Monthly Archives: April, 2010

How does a pipe organ work?

Of all the musical instruments, pipe organs are the biggest.  Pipe organs may have hundreds or even thousands of pipes in them. The sound of the pipe organ is produced by letting air into sets of pipes.  The pipes are all of different lengths and sizes. The longest pipe make the deepest note, the shortest …

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How does radar work?

Almost everyone has heard echoes.  When you shout toward a cliff, the sound waves of your voice bounces back as an echo. Radar works in much the same way.  It is an electronic device that can detect distant objects by bouncing radio waves off of them and listening for echoes. Objects such as airplanes and …

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What is coral?

Coral is hard, rocky material formed in the sea from the limestone skeletons of many tiny sea creatures called coral polyps (pronounced PO Lips). A coral polyp builds its limestone skeleton around its soft body.  The limestone is made from chemicals present in sea water. Only the polyp’s mouth and tentacles reach out of the …

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How do mushrooms grow?

Mushrooms often seem to appear as if by magic in a meadow after a rainy summer day. The most familiar kinds look like little umbrellas.  Others may resemble bells, funnels, or pieces of coral. Mushrooms belong to a group of plants called fungi.  There have neither flowers nor seeds.  New plants start from tiny cells …

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What are infrared rays?

Infrared rays are waves of invisible radiant energy, like the visible waves of sunlight that travel, or radiate from the sun. Infrared rays the lie outside the visible spectrum at its red end.  These rays are “redder” than the reddest light our eyes can see, so they are called infrared, meaning “below the red.” Infrared …

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What is a pitcher plant?

The pitcher plant is a curious plant that traps insects in its pitcher like leaves.  A liquid inside the leaves drown them and helps di them. Everyone expects insects to eat plants.  But did you know that there are plants that eat insects?  One of these is the pitcher plant. This curious plant is found …

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What does a walrus use its tusks for?

A walrus is a large seallike animal that lives in the cold North, near the edge of the polar ice. A walrus can be most easily recognized by its white, daggerlike tusks that never stop growing.  The tusks are really two overgrown teeth that curve downward from the mustached upper tip. Some walruses have tusks …

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What is an oasis?

An oasis is a place in the desert where a spring or well furnishes enough water to allow plants to grow. In the desert it hardly ever rains, so there is very little water and few plants and animals.  But even in the driest desert, you can sometimes see an island of green, where trees …

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How are underwater tunnels built?

Some underwater tunnels are made from giant tubes that are built on land, then such in a deep trench dug in the river bottom. It is sometimes better to tunnel under a river than to build a bridge across it. Building an underwater tunnel is more difficult than boring a tunnel through a mountain.  In …

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