Why Do Stars Blink or Twinkle?
Stars blink or twinkle when we observe them (from the surface of the earth) because we are viewing them through different layers of turbulent (swirling) air and...
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How Can You Tell What Time It Is by Looking at the Sun?
How Can You Tell What Time It Is by Looking at the Sun? We know that the Sun moves across the sky during the day. Probably the simplest way to tell time is by knowing...
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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 Causes the Ring Around Moon?
What Causes the Ring Around Moon? We can sometimes see a big ring of light around the moon. A ring around the moon is caused when the moon shines on thin clouds made of...
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How Does a Sundial Tell Time?
How Does a Sundial Tell Time? Long before we had clocks, people used sundials to tell time. A sundial tells time by measuring the angle of a shadow cast by the sun. A...
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