/Tag: planets

What is centrifugal force? Physics definitions

By |2019-03-11T05:58:01-07:00August 16th, 2017|Islam, Physics|

Kids playing tetherball using centrifugal force Who first explained centrifugal force? When something is going straight, it always keeps going straight unless something else stops it or turns it. (The Iranian scientist Ibn Sina figured this out about 1000 AD). Who was Ibn Sina? Medieval Islamic science All our physics articles An example of centrifugal [...]

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 [...]

Area of a sphere – Volume of a sphere

By |2017-07-29T13:10:50-07:00July 29th, 2017|Math|

This is a sphere. A sphere is a three-dimensional circle. Or you could say that a sphere is the set of all the points that are at the same distance from the center of the sphere. In nature, centrifugal force and gravity tend to make a lot of things into spheres: soap bubbles, for instance, atoms, and planets. The radius of a sphere [...]

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 [...]

Hadean Eon – Earth, Moon, proteins, RNA

By |2019-07-31T13:18:23-07:00June 24th, 2017|Geology|

In the Hadean Eon, Earth was covered with active volcanoes like this one. Why is it called the Hadean Eon? Scientists named the Hadean Eon after the Greek god Hades, who ruled the underworld. That's because during most of the Hadean period the surface of the Earth must have been like the Christian [...]

Earthquakes, tsunamis, and the Richter scale

By |2019-02-05T06:11:50-07:00June 23rd, 2017|Geology|

Earthquake in Peru - Earthquakes can split the ground open! What causes earthquakes? What causes earthquakes? Earthquakes happen when the moving tectonic plates that make up the surface of the Earth move apart or bump into each other, or slide under each other. This movement tears apart the surface of the Earth, or crunches [...]

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 [...]