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/Tag: stars

What is electricity? Physics

By |2019-05-27T06:51:27-07:00August 16th, 2017|Physics|

What is electricity? A bolt of lightning in the sky What is electricity made of? Everything in the universe is made of atoms.  Those atoms are made of electricity. Atoms are made of even smaller particles called protons, neutrons, and electrons. Electricity is electrons that have gotten loose from their atom. More about electrons History of electricity What [...]

Medieval Islamic astronomy

By |2018-04-23T10:04:24-07:00July 27th, 2017|History, Islam, Science|

Islamic astronomers taking observations West Asian astronomers had been world leaders in astronomy for thousands of years before the Islamic conquests in the 600s AD. In the last centuries BC, West Asian astronomers had already figured out that the earth was a ball, and that the earth went around the sun, and how big the earth was, and that the moon went [...]

What is parallax? History of astronomy

By |2018-04-23T14:09:48-07:00July 18th, 2017|Greeks, Science|

Parallax and your finger Parallax comes from the Greek word "para", meaning "alternate" and "alla", meaning "change". Greek people used the word parallax to describe how an object seems to move when you look at it from two different places. The easiest way to see parallax in action is to hold out your left arm [...]

Ancient Greek astronomy

By |2019-07-23T23:51:59-07:00July 18th, 2017|Greeks, Science|

Greek astronomy: Eclipse of the sun Astronomy before the Greeks The art of astronomy was already very advanced before the Greeks began to interest themselves in the stars. The Egyptians and especially the Mesopotamians had done a lot of scientific observations and had named the constellations of stars, and many individual stars. Early African astronomy Egyptian [...]

What is an astrolabe? Greek science

By |2019-02-04T09:56:46-07:00July 16th, 2017|Greeks, Science|

An Islamic astrolabe (832 AD) Who invented the astrolabe? About 140 BC, the Greek astronomer Hipparchus of Rhodes invented the science of trigonometry. What's trigonometry?  Greek astronomy History of astronomy All our Ancient Greece articles Hipparchus figured out that you could use an imaginary right triangle whose corners were the sun, the earth, and the planets or stars, to calculate the movements [...]

What is metal? Chemistry

By |2018-04-24T14:46:23-07:00June 2nd, 2017|Chemistry|

Copper ore in Iran Metals are atoms that attach themselves to other atoms in a particular way. Metal atoms, because of how their electrons are arranged, lose their electrons easily. When they join up with other atoms to make molecules, metal atoms join together by exchanging electrons. Because metal atoms join other metal [...]

What is sulphur? Atoms, elements, chemistry

By |2017-06-02T17:25:58-07:00June 2nd, 2017|Chemistry|

Diagram of a sulphur atom Sulphur atoms fall near the middle of the scale: they are heavier than silicon but lighter than iron. Every atom of sulphur has 16 protons and generally 16 neutrons. Like silicon and iron, all atoms of sulphur are made inside stars that are getting older and have used [...]

What is the strong nuclear force? Atoms and Physics

By |2018-04-16T23:47:52-07:00June 2nd, 2017|Physics|

Diagram of an iron atom The protons inside the nucleus of an atom all have a positive electrical charge, so they push away from each other. But the strong nuclear force pulls the protons together. As you might think from the name, the strong nuclear force is very strong. It is stronger than [...]

What is silicon? Atoms, elements, chemistry

By |2018-04-24T14:46:23-07:00June 2nd, 2017|Chemistry|

Diagram of a silicon atom When a red giant star is getting older and runs out of helium fuel, it starts to convert the oxygen atoms in the star into silicon atoms. All silicon is made this way, inside a red giant star. Silicon is heavier than oxygen, because oxygen has only eight protons [...]