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What is snow? Weather – Earth science

By |2018-04-24T14:32:37-07:00August 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 [...]

Why does it rain? Weather – Earth science

By |2017-08-20T18:07:53-07:00August 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 [...]

Nimbus clouds – Rain clouds – Weather

By |2018-11-09T06:53:08-07:00August 20th, 2017|Physics|

Cumulonimbus clouds are a type of nimbus cloud What is a nimbus cloud? Nimbus clouds often mean that a thunder storm is brewing: there may soon be thunder and lightning. Get out of the swimming pool! What causes thunderstorms? Other kinds of clouds More about weather Nimbus is a fancy word, but it really just means [...]

Inuit history – Native Americans

By |2018-04-24T09:52:08-07:00August 9th, 2017|History|

Inuit carving of a sea lion The early Inuit The Inuit lived along the eastern coast of Siberia and in Alaska, on both sides of the Bering Strait. (Some people call them the Eskimo, but that's an insulting Algonquin word for them). The Inuit fished and hunted seals and walruses and caribou. Inuit trade with [...]

Inuit houses – Igloos

By |2018-04-07T17:05:24-07:00August 7th, 2017|Architecture, Native American|

An Inuit village in 1575 AD Most of the time, most Inuit people lived in wooden houses built near the coast, where they could get to their fishing boats easily. They built their houses out of driftwood that washed up on the beach, and covered them with dirt to keep them warm. There was not [...]

Who was Anaxagoras? Greek scientist

By |2019-01-26T12:15:15-07:00July 18th, 2017|Greeks, Science|

Anaxagoras came from Clazomenae: A map showing Clazomenae Where was Anaxagoras from? Like Thales before him, Anaxagoras was born in what's now Turkey. Anaxagoras was born around 500 BC in a city called Clazomenae, in the Persian Empire. When he was a child, Clazomenae participated in the Ionian Revolt and soon became part of the Athenian Empire. Who was Thales? More [...]

Ancient Greek weather

By |2018-04-22T18:44:29-07:00July 6th, 2017|Environment, Greeks|

Greek weather and environment: a map of Greece The weather in ancient Greece, like the weather in most places, changed with the seasons. Greek weather also depended on whether you were in Northern Greece (near Thermopylae) or in Southern Greece (near Sparta). In the spring, it would be pretty rainy, especially in Northern [...]

Early European environment: northern Europe

By |2019-05-29T18:18:54-07:00June 27th, 2017|Environment, Northern Europe|

Black Forest in Northern Europe: the early European environment had a lot of forests like this one. Not so different from Central Asia When people first arrived in northern Europe and Scandinavia, following the Danube inland from Central Asia, they found an environment that must have already been familiar to them: a lot [...]

Where are the Himalaya Mountains? India

By |2018-04-21T11:56:45-07:00June 25th, 2017|China, Geology, India|

Himalaya Mountains About 55 million years ago, plate tectonics made the land that is now India break off from what is now Africa. At this time, the first modern mammals like rats and guinea pigs were evolving, and most of the Earth was covered in forests. For five million years India floated slowly [...]

What is water made of? Molecules and chemistry

By |2017-06-02T18:02:44-07:00June 2nd, 2017|Chemistry|

A big ocean wave The first molecules of water formed out in space, about 14 billion years ago, as part of the nebula left over after an early star exploded in a supernova. There were a lot of hydrogen and oxygen atoms floating around in these nebulae, and when they stuck together that [...]