Diffraction Fringe Light Waves Particles Photons Thomas Young
Light is a strange thing. In some ways, it acts as if it is made of tiny particles. In other ways, it acts as if it is made up of waves.
|
|
|
|
|
This Week's Experiment - #258 Dark Lines
This week, we are going to take another look as something that we looked at a
few weeks back in #252 Bubble Colors. Then we saw how light waves could
cancel each other to produce the colors we see in a soap bubble. In that
experiment, we only canceled out part of the light, removing some colors so
we could see others. This time, we are going to cancel it entirely! You
will need:
your fingers
a bright light
Sit a few feet away from the light. Hold your hand up in front of your face,
with your fingers held out straight. If you look, you will see that there
are open gaps between your fingers. Start with your hand about an inch away
from your eye, looking at the light through one of these gaps. Slowly move
your hand away from your face. You should begin to see dark stripes or bands
inside the gap. If you have trouble seeing them, squeeze your fingers closer
together or move them a little apart, until they are easy to see.
These lines are called diffraction fringe. What causes them? As the light
moves through the slit between your fingers, it bends and begins to spread
outwards. This is called diffraction. As the light spreads, the light waves
meet each other and something wonderful happens.
Picture waves in water as they meet each other. Each wave has a part that is
up (the crest) and a part that is down (the trough). If both waves are up
when they come together, they add their heights and you get a very high crest
as they meet. If both are down, you get a very deep trough. But what
happens if one is up and the other is down? They cancel each other out and
you get flat water. In this case, instead of flat water, you get dark areas.
This experiment is based on the work of Thomas Young. He was an English
scientist who in 1820 used a similar experiment in his study of light. Light
is a strange thing. In some ways, it acts as if it is made of tiny
particles. In other ways, it acts as if it is made up of waves. This
experiment is an example of light acting as waves. If two particles hit each
other, they don't both vanish. The only way that Thomas Young could think of
that two beams of light could meet and cancel each other out was if light was
made up of waves.
In Young's time there were bitter arguments between scientists, with some
saying that light was made or particles and others saying that light was made
of waves. Now we take a much more practical approach. We say that light is
made of photons, which can act like particles in some ways and like waves in
others. That leaves more time to argue about other puzzles in science.
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.
|
|
|
