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Why is the sky blue? Weather science

By |2017-08-20T23:42:12+00:00August 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 |2018-05-31T11:49:23+00:00August 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 [...]

What is snow? Weather – Earth science

By |2018-04-24T14:32:37+00:00August 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 |2018-04-24T15:45:14+00:00August 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+00:00August 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 [...]

Why does earth have weather? – Earth Science

By |2017-08-20T17:40:27+00:00August 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’s the equator? Geography and the Earth

By |2018-04-12T08:53:24+00:00August 20th, 2017|Physics|

This globe shows the equator running around the widest part of the Earth. The equator is an imaginary line running around the widest part of the Earth, halfway between the North Pole and the South Pole. So if you are north of the Equator, you're in the Northern Hemisphere. And if you're south of [...]

What are planets? Astronomy – Space science

By |2018-09-10T17:46:23+00:00August 19th, 2017|Physics|

What are planets? The planet Venus from space Before there were planets For several hundred million years after the Big Bang, there were no planets, only stars. Planets couldn't form until the first stars ran out of fuel and exploded into supernovas, about 14 billion years ago. The supernovas spewed out thousands of tons of carbon, oxygen, iron and other elements into space. Planets [...]

The Moon – Astronomy – Physics

By |2018-05-31T11:49:27+00:00August 19th, 2017|Physics|

Earth's moon (about 239,000 miles from Earth) (That's almost ten times as far as going all the way around the Earth) Nobody knows exactly how the moon formed, but this is one possibility. After the planet Earth formed (along with the other planets), about four and a half billion years ago, during the Hadean Eon, there were [...]

Meteors – Shooting stars – Astronomy

By |2018-05-31T11:49:25+00:00August 18th, 2017|History|

Lyrid meteor shower Meteors or meteorites are bits of rock (like granite) and ice - usually a mixture of rock and iron and nickel but sometimes just rock or just iron - from out in space that get sucked into the gravity of the Earth and fall through our atmosphere to the ground. Usually this is because a comet has passed close enough to the Earth for [...]