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Essay Galaxy - Holograms
Holograms
Toss a pebble in a pond -see the ripples? Now drop two pebbles close
together. Look at what happens when the two sets of waves combine -you get a
new wave! When a crest and a trough meet, they cancel out and the water goes
flat. When two crests meet, they produce one, bigger crest. When two troughs
collide, they make a single, deeper trough. Believe it or not, you've just
found a key to understanding how a hologram works. But what do waves in a
pond have to do with those amazing three-dimensional pictures? How do
waves make a hologram look like the real thing?
It all starts with light. Without it, you can't see. And much like the
ripples in a pond, light travels in waves. When you look at, say, an apple,
what you really see are the waves of light reflected from it. Your two eyes
each see a slightly different view of the apple. Th....
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