains | The North American Environmental Atlas, produced by the Commission for Environmental Cooperation, a NAFTA agency composed of the geographical agencies of the Mexican, American, and Canadian governments uses the "Great Plains" as an ecoregion synonymous with predominant prairies and grasslands rather than as physiographic region defined by topography. The Great Plains ecoregion includes five sub-regions: Temperate Prairies, West-Central Semi-Arid Prairies, South-Central Semi-Arid Prairies, Texas Louisiana Coastal Plains, and Tamaulipus-Texas Semi-Arid Plain, which overlap or expand upon other Great Plains designations. | What states comprise the Temperate Prairies of the Great Plains? | {
"answer_start": [],
"text": []
} |
59d2996f2763a600182840f6 | Great_Plains | The North American Environmental Atlas, produced by the Commission for Environmental Cooperation, a NAFTA agency composed of the geographical agencies of the Mexican, American, and Canadian governments uses the "Great Plains" as an ecoregion synonymous with predominant prairies and grasslands rather than as physiographic region defined by topography. The Great Plains ecoregion includes five sub-regions: Temperate Prairies, West-Central Semi-Arid Prairies, South-Central Semi-Arid Prairies, Texas Louisiana Coastal Plains, and Tamaulipus-Texas Semi-Arid Plain, which overlap or expand upon other Great Plains designations. | What states are in the West-Central Semi-Arid Praries? | {
"answer_start": [],
"text": []
} |
59d2996f2763a600182840f7 | Great_Plains | The North American Environmental Atlas, produced by the Commission for Environmental Cooperation, a NAFTA agency composed of the geographical agencies of the Mexican, American, and Canadian governments uses the "Great Plains" as an ecoregion synonymous with predominant prairies and grasslands rather than as physiographic region defined by topography. The Great Plains ecoregion includes five sub-regions: Temperate Prairies, West-Central Semi-Arid Prairies, South-Central Semi-Arid Prairies, Texas Louisiana Coastal Plains, and Tamaulipus-Texas Semi-Arid Plain, which overlap or expand upon other Great Plains designations. | Which states are in the South-Central Semi-Arid Prairies? | {
"answer_start": [],
"text": []
} |
59d2996f2763a600182840f8 | Great_Plains | The North American Environmental Atlas, produced by the Commission for Environmental Cooperation, a NAFTA agency composed of the geographical agencies of the Mexican, American, and Canadian governments uses the "Great Plains" as an ecoregion synonymous with predominant prairies and grasslands rather than as physiographic region defined by topography. The Great Plains ecoregion includes five sub-regions: Temperate Prairies, West-Central Semi-Arid Prairies, South-Central Semi-Arid Prairies, Texas Louisiana Coastal Plains, and Tamaulipus-Texas Semi-Arid Plain, which overlap or expand upon other Great Plains designations. | Between the Canadian, American, and Mexican portions of the Great Plains in which area does most of it lie? | {
"answer_start": [],
"text": []
} |
570b8534ec8fbc190045ba52 | Great_Plains | The railroads opened up the Great Plains for settlement, for now it was possible to ship wheat and other crops at low cost to the urban markets in the East, and Europe. Homestead land was free for American settlers. Railroads sold their land at cheap rates to immigrants in expectation they would generate traffic as soon as farms were established. Immigrants poured in, especially from Germany and Scandinavia. On the plains, very few single men attempted to operate a farm or ranch by themselves; they clearly understood the need for a hard-working wife, and numerous children, to handle the many chores, including child-rearing, feeding and clothing the family, managing the housework, feeding the hired hands, and, especially after the 1930s, handling paperwork and financial details. During the early years of settlement, farm women played an integral role in assuring family survival by working outdoors. After approximately one generation, women increasingly left the fields, thus redefining their roles within the family. New technology including sewing and washing machines encouraged women to turn to domestic roles. The scientific housekeeping movement, promoted across the land by the media and government extension agents, as well as county fairs which featured achievements in home cookery and canning, advice columns for women regarding farm bookkeeping, and home economics courses in the schools. | what mainly opened the great plains for settlement? | {
"answer_start": [
4
],
"text": [
"railroads"
]
} |
570b8534ec8fbc190045ba53 | Great_Plains | The railroads opened up the Great Plains for settlement, for now it was possible to ship wheat and other crops at low cost to the urban markets in the East, and Europe. Homestead land was free for American settlers. Railroads sold their land at cheap rates to immigrants in expectation they would generate traffic as soon as farms were established. Immigrants poured in, especially from Germany and Scandinavia. On the plains, very few single men attempted to operate a farm or ranch by themselves; they clearly understood the need for a hard-working wife, and numerous children, to handle the many chores, including child-rearing, feeding and clothing the family, managing the housework, feeding the hired hands, and, especially after the 1930s, handling paperwork and financial details. During the early years of settlement, farm women played an integral role in assuring family survival by working outdoors. After approximately one generation, women increasingly left the fields, thus redefining their roles within the family. New technology including sewing and washing machines encouraged women to turn to domestic roles. The scientific housekeeping movement, promoted across the land by the media and government extension agents, as well as county fairs which featured achievements in home cookery and canning, advice columns for women regarding farm bookkeeping, and home economics courses in the schools. | what did the railroads make it easy to do? | {
"answer_start": [
84
],
"text": [
"ship wheat and other crops"
]
} |
570b8534ec8fbc190045ba54 | Great_Plains | The railroads opened up the Great Plains for settlement, for now it was possible to ship wheat and other crops at low cost to the urban markets in the East, and Europe. Homestead land was free for American settlers. Railroads sold their land at cheap rates to immigrants in expectation they would generate traffic as soon as farms were established. Immigrants poured in, especially from Germany and Scandinavia. On the plains, very few single men attempted to operate a farm or ranch by themselves; they clearly understood the need for a hard-working wife, and numerous children, to handle the many chores, including child-rearing, feeding and clothing the family, managing the housework, feeding the hired hands, and, especially after the 1930s, handling paperwork and financial details. During the early years of settlement, farm women played an integral role in assuring family survival by working outdoors. After approximately one generation, women increasingly left the fields, thus redefining their roles within the family. New technology including sewing and washing machines encouraged women to turn to domestic roles. The scientific housekeeping movement, promoted across the land by the media and government extension agents, as well as county fairs which featured achievements in home cookery and canning, advice columns for women regarding farm bookkeeping, and home economics courses in the schools. | who did the railroads sell cheap lands to? | {
"answer_start": [
260
],
"text": [
"immigrants"
]
} |
570b8534ec8fbc190045ba55 | Great_Plains | The railroads opened up the Great Plains for settlement, for now it was possible to ship wheat and other crops at low cost to the urban markets in the East, and Europe. Homestead land was free for American settlers. Railroads sold their land at cheap rates to immigrants in expectation they would generate traffic as soon as farms were established. Immigrants poured in, especially from Germany and Scandinavia. On the plains, very few single men attempted to operate a farm or ranch by themselves; they clearly understood the need for a hard-working wife, and numerous children, to handle the many chores, including child-rearing, feeding and clothing the family, managing the housework, feeding the hired hands, and, especially after the 1930s, handling paperwork and financial details. During the early years of settlement, farm women played an integral role in assuring family survival by working outdoors. After approximately one generation, women increasingly left the fields, thus redefining their roles within the family. New technology including sewing and washing machines encouraged women to turn to domestic roles. The scientific housekeeping movement, promoted across the land by the media and government extension agents, as well as county fairs which featured achievements in home cookery and canning, advice columns for women regarding farm bookkeeping, and home economics courses in the schools. | who two new technologies were introducted in the 1930s? | {
"answer_start": [
1055
],
"text": [
"sewing and washing machines"
]
} |
59d2a2d72763a60018284141 | Great_Plains | The railroads opened up the Great Plains for settlement, for now it was possible to ship wheat and other crops at low cost to the urban markets in the East, and Europe. Homestead land was free for American settlers. Railroads sold their land at cheap rates to immigrants in expectation they would generate traffic as soon as farms were established. Immigrants poured in, especially from Germany and Scandinavia. On the plains, very few single men attempted to operate a farm or ranch by themselves; they clearly understood the need for a hard-working wife, and numerous children, to handle the many chores, including child-rearing, feeding and clothing the family, managing the housework, feeding the hired hands, and, especially after the 1930s, handling paperwork and financial details. During the early years of settlement, farm women played an integral role in assuring family survival by working outdoors. After approximately one generation, women increasingly left the fields, thus redefining their roles within the family. New technology including sewing and washing machines encouraged women to turn to domestic roles. The scientific housekeeping movement, promoted across the land by the media and government extension agents, as well as county fairs which featured achievements in home cookery and canning, advice columns for women regarding farm bookkeeping, and home economics courses in the schools. | In what decade did railroads start to appear in the Great Plains? | {
"answer_start": [],
"text": []
} |
59d2a2d72763a60018284142 | Great_Plains | The railroads opened up the Great Plains for settlement, for now it was possible to ship wheat and other crops at low cost to the urban markets in the East, and Europe. Homestead land was free for American settlers. Railroads sold their land at cheap rates to immigrants in expectation they would generate traffic as soon as farms were established. Immigrants poured in, especially from Germany and Scandinavia. On the plains, very few single men attempted to operate a farm or ranch by themselves; they clearly understood the need for a hard-working wife, and numerous children, to handle the many chores, including child-rearing, feeding and clothing the family, managing the housework, feeding the hired hands, and, especially after the 1930s, handling paperwork and financial details. During the early years of settlement, farm women played an integral role in assuring family survival by working outdoors. After approximately one generation, women increasingly left the fields, thus redefining their roles within the family. New technology including sewing and washing machines encouraged women to turn to domestic roles. The scientific housekeeping movement, promoted across the land by the media and government extension agents, as well as county fairs which featured achievements in home cookery and canning, advice columns for women regarding farm bookkeeping, and home economics courses in the schools. | In what decade did many women work outdoors on the Great Plains? | {
"answer_start": [],
"text": []
} |
59d2a2d72763a60018284143 | Great_Plains | The railroads opened up the Great Plains for settlement, for now it was possible to ship wheat and other crops at low cost to the urban markets in the East, and Europe. Homestead land was free for American settlers. Railroads sold their land at cheap rates to immigrants in expectation they would generate traffic as soon as farms were established. Immigrants poured in, especially from Germany and Scandinavia. On the plains, very few single men attempted to operate a farm or ranch by themselves; they clearly understood the need for a hard-working wife, and numerous children, to handle the many chores, including child-rearing, feeding and clothing the family, managing the housework, feeding the hired hands, and, especially after the 1930s, handling paperwork and financial details. During the early years of settlement, farm women played an integral role in assuring family survival by working outdoors. After approximately one generation, women increasingly left the fields, thus redefining their roles within the family. New technology including sewing and washing machines encouraged women to turn to domestic roles. The scientific housekeeping movement, promoted across the land by the media and government extension agents, as well as county fairs which featured achievements in home cookery and canning, advice columns for women regarding farm bookkeeping, and home economics courses in the schools. | In what decade were washing machines introduced? | {
"answer_start": [],
"text": []
} |
59d2a2d72763a60018284144 | Great_Plains | The railroads opened up the Great Plains for settlement, for now it was possible to ship wheat and other crops at low cost to the urban markets in the East, and Europe. Homestead land was free for American settlers. Railroads sold their land at cheap rates to immigrants in expectation they would generate traffic as soon as farms were established. Immigrants poured in, especially from Germany and Scandinavia. On the plains, very few single men attempted to operate a farm or ranch by themselves; they clearly understood the need for a hard-working wife, and numerous children, to handle the many chores, including child-rearing, feeding and clothing the family, managing the housework, feeding the hired hands, and, especially after the 1930s, handling paperwork and financial details. During the early years of settlement, farm women played an integral role in assuring family survival by working outdoors. After approximately one generation, women increasingly left the fields, thus redefining their roles within the family. New technology including sewing and washing machines encouraged women to turn to domestic roles. The scientific housekeeping movement, promoted across the land by the media and government extension agents, as well as county fairs which featured achievements in home cookery and canning, advice columns for women regarding farm bookkeeping, and home economics courses in the schools. | In what decade did schools start offering home economics courses? | {
"answer_start": [],
"text": []
} |
59d2a2d72763a60018284145 | Great_Plains | The railroads opened up the Great Plains for settlement, for now it was possible to ship wheat and other crops at low cost to the urban markets in the East, and Europe. Homestead land was free for American settlers. Railroads sold their land at cheap rates to immigrants in expectation they would generate traffic as soon as farms were established. Immigrants poured in, especially from Germany and Scandinavia. On the plains, very few single men attempted to operate a farm or ranch by themselves; they clearly understood the need for a hard-working wife, and numerous children, to handle the many chores, including child-rearing, feeding and clothing the family, managing the housework, feeding the hired hands, and, especially after the 1930s, handling paperwork and financial details. During the early years of settlement, farm women played an integral role in assuring family survival by working outdoors. After approximately one generation, women increasingly left the fields, thus redefining their roles within the family. New technology including sewing and washing machines encouraged women to turn to domestic roles. The scientific housekeeping movement, promoted across the land by the media and government extension agents, as well as county fairs which featured achievements in home cookery and canning, advice columns for women regarding farm bookkeeping, and home economics courses in the schools. | In what decade did the Great Plains start shipping wheat east? | {
"answer_start": [],
"text": []
} |
570b85a5ec8fbc190045ba5a | Great_Plains | During the Cenozoic era, specifically about 25 million years ago during the Miocene and Pliocene epochs, the continental climate became favorable to the evolution of grasslands. Existing forest biomes declined and grasslands became much more widespread. The grasslands provided a new niche for mammals, including many ungulates and glires, that switched from browsing diets to grazing diets. Traditionally, the spread of grasslands and the development of grazers have been strongly linked. However, an examination of mammalian teeth suggests that it is the open, gritty habitat and not the grass itself which is linked to diet changes in mammals, giving rise to the "grit, not grass" hypothesis. | about how long ago did the climate become favorable? | {
"answer_start": [
38
],
"text": [
"about 25 million years ago"
]
} |
570b85a5ec8fbc190045ba5b | Great_Plains | During the Cenozoic era, specifically about 25 million years ago during the Miocene and Pliocene epochs, the continental climate became favorable to the evolution of grasslands. Existing forest biomes declined and grasslands became much more widespread. The grasslands provided a new niche for mammals, including many ungulates and glires, that switched from browsing diets to grazing diets. Traditionally, the spread of grasslands and the development of grazers have been strongly linked. However, an examination of mammalian teeth suggests that it is the open, gritty habitat and not the grass itself which is linked to diet changes in mammals, giving rise to the "grit, not grass" hypothesis. | what animals did the grasslands provide a new home for? | {
"answer_start": [
294
],
"text": [
"mammals"
]
} |
570b85a5ec8fbc190045ba5c | Great_Plains | During the Cenozoic era, specifically about 25 million years ago during the Miocene and Pliocene epochs, the continental climate became favorable to the evolution of grasslands. Existing forest biomes declined and grasslands became much more widespread. The grasslands provided a new niche for mammals, including many ungulates and glires, that switched from browsing diets to grazing diets. Traditionally, the spread of grasslands and the development of grazers have been strongly linked. However, an examination of mammalian teeth suggests that it is the open, gritty habitat and not the grass itself which is linked to diet changes in mammals, giving rise to the "grit, not grass" hypothesis. | what diet did the mammals switch to from browsing diets? | {
"answer_start": [
377
],
"text": [
"grazing diets"
]
} |
570b85a5ec8fbc190045ba5d | Great_Plains | During the Cenozoic era, specifically about 25 million years ago during the Miocene and Pliocene epochs, the continental climate became favorable to the evolution of grasslands. Existing forest biomes declined and grasslands became much more widespread. The grasslands provided a new niche for mammals, including many ungulates and glires, that switched from browsing diets to grazing diets. Traditionally, the spread of grasslands and the development of grazers have been strongly linked. However, an examination of mammalian teeth suggests that it is the open, gritty habitat and not the grass itself which is linked to diet changes in mammals, giving rise to the "grit, not grass" hypothesis. | the spread of grasslands and what have been strongly linked? | {
"answer_start": [
440
],
"text": [
"development of grazers"
]
} |
59d29c042763a60018284105 | Great_Plains | During the Cenozoic era, specifically about 25 million years ago during the Miocene and Pliocene epochs, the continental climate became favorable to the evolution of grasslands. Existing forest biomes declined and grasslands became much more widespread. The grasslands provided a new niche for mammals, including many ungulates and glires, that switched from browsing diets to grazing diets. Traditionally, the spread of grasslands and the development of grazers have been strongly linked. However, an examination of mammalian teeth suggests that it is the open, gritty habitat and not the grass itself which is linked to diet changes in mammals, giving rise to the "grit, not grass" hypothesis. | How many years ago did the Cenozoic era start? | {
"answer_start": [],
"text": []
} |
59d29c042763a60018284106 | Great_Plains | During the Cenozoic era, specifically about 25 million years ago during the Miocene and Pliocene epochs, the continental climate became favorable to the evolution of grasslands. Existing forest biomes declined and grasslands became much more widespread. The grasslands provided a new niche for mammals, including many ungulates and glires, that switched from browsing diets to grazing diets. Traditionally, the spread of grasslands and the development of grazers have been strongly linked. However, an examination of mammalian teeth suggests that it is the open, gritty habitat and not the grass itself which is linked to diet changes in mammals, giving rise to the "grit, not grass" hypothesis. | In what era did ungulates start eating a browsing diet? | {
"answer_start": [],
"text": []
} |
59d29c042763a60018284107 | Great_Plains | During the Cenozoic era, specifically about 25 million years ago during the Miocene and Pliocene epochs, the continental climate became favorable to the evolution of grasslands. Existing forest biomes declined and grasslands became much more widespread. The grasslands provided a new niche for mammals, including many ungulates and glires, that switched from browsing diets to grazing diets. Traditionally, the spread of grasslands and the development of grazers have been strongly linked. However, an examination of mammalian teeth suggests that it is the open, gritty habitat and not the grass itself which is linked to diet changes in mammals, giving rise to the "grit, not grass" hypothesis. | In what era did mammals develop teeth? | {
"answer_start": [],
"text": []
} |
59d29c042763a60018284108 | Great_Plains | During the Cenozoic era, specifically about 25 million years ago during the Miocene and Pliocene epochs, the continental climate became favorable to the evolution of grasslands. Existing forest biomes declined and grasslands became much more widespread. The grasslands provided a new niche for mammals, including many ungulates and glires, that switched from browsing diets to grazing diets. Traditionally, the spread of grasslands and the development of grazers have been strongly linked. However, an examination of mammalian teeth suggests that it is the open, gritty habitat and not the grass itself which is linked to diet changes in mammals, giving rise to the "grit, not grass" hypothesis. | In what era did forest biomes start to grow? | {
"answer_start": [],
"text": []
} |
59d29c042763a60018284109 | Great_Plains | During the Cenozoic era, specifically about 25 million years ago during the Miocene and Pliocene epochs, the continental climate became favorable to the evolution of grasslands. Existing forest biomes declined and grasslands became much more widespread. The grasslands provided a new niche for mammals, including many ungulates and glires, that switched from browsing diets to grazing diets. Traditionally, the spread of grasslands and the development of grazers have been strongly linked. However, an examination of mammalian teeth suggests that it is the open, gritty habitat and not the grass itself which is linked to diet changes in mammals, giving rise to the "grit, not grass" hypothesis. | When did the Cenozoic era end? | {
"answer_start": [],
"text": []
} |
570b8627ec8fbc190045ba62 | Great_Plains | To allow for agricultural development of the Great Plains and house a growing population, the US passed the Homestead Acts of 1862: it allowed a settler to claim up to 160 acres (65 ha) of land, provided that he lived on it for a period of five years and cultivated it. The provisions were expanded under the Kinkaid Act of 1904 to include a homestead of an entire section. Hundreds of thousands of people claimed such homesteads, sometimes building sod houses out of the very turf of their land. Many of them were not skilled dryland farmers and failures were frequent. Much of the Plains were settled during relatively wet years. Government experts did not understand how farmers should cultivate the prairies and gave advice counter to what would have worked[citation needed]. Germans from Russia who had previously farmed, under similar circumstances, in what is now Ukraine were marginally more successful than other homesteaders. The Dominion Lands Act of 1871 served a similar function for establishing homesteads on the prairies in Canada. | when did the US pass the Homestead ACt? | {
"answer_start": [
126
],
"text": [
"1862"
]
} |
570b8627ec8fbc190045ba63 | Great_Plains | To allow for agricultural development of the Great Plains and house a growing population, the US passed the Homestead Acts of 1862: it allowed a settler to claim up to 160 acres (65 ha) of land, provided that he lived on it for a period of five years and cultivated it. The provisions were expanded under the Kinkaid Act of 1904 to include a homestead of an entire section. Hundreds of thousands of people claimed such homesteads, sometimes building sod houses out of the very turf of their land. Many of them were not skilled dryland farmers and failures were frequent. Much of the Plains were settled during relatively wet years. Government experts did not understand how farmers should cultivate the prairies and gave advice counter to what would have worked[citation needed]. Germans from Russia who had previously farmed, under similar circumstances, in what is now Ukraine were marginally more successful than other homesteaders. The Dominion Lands Act of 1871 served a similar function for establishing homesteads on the prairies in Canada. | how much land did the Homestead Act allow a person to claim? | {
"answer_start": [
162
],
"text": [
"up to 160 acres"
]
} |
570b8627ec8fbc190045ba64 | Great_Plains | To allow for agricultural development of the Great Plains and house a growing population, the US passed the Homestead Acts of 1862: it allowed a settler to claim up to 160 acres (65 ha) of land, provided that he lived on it for a period of five years and cultivated it. The provisions were expanded under the Kinkaid Act of 1904 to include a homestead of an entire section. Hundreds of thousands of people claimed such homesteads, sometimes building sod houses out of the very turf of their land. Many of them were not skilled dryland farmers and failures were frequent. Much of the Plains were settled during relatively wet years. Government experts did not understand how farmers should cultivate the prairies and gave advice counter to what would have worked[citation needed]. Germans from Russia who had previously farmed, under similar circumstances, in what is now Ukraine were marginally more successful than other homesteaders. The Dominion Lands Act of 1871 served a similar function for establishing homesteads on the prairies in Canada. | how long did the person have to live on the land? | {
"answer_start": [
240
],
"text": [
"five years"
]
} |
570b8627ec8fbc190045ba65 | Great_Plains | To allow for agricultural development of the Great Plains and house a growing population, the US passed the Homestead Acts of 1862: it allowed a settler to claim up to 160 acres (65 ha) of land, provided that he lived on it for a period of five years and cultivated it. The provisions were expanded under the Kinkaid Act of 1904 to include a homestead of an entire section. Hundreds of thousands of people claimed such homesteads, sometimes building sod houses out of the very turf of their land. Many of them were not skilled dryland farmers and failures were frequent. Much of the Plains were settled during relatively wet years. Government experts did not understand how farmers should cultivate the prairies and gave advice counter to what would have worked[citation needed]. Germans from Russia who had previously farmed, under similar circumstances, in what is now Ukraine were marginally more successful than other homesteaders. The Dominion Lands Act of 1871 served a similar function for establishing homesteads on the prairies in Canada. | when was the Kinkaid Act brought about? | {
"answer_start": [
324
],
"text": [
"1904"
]
} |
570b8627ec8fbc190045ba66 | Great_Plains | To allow for agricultural development of the Great Plains and house a growing population, the US passed the Homestead Acts of 1862: it allowed a settler to claim up to 160 acres (65 ha) of land, provided that he lived on it for a period of five years and cultivated it. The provisions were expanded under the Kinkaid Act of 1904 to include a homestead of an entire section. Hundreds of thousands of people claimed such homesteads, sometimes building sod houses out of the very turf of their land. Many of them were not skilled dryland farmers and failures were frequent. Much of the Plains were settled during relatively wet years. Government experts did not understand how farmers should cultivate the prairies and gave advice counter to what would have worked[citation needed]. Germans from Russia who had previously farmed, under similar circumstances, in what is now Ukraine were marginally more successful than other homesteaders. The Dominion Lands Act of 1871 served a similar function for establishing homesteads on the prairies in Canada. | the dominion act was passed in what year | {
"answer_start": [
962
],
"text": [
"1871"
]
} |
59d2a1c92763a60018284137 | Great_Plains | To allow for agricultural development of the Great Plains and house a growing population, the US passed the Homestead Acts of 1862: it allowed a settler to claim up to 160 acres (65 ha) of land, provided that he lived on it for a period of five years and cultivated it. The provisions were expanded under the Kinkaid Act of 1904 to include a homestead of an entire section. Hundreds of thousands of people claimed such homesteads, sometimes building sod houses out of the very turf of their land. Many of them were not skilled dryland farmers and failures were frequent. Much of the Plains were settled during relatively wet years. Government experts did not understand how farmers should cultivate the prairies and gave advice counter to what would have worked[citation needed]. Germans from Russia who had previously farmed, under similar circumstances, in what is now Ukraine were marginally more successful than other homesteaders. The Dominion Lands Act of 1871 served a similar function for establishing homesteads on the prairies in Canada. | In what year was the Kinkaid Act repealed? | {
"answer_start": [],
"text": []
} |
59d2a1c92763a60018284138 | Great_Plains | To allow for agricultural development of the Great Plains and house a growing population, the US passed the Homestead Acts of 1862: it allowed a settler to claim up to 160 acres (65 ha) of land, provided that he lived on it for a period of five years and cultivated it. The provisions were expanded under the Kinkaid Act of 1904 to include a homestead of an entire section. Hundreds of thousands of people claimed such homesteads, sometimes building sod houses out of the very turf of their land. Many of them were not skilled dryland farmers and failures were frequent. Much of the Plains were settled during relatively wet years. Government experts did not understand how farmers should cultivate the prairies and gave advice counter to what would have worked[citation needed]. Germans from Russia who had previously farmed, under similar circumstances, in what is now Ukraine were marginally more successful than other homesteaders. The Dominion Lands Act of 1871 served a similar function for establishing homesteads on the prairies in Canada. | In what year was the Dominions Lands Act repealed? | {
"answer_start": [],
"text": []
} |
59d2a1c92763a60018284139 | Great_Plains | To allow for agricultural development of the Great Plains and house a growing population, the US passed the Homestead Acts of 1862: it allowed a settler to claim up to 160 acres (65 ha) of land, provided that he lived on it for a period of five years and cultivated it. The provisions were expanded under the Kinkaid Act of 1904 to include a homestead of an entire section. Hundreds of thousands of people claimed such homesteads, sometimes building sod houses out of the very turf of their land. Many of them were not skilled dryland farmers and failures were frequent. Much of the Plains were settled during relatively wet years. Government experts did not understand how farmers should cultivate the prairies and gave advice counter to what would have worked[citation needed]. Germans from Russia who had previously farmed, under similar circumstances, in what is now Ukraine were marginally more successful than other homesteaders. The Dominion Lands Act of 1871 served a similar function for establishing homesteads on the prairies in Canada. | In what year did the relatively wet years of the Great Plains end? | {
"answer_start": [],
"text": []
} |
59d2a1c92763a6001828413a | Great_Plains | To allow for agricultural development of the Great Plains and house a growing population, the US passed the Homestead Acts of 1862: it allowed a settler to claim up to 160 acres (65 ha) of land, provided that he lived on it for a period of five years and cultivated it. The provisions were expanded under the Kinkaid Act of 1904 to include a homestead of an entire section. Hundreds of thousands of people claimed such homesteads, sometimes building sod houses out of the very turf of their land. Many of them were not skilled dryland farmers and failures were frequent. Much of the Plains were settled during relatively wet years. Government experts did not understand how farmers should cultivate the prairies and gave advice counter to what would have worked[citation needed]. Germans from Russia who had previously farmed, under similar circumstances, in what is now Ukraine were marginally more successful than other homesteaders. The Dominion Lands Act of 1871 served a similar function for establishing homesteads on the prairies in Canada. | What number of people established homestead in Canada? | {
"answer_start": [],
"text": []
} |
59d2a1c92763a6001828413b | Great_Plains | To allow for agricultural development of the Great Plains and house a growing population, the US passed the Homestead Acts of 1862: it allowed a settler to claim up to 160 acres (65 ha) of land, provided that he lived on it for a period of five years and cultivated it. The provisions were expanded under the Kinkaid Act of 1904 to include a homestead of an entire section. Hundreds of thousands of people claimed such homesteads, sometimes building sod houses out of the very turf of their land. Many of them were not skilled dryland farmers and failures were frequent. Much of the Plains were settled during relatively wet years. Government experts did not understand how farmers should cultivate the prairies and gave advice counter to what would have worked[citation needed]. Germans from Russia who had previously farmed, under similar circumstances, in what is now Ukraine were marginally more successful than other homesteaders. The Dominion Lands Act of 1871 served a similar function for establishing homesteads on the prairies in Canada. | How many homesteaders failed to establish cultivated land? | {
"answer_start": [],
"text": []
} |
570b8ef3ec8fbc190045ba6c | Infrared | Infrared radiation is used in industrial, scientific, and medical applications. Night-vision devices using active near-infrared illumination allow people or animals to be observed without the observer being detected. Infrared astronomy uses sensor-equipped telescopes to penetrate dusty regions of space, such as molecular clouds; detect objects such as planets, and to view highly red-shifted objects from the early days of the universe. Infrared thermal-imaging cameras are used to detect heat loss in insulated systems, to observe changing blood flow in the skin, and to detect overheating of electrical apparatus. | Along with industrial and medical, in what applications is infrared radiation used? | {
"answer_start": [
42
],
"text": [
"scientific"
]
} |
570b8ef3ec8fbc190045ba6d | Infrared | Infrared radiation is used in industrial, scientific, and medical applications. Night-vision devices using active near-infrared illumination allow people or animals to be observed without the observer being detected. Infrared astronomy uses sensor-equipped telescopes to penetrate dusty regions of space, such as molecular clouds; detect objects such as planets, and to view highly red-shifted objects from the early days of the universe. Infrared thermal-imaging cameras are used to detect heat loss in insulated systems, to observe changing blood flow in the skin, and to detect overheating of electrical apparatus. | What technology is used by night-vision devices? | {
"answer_start": [
107
],
"text": [
"active near-infrared illumination"
]
} |
570b8ef3ec8fbc190045ba6e | Infrared | Infrared radiation is used in industrial, scientific, and medical applications. Night-vision devices using active near-infrared illumination allow people or animals to be observed without the observer being detected. Infrared astronomy uses sensor-equipped telescopes to penetrate dusty regions of space, such as molecular clouds; detect objects such as planets, and to view highly red-shifted objects from the early days of the universe. Infrared thermal-imaging cameras are used to detect heat loss in insulated systems, to observe changing blood flow in the skin, and to detect overheating of electrical apparatus. | What discipline uses infrared telescopes to see through molecular clouds? | {
"answer_start": [
217
],
"text": [
"Infrared astronomy"
]
} |
570b8ef3ec8fbc190045ba6f | Infrared | Infrared radiation is used in industrial, scientific, and medical applications. Night-vision devices using active near-infrared illumination allow people or animals to be observed without the observer being detected. Infrared astronomy uses sensor-equipped telescopes to penetrate dusty regions of space, such as molecular clouds; detect objects such as planets, and to view highly red-shifted objects from the early days of the universe. Infrared thermal-imaging cameras are used to detect heat loss in insulated systems, to observe changing blood flow in the skin, and to detect overheating of electrical apparatus. | What color shift indicates that space objects date from the early days of the universe? | {
"answer_start": [
382
],
"text": [
"red"
]
} |
570b8ef3ec8fbc190045ba70 | Infrared | Infrared radiation is used in industrial, scientific, and medical applications. Night-vision devices using active near-infrared illumination allow people or animals to be observed without the observer being detected. Infrared astronomy uses sensor-equipped telescopes to penetrate dusty regions of space, such as molecular clouds; detect objects such as planets, and to view highly red-shifted objects from the early days of the universe. Infrared thermal-imaging cameras are used to detect heat loss in insulated systems, to observe changing blood flow in the skin, and to detect overheating of electrical apparatus. | What devices are used to observe insulated system heat loss? | {
"answer_start": [
439
],
"text": [
"Infrared thermal-imaging cameras"
]
} |
5a07bed60ff9ab00181693ac | Infrared | Infrared radiation is used in industrial, scientific, and medical applications. Night-vision devices using active near-infrared illumination allow people or animals to be observed without the observer being detected. Infrared astronomy uses sensor-equipped telescopes to penetrate dusty regions of space, such as molecular clouds; detect objects such as planets, and to view highly red-shifted objects from the early days of the universe. Infrared thermal-imaging cameras are used to detect heat loss in insulated systems, to observe changing blood flow in the skin, and to detect overheating of electrical apparatus. | What technology allows infrared thermal imaging cameras to observe people or animals without being detected? | {
"answer_start": [],
"text": []
} |
5a07bed60ff9ab00181693ad | Infrared | Infrared radiation is used in industrial, scientific, and medical applications. Night-vision devices using active near-infrared illumination allow people or animals to be observed without the observer being detected. Infrared astronomy uses sensor-equipped telescopes to penetrate dusty regions of space, such as molecular clouds; detect objects such as planets, and to view highly red-shifted objects from the early days of the universe. Infrared thermal-imaging cameras are used to detect heat loss in insulated systems, to observe changing blood flow in the skin, and to detect overheating of electrical apparatus. | What technology is used by night vision devices to observe changing blood flow in the skin? | {
"answer_start": [],
"text": []
} |
5a07bed60ff9ab00181693ae | Infrared | Infrared radiation is used in industrial, scientific, and medical applications. Night-vision devices using active near-infrared illumination allow people or animals to be observed without the observer being detected. Infrared astronomy uses sensor-equipped telescopes to penetrate dusty regions of space, such as molecular clouds; detect objects such as planets, and to view highly red-shifted objects from the early days of the universe. Infrared thermal-imaging cameras are used to detect heat loss in insulated systems, to observe changing blood flow in the skin, and to detect overheating of electrical apparatus. | What science discipline uses infrared thermal-imaging cameras to penetrate dusty regions of space? | {
"answer_start": [],
"text": []
} |
5a07bed60ff9ab00181693af | Infrared | Infrared radiation is used in industrial, scientific, and medical applications. Night-vision devices using active near-infrared illumination allow people or animals to be observed without the observer being detected. Infrared astronomy uses sensor-equipped telescopes to penetrate dusty regions of space, such as molecular clouds; detect objects such as planets, and to view highly red-shifted objects from the early days of the universe. Infrared thermal-imaging cameras are used to detect heat loss in insulated systems, to observe changing blood flow in the skin, and to detect overheating of electrical apparatus. | Along with industrial and medical, in what applications is infrared astronomy used? | {
"answer_start": [],
"text": []
} |
5a07bed60ff9ab00181693b0 | Infrared | Infrared radiation is used in industrial, scientific, and medical applications. Night-vision devices using active near-infrared illumination allow people or animals to be observed without the observer being detected. Infrared astronomy uses sensor-equipped telescopes to penetrate dusty regions of space, such as molecular clouds; detect objects such as planets, and to view highly red-shifted objects from the early days of the universe. Infrared thermal-imaging cameras are used to detect heat loss in insulated systems, to observe changing blood flow in the skin, and to detect overheating of electrical apparatus. | What type of radiation is used to detect heat loss in insulated systems? | {
"answer_start": [],
"text": []
} |
570b8f6cec8fbc190045ba76 | Infrared | The onset of infrared is defined (according to different standards) at various values typically between 700 nm and 800 nm, but the boundary between visible and infrared light is not precisely defined. The human eye is markedly less sensitive to light above 700 nm wavelength, so longer wavelengths make insignificant contributions to scenes illuminated by common light sources. However, particularly intense near-IR light (e.g., from IR lasers, IR LED sources, or from bright daylight with the visible light removed by colored gels) can be detected up to approximately 780 nm, and will be perceived as red light. Sources providing wavelengths as long as 1050 nm can be seen as a dull red glow in intense sources, causing some difficulty in near-IR illumination of scenes in the dark (usually this practical problem is solved by indirect illumination). Leaves are particularly bright in the near IR, and if all visible light leaks from around an IR-filter are blocked, and the eye is given a moment to adjust to the extremely dim image coming through a visually opaque IR-passing photographic filter, it is possible to see the Wood effect that consists of IR-glowing foliage. | At what wavelength does the human eye become significantly less sensitive to light? | {
"answer_start": [
257
],
"text": [
"700 nm"
]
} |
570b8f6cec8fbc190045ba77 | Infrared | The onset of infrared is defined (according to different standards) at various values typically between 700 nm and 800 nm, but the boundary between visible and infrared light is not precisely defined. The human eye is markedly less sensitive to light above 700 nm wavelength, so longer wavelengths make insignificant contributions to scenes illuminated by common light sources. However, particularly intense near-IR light (e.g., from IR lasers, IR LED sources, or from bright daylight with the visible light removed by colored gels) can be detected up to approximately 780 nm, and will be perceived as red light. Sources providing wavelengths as long as 1050 nm can be seen as a dull red glow in intense sources, causing some difficulty in near-IR illumination of scenes in the dark (usually this practical problem is solved by indirect illumination). Leaves are particularly bright in the near IR, and if all visible light leaks from around an IR-filter are blocked, and the eye is given a moment to adjust to the extremely dim image coming through a visually opaque IR-passing photographic filter, it is possible to see the Wood effect that consists of IR-glowing foliage. | What sort of light is generated by IR lasers? | {
"answer_start": [
408
],
"text": [
"near-IR"
]
} |
570b8f6cec8fbc190045ba78 | Infrared | The onset of infrared is defined (according to different standards) at various values typically between 700 nm and 800 nm, but the boundary between visible and infrared light is not precisely defined. The human eye is markedly less sensitive to light above 700 nm wavelength, so longer wavelengths make insignificant contributions to scenes illuminated by common light sources. However, particularly intense near-IR light (e.g., from IR lasers, IR LED sources, or from bright daylight with the visible light removed by colored gels) can be detected up to approximately 780 nm, and will be perceived as red light. Sources providing wavelengths as long as 1050 nm can be seen as a dull red glow in intense sources, causing some difficulty in near-IR illumination of scenes in the dark (usually this practical problem is solved by indirect illumination). Leaves are particularly bright in the near IR, and if all visible light leaks from around an IR-filter are blocked, and the eye is given a moment to adjust to the extremely dim image coming through a visually opaque IR-passing photographic filter, it is possible to see the Wood effect that consists of IR-glowing foliage. | Up to what wavelength does the human eye perceive IR LED sources as red? | {
"answer_start": [
569
],
"text": [
"780 nm"
]
} |
570b8f6cec8fbc190045ba79 | Infrared | The onset of infrared is defined (according to different standards) at various values typically between 700 nm and 800 nm, but the boundary between visible and infrared light is not precisely defined. The human eye is markedly less sensitive to light above 700 nm wavelength, so longer wavelengths make insignificant contributions to scenes illuminated by common light sources. However, particularly intense near-IR light (e.g., from IR lasers, IR LED sources, or from bright daylight with the visible light removed by colored gels) can be detected up to approximately 780 nm, and will be perceived as red light. Sources providing wavelengths as long as 1050 nm can be seen as a dull red glow in intense sources, causing some difficulty in near-IR illumination of scenes in the dark (usually this practical problem is solved by indirect illumination). Leaves are particularly bright in the near IR, and if all visible light leaks from around an IR-filter are blocked, and the eye is given a moment to adjust to the extremely dim image coming through a visually opaque IR-passing photographic filter, it is possible to see the Wood effect that consists of IR-glowing foliage. | Up to what wavelength does the human eye perceive certain intense lights as being dull red in color? | {
"answer_start": [
654
],
"text": [
"1050 nm"
]
} |
570b8f6cec8fbc190045ba7a | Infrared | The onset of infrared is defined (according to different standards) at various values typically between 700 nm and 800 nm, but the boundary between visible and infrared light is not precisely defined. The human eye is markedly less sensitive to light above 700 nm wavelength, so longer wavelengths make insignificant contributions to scenes illuminated by common light sources. However, particularly intense near-IR light (e.g., from IR lasers, IR LED sources, or from bright daylight with the visible light removed by colored gels) can be detected up to approximately 780 nm, and will be perceived as red light. Sources providing wavelengths as long as 1050 nm can be seen as a dull red glow in intense sources, causing some difficulty in near-IR illumination of scenes in the dark (usually this practical problem is solved by indirect illumination). Leaves are particularly bright in the near IR, and if all visible light leaks from around an IR-filter are blocked, and the eye is given a moment to adjust to the extremely dim image coming through a visually opaque IR-passing photographic filter, it is possible to see the Wood effect that consists of IR-glowing foliage. | What objects are notably bright in near IR? | {
"answer_start": [
852
],
"text": [
"Leaves"
]
} |
5a07c6570ff9ab00181693c0 | Infrared | The onset of infrared is defined (according to different standards) at various values typically between 700 nm and 800 nm, but the boundary between visible and infrared light is not precisely defined. The human eye is markedly less sensitive to light above 700 nm wavelength, so longer wavelengths make insignificant contributions to scenes illuminated by common light sources. However, particularly intense near-IR light (e.g., from IR lasers, IR LED sources, or from bright daylight with the visible light removed by colored gels) can be detected up to approximately 780 nm, and will be perceived as red light. Sources providing wavelengths as long as 1050 nm can be seen as a dull red glow in intense sources, causing some difficulty in near-IR illumination of scenes in the dark (usually this practical problem is solved by indirect illumination). Leaves are particularly bright in the near IR, and if all visible light leaks from around an IR-filter are blocked, and the eye is given a moment to adjust to the extremely dim image coming through a visually opaque IR-passing photographic filter, it is possible to see the Wood effect that consists of IR-glowing foliage. | What is the defined boundary between visible and infrared light? | {
"answer_start": [],
"text": []
} |
5a07c6570ff9ab00181693c1 | Infrared | The onset of infrared is defined (according to different standards) at various values typically between 700 nm and 800 nm, but the boundary between visible and infrared light is not precisely defined. The human eye is markedly less sensitive to light above 700 nm wavelength, so longer wavelengths make insignificant contributions to scenes illuminated by common light sources. However, particularly intense near-IR light (e.g., from IR lasers, IR LED sources, or from bright daylight with the visible light removed by colored gels) can be detected up to approximately 780 nm, and will be perceived as red light. Sources providing wavelengths as long as 1050 nm can be seen as a dull red glow in intense sources, causing some difficulty in near-IR illumination of scenes in the dark (usually this practical problem is solved by indirect illumination). Leaves are particularly bright in the near IR, and if all visible light leaks from around an IR-filter are blocked, and the eye is given a moment to adjust to the extremely dim image coming through a visually opaque IR-passing photographic filter, it is possible to see the Wood effect that consists of IR-glowing foliage. | At what wavelength does the human eye perceive red light? | {
"answer_start": [],
"text": []
} |
5a07c6570ff9ab00181693c2 | Infrared | The onset of infrared is defined (according to different standards) at various values typically between 700 nm and 800 nm, but the boundary between visible and infrared light is not precisely defined. The human eye is markedly less sensitive to light above 700 nm wavelength, so longer wavelengths make insignificant contributions to scenes illuminated by common light sources. However, particularly intense near-IR light (e.g., from IR lasers, IR LED sources, or from bright daylight with the visible light removed by colored gels) can be detected up to approximately 780 nm, and will be perceived as red light. Sources providing wavelengths as long as 1050 nm can be seen as a dull red glow in intense sources, causing some difficulty in near-IR illumination of scenes in the dark (usually this practical problem is solved by indirect illumination). Leaves are particularly bright in the near IR, and if all visible light leaks from around an IR-filter are blocked, and the eye is given a moment to adjust to the extremely dim image coming through a visually opaque IR-passing photographic filter, it is possible to see the Wood effect that consists of IR-glowing foliage. | What light is generated by an IR-passing photographic filter? | {
"answer_start": [],
"text": []
} |
5a07c6570ff9ab00181693c3 | Infrared | The onset of infrared is defined (according to different standards) at various values typically between 700 nm and 800 nm, but the boundary between visible and infrared light is not precisely defined. The human eye is markedly less sensitive to light above 700 nm wavelength, so longer wavelengths make insignificant contributions to scenes illuminated by common light sources. However, particularly intense near-IR light (e.g., from IR lasers, IR LED sources, or from bright daylight with the visible light removed by colored gels) can be detected up to approximately 780 nm, and will be perceived as red light. Sources providing wavelengths as long as 1050 nm can be seen as a dull red glow in intense sources, causing some difficulty in near-IR illumination of scenes in the dark (usually this practical problem is solved by indirect illumination). Leaves are particularly bright in the near IR, and if all visible light leaks from around an IR-filter are blocked, and the eye is given a moment to adjust to the extremely dim image coming through a visually opaque IR-passing photographic filter, it is possible to see the Wood effect that consists of IR-glowing foliage. | What objects are hard to see if all visible light leaks are blocked? | {
"answer_start": [],
"text": []
} |
5a07c6570ff9ab00181693c4 | Infrared | The onset of infrared is defined (according to different standards) at various values typically between 700 nm and 800 nm, but the boundary between visible and infrared light is not precisely defined. The human eye is markedly less sensitive to light above 700 nm wavelength, so longer wavelengths make insignificant contributions to scenes illuminated by common light sources. However, particularly intense near-IR light (e.g., from IR lasers, IR LED sources, or from bright daylight with the visible light removed by colored gels) can be detected up to approximately 780 nm, and will be perceived as red light. Sources providing wavelengths as long as 1050 nm can be seen as a dull red glow in intense sources, causing some difficulty in near-IR illumination of scenes in the dark (usually this practical problem is solved by indirect illumination). Leaves are particularly bright in the near IR, and if all visible light leaks from around an IR-filter are blocked, and the eye is given a moment to adjust to the extremely dim image coming through a visually opaque IR-passing photographic filter, it is possible to see the Wood effect that consists of IR-glowing foliage. | What value measures wavelengths as long as 1050? | {
"answer_start": [],
"text": []
} |
570b9002ec8fbc190045ba80 | Infrared | The concept of emissivity is important in understanding the infrared emissions of objects. This is a property of a surface that describes how its thermal emissions deviate from the ideal of a black body. To further explain, two objects at the same physical temperature will not show the same infrared image if they have differing emissivity. For example, for any pre-set emissivity value, objects with higher emissivity will appear hotter, and those with a lower emissivity will appear cooler. For that reason, incorrect selection of emissivity will give inaccurate results when using infrared cameras and pyrometers. | What is the term for the property that describes how a surface's thermal emissions deviate from the ideal of a black body? | {
"answer_start": [
15
],
"text": [
"emissivity"
]
} |
570b9002ec8fbc190045ba81 | Infrared | The concept of emissivity is important in understanding the infrared emissions of objects. This is a property of a surface that describes how its thermal emissions deviate from the ideal of a black body. To further explain, two objects at the same physical temperature will not show the same infrared image if they have differing emissivity. For example, for any pre-set emissivity value, objects with higher emissivity will appear hotter, and those with a lower emissivity will appear cooler. For that reason, incorrect selection of emissivity will give inaccurate results when using infrared cameras and pyrometers. | How will the infrared image of an object with a higher emissivity appear in relation to one with lower emissivity? | {
"answer_start": [
432
],
"text": [
"hotter"
]
} |
570b9002ec8fbc190045ba82 | Infrared | The concept of emissivity is important in understanding the infrared emissions of objects. This is a property of a surface that describes how its thermal emissions deviate from the ideal of a black body. To further explain, two objects at the same physical temperature will not show the same infrared image if they have differing emissivity. For example, for any pre-set emissivity value, objects with higher emissivity will appear hotter, and those with a lower emissivity will appear cooler. For that reason, incorrect selection of emissivity will give inaccurate results when using infrared cameras and pyrometers. | Along with pyrometers, what devices can receive inaccurate results if emissivity is not set correctly? | {
"answer_start": [
585
],
"text": [
"infrared cameras"
]
} |
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