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Physics, Astronomy & Cosmology / What do atoms consist of?

« on: 18/01/2009 11:59:47 »

Nicholas - welcome to TNS.

Protons & neutrons form the nucleus of an atom. Protons carry positive charge and neutrons, as the name suggests, are neutral. The vast majority of the mass of the atom is contained within the nucleus.

Protons & neutrons are made of quarks (not perks). There are 6 types of quark but protons & neutrons comprise only 2 - the up quark & the down quark. Neutrons have 2 downs & 1 up, protons have 2 ups & 1 down. These quarks carry different charge. The up quark's charge is +2/3 and the down quark's is -1/3.

You can see that by adding these in the appropriate combinations you get +2/3 * 2 -1/3 = 1; a proton with charge 1 or -1/3 * 2 +2/3 = 0 which gives you a neutral neutron. Quarks are held together by the strong force.

Electrons form a "cloud" around the nucleus. It used to be thought that electrons orbited the nucleus in the same way that planets orbit the sun. However, the advent of quantum physics showed this not to be the case.

Electrons carry negative charge. It is the electromagnetic force that keeps electrons in their place.

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Physics, Astronomy & Cosmology / Re: Is a 3-wheeled car more stable if two of the wheels are at the front?

« on: 27/06/2008 00:53:20 »

A friend of mine had a Reliant Robin and I drove it a few times. It was a lot more stable than you would imagine. However, the Bond Bug was notorious for tipping over in corners. Both are 1 wheel at the front and 2 at the back.

The only 3-wheelers I can think of that had 2 front wheels were the Isetta Bubblecar and the Messerschmitt. I believe both had a rear engine.

Look at these 3-wheelers!

for instance...