PHYS 0847 Lecture 4: Physics - Chapter 4
Document Summary
An atom consists of an electrons cloud which surrounds a tiny nucleus made of protons and neutrons. The electron cloud is about 1/10 nm; a human hair has a thickness of about 125,000 atoms. It is now possible to see individual atoms with a microscope. The nucleus is about 100,000 times smaller than the electron cloud. If the electron cloud were the size of a football stadium, the nucleus would be the size of a mosquito. But the nucleus contain 99. 9% of the mass. Proton and neutrons are made of other particles called quarks and gluons. As far as we know, electrons, quarks, and gluons cannot be broken down any further. String theory guesses that all particles are made of the sa(cid:373)e (cid:271)asi(cid:272) stuff (cid:272)alled (cid:862)st(cid:396)i(cid:374)gs(cid:863). The(cid:455) are called strings because they can vibrate in different ways to produce different particles.
