Reflecting Light Beams
Why does light travel so well inside water, even when the stream is bent?
|
|
|
|
|
|
This Week's Experiment - #302 Fiber Optic Water
Today we put on Christmas music and decorated our Christmas trees. Yes, I
said trees. We have two this year. One is a normal, green tree. The
other is a silver tree with fiber optic lights. It changes colors and
twinkles. As we were decorating, Lisa asked about the fiber optics, which
led to this week's experiment. To explore fiber optics, you will need:
a metal food can
a hammer and nail
water
a flash light
Open the can and empty it. I used a can of peaches, which Lisa and I
enjoyed as a snack. Rinse the can and use the nail to punch a hole in the
bottom of the can. Check to be sure that the hole does not have sharp
edges. Working over the sink, put your finger over the hole, and fill the
can with water. Have someone turn off the lights for you. Turn on the
flashlight and aim the beam down into the can of water. Remove your finger
from the hole and look carefully at the stream of water. You should be able
to see the light shining through the water. If not, move the flashlight a
bit until you can.
Place your finger in the stream of water. What do you see? There is a
bright dot of light on your finger where the water hits. This is light that
is traveling down the stream. As the water level drops, you can tilt the
can so that the stream goes out to the side, bending down. Even with the
stream of water bending, you should be able to see the spot of light on your
finger, as long as it is fairly close.
Why does the light travel so well inside the water, even when the stream is
bent? Darken the room again. Hold your finger over the hole and fill the
can with water. This time, hold the flashlight about 6 inches above the
water and slightly to the side. Shine the beam on the water and look at the
ceiling. There is a spot of light up there! It is reflecting from the
water. When the light hits the surface of the water, some of it passes
through, but some of it is reflected. If you had a waterproof flashlight
and a very large container of water, you could hold the flashlight
underwater, with the beam shining upwards towards the surface. Again, the
surface would reflect some of the light, this time with the beam reflecting
back into the water.
While we are talking about reflecting, imagine for a minute what would happen
if you had a long tube-shaped mirror, with the mirror surface on the inside.
If you directed the beam of the flashlight into the tube, the light would
reflect from one side and then the other, bouncing around until it reached
the other end of the tube. This would work, even if the tube was bent.
The same thing happens with the stream of water. When you shine the light
into the can, some of it goes into the water flowing from the hole. When
the light hits the side of the water stream, most of it reflects back, just
as it would in our imaginary mirror tube.
Real fiber optics are long plastic fibers that look like clear fishing line.
The plastic is very clear, letting the light pass through easily. The
sides of the fiber act very much like the sides of the water stream,
reflecting the light back and forth inside. Fiber optics are used for many
things besides high tech Christmas trees. They are used to carry all sorts
of information, from computer data to telephone conversations. Instead of
transmitting these as electrical impulses through wires, they are sent as
pulses of light, though the optical fibers.
If you don't want to go to all the trouble of punching holes in cans, you can
do the experiment with just a faucet and a flashlight. Turn on the water to
form a thin, constant stream. Hold your finger in the stream, about 4
inches below the faucet. Shine the beam of the flashlight onto the stream,
from the side. You can even direct the beam upwards at an angle. You
should still see a dot of light where the water hits your finger. It will
not be as bright as with the can, but it should be bright enough for you to
see in a darkened room.
Well, I have to wind this up now, as Mawra the cat is rearranging the
decorations on the tree. Have a good week.
From Robert Krampf's Science Education Company
PO Box 60982
Jacksonville, FL 32236-0982
904-388-6381
krampf@aol.com
|
|
|
|
Nicholas Academy Index
|
|
Artists, wars, armour, castle games, recipes, geography, quizzes, fashions, pictures of weapons, music, old world maps, women of medieval times, medicine, language, and more.
|
Arabic, German, Japanese, Spanish, French, Italian, Latin, Russian. Games, free software downloads, free online lessons, newspapers, discussion groups, articles, history, culture, quizzes.
|
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.
|
Math games, quizzes, fun websites, printable charts, coloring books, tools. Algebra, geometry, fractions, multiplication.
|
Play music games, take free music lessons, explore music theory and history, find great posters.
|
|
Explore animation, filmmaking, build online cities, create and share works of art, write stories, create your own web site, read creativity articles.
|
Science games and quizzes, fun science websites, posters, coloring books, kits, experiments, forensics labs and more.
|
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.
|
Fun and affordable space items for kids, including toys, games, kits, food products, and more.
|
|
Educational science kits kids will love! Early science kit, DNA explorer kit, robot challenge, forensic lab, volcano kits, crystals.
|
All in one project labs, light kits, sound kits, motion and metal detectors, clap on/off kit, nerve tester and shocker.
|
Civil rights, African American writers, parts of speech, medieval, periodic table of elements, music, astronomy, world maps with flags, literature, poetry, dinosaurs, biology, cats, Japanese anime.
|
Coloring books for kids and adults. Civil war, plants, animals, states, middle ages, cultures, geometric designs, puzzles.
|
Online, via email or through the regular mail. College, accredited high school, free reading and phonics courses, foreign language, history, religion, and more.
|
|
Test your knowledge with these fast, fun, and educational quizzes. Roman numeral addition, world capitals, presidents in order, the elements, world flags, and more.
|
Roman numerals, addition, multiplication, order of statehood, state and world capitals, order of presidents, chemical elements, parts of speech, spanish numbers.
|
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.
|
New and used low cost books and textbooks. Websites with open source books and loan programs.
|
|
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.
|
Books, posters, videos, software kits, curriculum, courses. Save on teaching supplies, receive free educational materials.
|
This site map lists nearly every page on our site, along with a short description.
|
|
|
|
Educational Poster Store
Hundreds of educational posters in different subject areas. Parts of speech, medieval, solar system, biology, world maps, Einstein, Martin Luther King. Science, math, literature, art, music, english, geography, social studies. If you don't know exactly what you're looking for, this is great to browse for ideas.
|
NASA Website Links
Educational resources include worksheets such as mazes, coloring pages, shuttle model instructions, crossword puzzles, space food tray instructions and grocery list, and more. See the Space Station Sky Watch, view a NASA Astronaut Application or the Space Shuttle Launch Schedule, learn about the U.S. Space Camp and Women in Spaceflight.
|
Zoobooks
Get a free Zoobooks issue and a tiger poster. Zoobooks are the all-in-one, everything-you-wanted-to-know but-didn’t-know-who-to-ask guide to the world’s most fascinating animals, birds, reptiles, and insects. For kids five to twelve.
|
|
