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The human body in medieval and modern science

By | 2018-04-25T17:09:55+00:00 September 6th, 2017|Biology, Science|

Chinese drawing of the organs (about 1200) Between the Middle Ages and modern times, doctors have learned a lot of new things about how human bodies work. The Islamic doctor Al-Tabari, in the early 800s, learned that light bounces off objects into your eyes. Al-Tabari's student Al Razi figured out that a fever is your body's way of fighting illness, not [...]

Earthquakes and algae – the planet Earth

By | 2018-05-31T11:49:27+00:00 August 18th, 2017|Physics|

Molten lava Most of the molecules that smashed together to make the Earth were iron. The smashing together released a lot of heat, so the whole center of the Earth is made of hot melted iron. Because iron is heavier than most other metals, it sank to the center of the Earth. Lighter molecules like silicon and [...]

Radioactivity and nuclear physics

By | 2018-04-24T14:44:18+00:00 August 17th, 2017|Physics|

A Japanese girl who lost her hair from radiation sickness from the atomic bomb Americans dropped on Hiroshima Some atoms are naturally radioactive, especially atoms of uranium and plutonium. These atoms have so many protons and neutrons that even the strong nuclear force is barely strong enough to hold them together, and they sometimes lose a proton or a [...]

What is a protein? Organic chemistry

By | 2017-06-02T23:46:07+00:00 June 2nd, 2017|Biology, Chemistry|

Proteins are a type of molecule made mainly out of hydrogen and carbon atoms. They are combinations of smaller molecules called amino acids. The first amino acids probably developed into proteins more than four billion years ago on Earth, possibly with the help of ribonucleic acid, or RNA. We don't know whether this process has happened on [...]

What is water made of? Molecules and chemistry

By | 2017-06-02T18:02:44+00:00 June 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 [...]

What is sulphur? Atoms, elements, chemistry

By | 2017-06-02T17:25:58+00:00 June 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 are hydrocarbons? Simple science – Chemistry

By | 2017-06-02T08:24:00+00:00 June 2nd, 2017|Chemistry|

A model of a methane molecule Hydrocarbons are molecules made out of hydrogen atoms and carbon atoms. Methane is the simplest hydrocarbon molecule: just one carbon atom with four hydrogen atoms stuck to it. Because both carbon and hydrogen were common in nebulae, hydrocarbon molecules are very common in space. Many of these molecules [...]