optics : light at work - part i. part 2 you can order free dvds from spie : light in action : lasers, cameras & other cool stuff ; optics : light at work ; and careers in optics. & optics : science and art closer than you think optical technology and the study of light go far back in human culture. contemporary artists are often quick to adopt new technology, or to absorb its implications. was it any different then? why should the use of a tool diminish the value of the art? of light and color a set of interactive java applet tutorials to help you understand how color and light work. beautifully done. lots of levers to slide to make changes. from molecular expressions. here you ' ll find pictures, videos, games, educational materials, and more. a fun way to learn all about the " cool " part of the electromagnetic spectrum : infrared light. this site is dedicated to light in all its manifestations : in physics, in technology, in nature and in culture. to help you learn about light, we ' ve included a message board for posting questions. a thinkquest site. system of web pages about light light is great, light is mysterious, light is useful. after all, they say everything started with light. when any revolution has happened in the history of science, light was always there. so it deserves a little attention. here on earth the speed of light can change. how? go to joe ' s room and see if you can figure it out. an interactive tour of current research in the materials sciences at berkeley lab ' s advanced light source. for high school students, this site explains how intense light is used for physics research. for kids : science and engineering some fun and interesting things about optics : the science of light, and one of the most important fields of physics. by bruce irving, optical research associates. - light without heat to do this experiment, you ' ll need some light sticks from a sporting goods store or a necklace from a fair. you ' ll watch what happens when you put it in hot water and in your refridgerator.. from experiments by professor shakhashiri. how fireflies produce light via a chemical reaction and how you can attract fireflies to your yard, if you have them in the area in the first place. colors in a green leaf using chromatography to help you understand just how leaves change colors in the fall and why some trees change to red while others change to orange or yellow, try this experiment on leaves


connected knowledge : science, philosophy, and education oxford university press ( 1997 ) | abstract | | when physicist alan sokal recently submitted an article to the postmodernist journal social text, the periodical ' s editors were happy to publish it - - for here was a respected scientist offering support for the journal ' s view that science is a subjective, socially constructed discipline. but as sokal himself soon revealed in lingua franca magazine, the essay was a spectacular hoax - - filled with scientific gibberish anyone with a basic knowledge of physics should have caught - - and the academic world suddenly awoke to the vast gap that has opened between the scientific community and their mould - be critics. but the truth is that not only postmodern critics but americans in general have a weak grasp on scientific principles and facts. in connected knowledge, physicist alan cromer offers a way to bridge the chasm, with a lively, lucid account of scientific thinking and a provocative new agenda for american education. science, cromer argues, is anything but common sense : it requires a particular habit of mind that does not come naturally. for example, something as simple as buoyancy can only be explained through archimedes ' principle - - that a body in a fluid is subject to an upward force equal to the weight of fluid it displaces - - yet few scientists could arrive at this ancient concept by trial and error. school children, however, are often given a ball and a tank of water, and asked to explain buoyancy any way they can. today ' s de emphasis on teaching pupils necessary facts and principles, he argues, " far from empowering them, makes them slaves of their own subjective opinions. " this movement in education, known as constructivism, has close ties to postmodern critics ( such as the editors of social text ) who question the objectivity of science, and with it the existence of an objective reality. cromer offers a ringing defense of the knowability of the world, both as an objective reality and as a finite landscape of discovery. the advance of scientific knowledge, he argues, is not unlike the mapping of the continents ; at this point, we have found them all. he shows how the advent of quantum mechanics, rather than making knowledge less certain, actually offers a more precise understanding of the behavior of atoms and electrons. turning from philosophy to education, he argues that instead of allowing students to flounder, however creatively, schools should follow a progressive curriculum that returns theoretical knowledge


metamorphic rocks and minerals this activity was selected for the on the cutting edge reviewed teaching collection this activity has received positive reviews in a peer review process involving five review categories. the five categories included in the process are - scientific accuracy - alignment of learning goals, activities, and assessments - pedagogic effectiveness - robustness ( usability and dependability of all components ) - completeness of the activitysheet web page for more information about the peer review process itself, please see http : / / serc. carleton. edu / nagtworkshops / review. html. this page first made public : aug 7, 2006 this exercise is an introduction to the most important metamorphic rocks and minerals. this exercise is designed for a mid / upper - level undergraduate geology course on the principles of mineralogy. skills and concepts that students must have mastered students should have knowledge of basic chemistry and of minerals equivalent to what they would learn in an introductory geology class. how the activity is situated in the course this activity is the 19th of 36 mineralogy exercises and is used around the middle of the course. content / concepts goals for this activity - learn to identify key metamorphic minerals and rocks in hand specimen and thin section. higher order thinking skills goals for this activity - identify key properties useful for mineral identification. other skills goals for this activity description of the activity / assignment in this three - part exercise, students study hand samples and thin sections of important metamorphic rocks and minerals. - part one - box of rocks : students examine trays of metamorphic rocks and minerals and record their physical properties, composition, and habit. they note chemical and physical similarities and differences and identify the rock samples and minerals they contain. - part two - definitions : define a list of terms relevent to the lab. - part three - minerals in thin section : observe minerals in thin section and answer questions about them.


well it ’ s been quite a while, but i think i can carve out the time to move forwards again. i was all set to start with lie algebras today, only to find that i ’ ve already defined them over a year ago. so let ’ s pick up with a recap : a lie algebra is a module — usually a vector space over a field — called and give it a bilinear operation which we write as. we often require such operations to be associative, but this time we impose the following two conditions : now, as long as we ’ re not working in a field where — and usually we ’ re not — we can use bilinearity to rewrite the first condition : so. this antisymmetry always holds, but we can only go the other way if the character of is not, as stated above. the second condition is called the “ jacobi identity ”, and antisymmetry allows us to rewrite it as : that is, bilinearity says that we have a linear mapping that sends an element to a linear endomorphism in. and the jacobi identity says that this actually lands in the subspace of “ derivations ” — those which satisfy something like the leibniz rule for derivatives. to see what i mean, compare to the product rule : where takes the place of, takes the place of, and takes the place of. and the operations are changed around. but you should see the similarity. lie algebras obviously form a category whose morphisms are called lie algebra homomorphisms. just as we might expect, such a homomorphism is a linear map that preserves the bracket : we can obviously define subalgebras and quotient algebras. subalgebras are a bit more obvious than quotient algebras, though, being just subspaces that are closed under the bracket. quotient algebras are more commonly called “ homomorphic images ” in the literature, and we ’ ll talk more about them later. we will take as a general assumption that our lie algebras are finite - dimensional, though infinite - dimensional ones absolutely exist and are very interesting. and i ’ ll finish the recap by reminding you that we can get lie algebras from associative algebras ; any associative algebra can be given a bracket defined by the above link shows that this satisfies the jacobi identity, or you can take it as an exercise.