How Is Coal Formed?
How Is Coal Formed? Coal comes from plants that have been buried in the earth so long, they turned hard and black. Millions of years ago, much of the earth was swampy...
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Why Do We Have Time Zones?
Why Do We Have Time Zones? Time is not same everywhere. When it is noon in New York, for example, it is still 9 a.m. in San Francisco. The sun seems to move across the...
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How Do Clouds Move in the Sky?
How Do Clouds Move in the Sky? Clouds are formed when water evaporates from rivers, ponds, oceans, and lakes. The tiny droplets of water cling to particles like (dust,...
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What Are a Statute and a Nautical Mile?
What Are a Statute and a Nautical Mile? The statute mile is a unit for measuring distance on land. It is equivalent as we all know, to 1760 yards or 5280 feet. The...
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What Is Gravity?
When you toss a ball into the air, it comes down because it is pulled to earth by gravity. Gravity is a force that pulls all things on the earth toward the...
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