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Main sequence stars – Astronomy

By |2018-05-31T11:49:32+00:00August 18th, 2017|Physics|

Main sequence stars: A starry sky with the Milky Way galaxy (thanks to Bernd Nies) What is a main sequence star? Nine out of ten stars that you see in the sky are main-sequence stars, and our sun is one of them. (More about the sun) Most main-sequence stars probably started out as brown dwarfs, and then succeeded [...]

Big bang – Space science – Physics

By |2018-04-24T14:22:12+00:00August 17th, 2017|Physics, When|

Inside stars (like our Sun) there are fusion reactions. Stars got started after the Big Bang. The Big Bang was the very beginning of our Universe, and it probably happened about 13.73 billion years ago, because that's how old the oldest stars are, and we think that stars began to form almost immediately after the Big Bang. Nobody [...]

Nuclear fusion project – Physics

By |2018-05-31T11:49:26+00:00August 17th, 2017|Physics|

Build your own model of a fusion reaction: start with a regular red lego (a proton). Wrap a rubberband around it to be the strong nuclear force. Then connect a small blue lego (an electron) to the red lego to make a hydrogen atom. Make four of these hydrogen atoms. Now imagine that your hydrogen atoms are being heated up [...]

What is work? Physics definitions

By |2018-05-31T11:49:15+00:00August 17th, 2017|Physics|

Ancient Egyptian cattle plowing (Louvre Museum, Paris) You might think you know what work is, like homework, or having to pick up your room, right? But to scientists, work has a more definite meaning: work is force x distance. That means that you can measure work by measuring how much force, or energy, [...]

What is friction? Physics definitions

By |2018-05-31T11:49:28+00:00August 16th, 2017|Physics|

Hands rubbing together is a kind of friction Friction is what happens when any two things rub against each other. These can be solid things, like your two hands rubbing together, or your skis rubbing on the snow, or a hammer hitting a nail, or they can be gases, like friction with the air slowing down your car, or [...]

Emilie du Chatelet – European philosophy

By |2018-04-08T11:14:27+00:00August 7th, 2017|Modern Europe, Philosophy|

Emilie du Chatelet, a French philosopher in the 1700s Emilie du Chatelet's rich father, who was interested in literature and science, hired tutors to homeschool her, instead of sending her to a convent school. She learned Latin, German, Greek, and Italian, as well as math and science. When du Chatelet was 18, she married [...]

What is heat? Simple science – Chemistry

By |2018-05-08T09:27:54+00:00June 2nd, 2017|Chemistry, Physics|

What is heat? A big campfire throws some serious heat Definition of heat When molecules of any kind of atoms get more energy in them than they had before, they move faster, and we call that "heat". When the molecules move faster, they hit against each other and bounce apart, and so they [...]