Why Do Frogs Croak?
Why Do Frogs Croak? In most species of the frogs only the males croak. The male frog croaks in order to attract the female frog during the mating season. When a frog is...
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When Were the First Hot-air Balloons Flown?
When Were the First Hot-air Balloons Flown? There was much excitement in France on September 19, 1783. The Montgolfier brothers were going to attempt to send a big...
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What Is an Internal Combustion Engine?
What Is an Internal Combustion Engine? An internal combustion engine is a heat engine where the combustion of a fuel occurs with an oxidizer (usually air) in a...
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Who Invented the Radio?
Who Invented the Radio? Radio owes its development to two other inventions—the telegraph, and the telephone. In fact, all three technologies are closely related. Few...
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Why Can I See My Breath on a Cold Day?
Why Can I See My Breath on a Cold Day? On a cold day you can see a small steamy cloud each time you blow out your breath. Your breath has moisture in it. Air is warmed...
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