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Why is the sky blue? Weather science

By | 2017-08-20T23:42:12+00:00 August 20th, 2017|Physics|

Blue sky with cirrus clouds This is an easy question to ask but the answer is pretty hard. The light that comes from the Sun to Earth looks white, but really it is made up of all different colors of light mixed together. You can see this by using a glass of water or a glass prism to break up [...]

Where do tornadoes come from? – Weather – Earth science

By | 2017-08-20T23:36:54+00:00 August 20th, 2017|Physics|

A tornado wrecked a town in northern France When there's wind coming from more than one direction at the same time, sometimes the air begins to spin around in one place. This is especially likely when a hot, wet wind coming from the south hits a cold, dry wind coming from the north. Both winds [...]

Stratus clouds – A blanket of cloud – Weather science

By | 2017-08-20T18:32:08+00:00 August 20th, 2017|Physics|

Stratus clouds (thanks to NASA) If you see stratus clouds, that's the time to get inside and stay there. Stratus clouds mean rain if it is warm and snow if it is cold. They look like a huge gray blanket that hangs low in the sky. Sometimes stratus clouds are on the ground or very near the ground, [...]

What is snow? Weather – Earth science

By | 2017-08-20T18:28:39+00:00 August 20th, 2017|Physics|

If it's colder, rain may fall as snow. About two and a half billion years ago, the Earth finally cooled down enough for it to snow for the first time. Most of the time since then, the Earth has been warm enough that it didn't snow at all. But from time to time, the Earth becomes cooler, entering [...]

What causes the seasons? Earth science

By | 2017-08-20T18:16:08+00:00 August 20th, 2017|Physics|

This is why it's hotter in summer and colder in winter. The reason it is sometimes winter and sometimes summer is that the Earth spins on a slightly tilted axis. You can see the red axis in the picture here (though really there is no axis to see; it's a direction, not a real stick). [...]

Why does it rain? Weather – Earth science

By | 2017-08-20T18:07:53+00:00 August 20th, 2017|Physics|

Thanks to Rocbike for the great picture! When the Earth first formed, about 4.5 billion years ago, it didn't rain here. Until about four billion years ago, Earth was too hot for raindrops to form, and water just hung in the air as steam without falling as rain. Then as the Earth's surface began to cool, in the Archaean era, huge clouds formed and began [...]

Nimbus clouds – Rain clouds – Weather

By | 2017-08-20T17:52:32+00:00 August 20th, 2017|Physics|

Cumulonimbus clouds Nimbus clouds often mean that a thunder storm is brewing: there may soon be thunder and lightning. Get out of the swimming pool! Nimbus is a fancy word, but it really just means a cloud that already has rain or snow falling out of it. Can you see the rain falling in the picture to the right? Clouds don't [...]

What makes thunder and lightning? – Weather science

By | 2017-08-20T17:49:37+00:00 August 20th, 2017|Physics|

A bolt of lightning in the sky Hot air and cold air are constantly moving around the Earth, as the hot air rises and the cold air sinks - that's what makes wind. Sometimes as this airmoves around, it gets more exciting than just wind, though. A thunderstorm begins when the wind picks up a lot of water from the [...]

Why does earth have weather? – Earth Science

By | 2017-08-20T17:40:27+00:00 August 20th, 2017|Physics|

A thunderstorm in South Africa The weather on Earth happens because of the evaporation and condensation of water, and because of the spinning of the earth and the tilt of the earth on its axis. Does it seem strange that such quiet things could cause big thunderstorms and huge waves and blizzards? Here's why. Because the Earth is tilted on its axis, [...]

What are hurricanes? Weather science

By | 2017-08-20T17:36:24+00:00 August 20th, 2017|Physics|

A hurricane in Cuba A hurricane (also called a typhoon or a cyclone) is basically a huge wind. Hurricanes form in the summer and especially in the fall, because they can only form where there is cold air high over warm ocean water. Hurricanes form near the equator, because that's the only place where ocean water gets warm [...]