Speed of Light Air Density
As light moves from more dense, room temperature air to less dense, hot air, it changes speed and is bent, just as it would be by a lens.
|
|
|
|
|
This Week's Experiment - #237 Heat Waves?
I got the idea for this week's experiment while Lisa was making toast for
breakfast. Looking across the top of the toaster as it heated up, I noticed
the objects behind the toaster wavering in the heated air. It is one of
those things that most people have seen, but usually don't think much about.
Once you think about it, it really is an amazing thing to see. To experience
this, you will need:
a toaster, toaster oven, or some other heat source.
Warning! We will be using the toaster as a heat source. Be sure that you
have permission to use it and that an adult is around to help.
Place the toaster on a table or counter. Be sure that there is open space
all around it, so nothing gets burned or melted. Since we are going to be
using the toaster, you might as well make some toast at the same time, so get
some butter and jelly for afterwards.
Turn on the toaster. As it heats up, you should see that looking over the
top at objects across the room causes them to seem to wiggle and waver.
Why does it do that? It has to do with the speed of light. If you look up
the speed of light, you will find that it is 186,000 miles per second. If
you read carefully, you will see that it says that this is the speed of light
in a vacuum. It travels at different speeds when it is traveling through
other things, such as air, water or glass.
We are interested in what happens when light travels from one substance to
another. If the transition causes the light to change its speed, and if the
boundary between the two substances is at an angle that is not perpendicular
to the direction the light is traveling, the beam can be bent. This is the
basic idea behind how a lens works. As the light moves from the air to the
curved glass and then from the curved surface of the glass to the air again,
it is bent. This bending is necessary for things such as microscopes,
cameras, telescopes and eyeglasses to work.
What does all of this have to do with the toaster? As the toaster heats the
air around it, that air expands. This makes the air less dense and so it
begins to rise upwards. As light moves from the more dense, room temperature
air to the less dense, hot air, it changes speed and is bent, just as it
would be by a lens. The rising air does not form a smooth, bent surface as
it rises. Instead, the hot air swirls as it rises. As its surface ripples
and changes, the way that it bends the light also changes. This causes the
light passing through the hot air to waver and shimmer.
The same thing can often be seen in the hot air rising from a road in the
summer. This bending of the light by the hot air can make is seem that there
is a pool of water on the road. As your car gets closer, the pool of "water'
seems to disappear. It was not really water, but a mirage caused by the
bending of light. As a child, this always delighted me, and after all these
years, it still does. I may lose my hair (done that), my eyesight (new
glasses) and all sorts of other things, but I hope I never lose the joy that
I get from the marvels of the world around me.
These experiments are from Robert Krampf - The Happy Scientist
Education Posters at AllPosters.com | Clearance Posters
|
|
|
|
|
Nicholas Academy Index
|
|
Roman numerals, addition, multiplication, order of statehood, state and world capitals, order of presidents, chemical elements, parts of speech, spanish numbers.
|
Explore animation, filmmaking, build online cities, create and share works of art, write stories, create your own web site, read creativity articles.
|
Math games, quizzes, fun websites, printable charts, coloring books, tools. Algebra, geometry, fractions, multiplication.
|
Science games and quizzes, fun science websites, posters, coloring books, experiments, forensics labs and more.
|
Play language arts games, improve your vocabulary, create customized puzzles, make your own book! Download free software in the form of shareware, freeware, and demos.
|
|
Play music games, take free music lessons, explore music theory and history, find great posters.
|
Test your knowledge with these fast, fun, and educational quizzes. Roman numeral addition, world capitals, presidents in order, the elements, world flags, and more.
|
Templates, ideas for personal, educational, children's, business sites, design tips and tools, registration and hosting information, step-by-step instructions, quick and easy web page, web building just for kids.
|
Coloring books, countries of the world, games and quizzes, software downloads, posters, computer jigsaw puzzles, printables.
|
Science can be fun and understandable. Free Experiment of the Week, featuring experiments that are unusual, safe, dramatic, cheap, and fun. From Robert Kramp's Science Education Co.
|
|
Online, via email or through the regular mail. College, accredited high school, free reading and phonics courses, foreign language, history, religion, and more.
|
Arabic, German, Japanese, Spanish, French, Italian, Latin, Russian. Games, free software downloads, free online lessons, newspapers, discussion groups, articles, history, culture, quizzes.
|
Coloring books for kids and adults. Civil war, plants, animals, states, middle ages, cultures, geometric designs, puzzles.
|
Fun and affordable space items for kids, including toys, games, food products, and more.
|
New and used low cost books and textbooks. Websites with open source books and loan programs.
|
|
Artists, wars, armour, castle games, recipes, geography, quizzes, fashions, pictures of weapons, music, old world maps, women of medieval times, medicine, language, and more.
|
Reading systems, loan programs, flashcard, worksheet and test makers, game creators, board games, percentage calculator, puzzle creator, timeline template.
|
SAT, GED, ACT, practice tests, exam preparation. Standardized test practice, content standards listed by state, sample items, scope and sequence, aptitude, essential skills.
|
Parts of speech, civil rights, medieval, periodic table of elements, music, astronomy, world maps with flags, literature, poetry, biology,
|
Books, posters, videos, software, curriculum, courses. Save on teaching supplies, receive free educational materials.
|
|
|
