Atom (Physics)

Radiation is energy traveling in the form of particles or waves in bundles of energy called photons. Some everyday examples are microwaves used to cook food, radio waves for radio and television, light, and x-rays used in medicine.

 

Radiation is energy that travels and spreads out as it goes – the visible light that comes from a lamp in your house and the radio waves that come from a radio station are two types of electromagnetic radiation. The other types of EM radiation that make up the electromagnetic spectrum are microwaves, infrared light, ultraviolet light, X-rays and gamma-rays.  

Radioactivity is a natural and spontaneous process by which the unstable atoms of an element emit or radiate excess energy in the form of particles or waves. These emissions are collectively called ionizing radiations. Depending on how the nucleus loses this excess energy either a lower energy atom of the same form will result, or a completely different nucleus and atom can be formed.

Ionization is a particular characteristic of the radiation produced when radioactive elements decay. These radiations are of such high energy that when they interact with materials, they can remove electrons from the atoms in the material. This effect is the reason why ionizing radiation is hazardous to health, and provides the means by which radiation can be detected.


ATOM

In the early 1900's many scientists had turned their attention to investigating the structure of the atom.  Many models were proposed  and a handful have been adopted as ways to describe the atom.  Neither of them are perfect but they have brought us a long way toward understanding these building blocks.   Three of particular interest to us in physics are:

1. The Rutherford Model
2. The Bohr Model
3. The Cloud Model

 Even though these models are different, neither one excludes the other two.  Accepting one model does not cancel out the other two.  It is possible to accept all three models at the same time.

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