Monthly Archives: September, 2009

What are prunes?

Prunes are dried plums, but all plums will not make prunes.  Prunes come from special kinds of sweet plums that can be dried without spoiling the fruit. Plums that are especially swell-suited for drying are called “prune plum.”  Prune plum are gathered from the ground after they have become so ripe that they can be …

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Where does platinum come from?

Perhaps you know someone who owns a ring with a platinum setting.  Platinum is a precious metal that looks like silver, but it is more valuable than gold. Its name comes from the Spanish word “platina”, which means “little silver”. Like silver and gold, it is usually mined in fairly pure form as little grains …

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How does a microscope work?

The word “microscope” comes from the Greek words for “small” and “see”.  A microscope is a device that tests you see very tiny things you can’t see with your eyes alone. The simplest kind is an ordinary magnifying glass.  A magnifying glass bends the light and spreads if to make things look bigger than they …

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What causes waves?

Water waves are caused mainly by the wind.  On a windy or stormy day there are many waves in the water, and on a calm day there are fewer waves. This explains what makes most waves in the water.  Winds push up waves on seas, lakes and ponds.  The waves you see on a calm …

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Why does iron rust?

An iron nail left in a damp places will soon be covered by rust.  The rusting of iron is an example of oxidation.  That is, when iron rusts, it actually “burns up”.  But the rusting process is very slow and does not produce heat fast enough to cause a flame. In this process, the iron …

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What is the difference between a cobweb and a spider web?

We are all familiar with the jumbled tangle of loosely woven webs that the common house spider spins in the nooks and crannies of our homes and other buildings.  People sometimes call these spider webs “cobwebs” when they have collected dust and dirt.  But actually, there is no difference between a cobweb and a spider …

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Why do we have leap years?

LEAP YEAR IS THE YEAR IN EVERY FOUR THAT HAS 366 DAYS INSTEAD OF 365.  THE EXTRA DAY IS ADDED TO FEBRUAY TO MAKE THE CALENDAR YEAR NEARLY THE SAME AS THE SOLAR YEAR. Leap year has 365 days, one more day than an ordinary year.  The calendar we use is based on the amount …

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Why are snakes used as the symbol of medicine?

The emblem of medicine is often pictured as a staff with a snake, or serpent, coiled around it. In the earliest days, the art of healing was practiced with much superstition and magic. The serpent was sacred to the ancient Greek as the symbol of health.  It was supposed to have great healing powers, since …

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