1. Types of Radioactivity
Different ways to help you
& kill you

2. Discovering Radioactivity
In the diagram a “beam” of radioactivity is being emitted from a substance and passed through charged plates.
The results show that beam is actually made up of 3 different types of radioactivity (1-3).
Using the results on the photographic plate, determine the charge of each of the 3 types of radioactivity that hit the plate.
Also determine the relative mass of beam 1 & 3.

3. Rutherford’s Experiment
The #1 is attracted to the + plate, so is negatively charged.
The #2 is not attracted to either plate so is neutral.
The #3 is attracted to the – plate so is positively charged.
Beam 1 is has a larger deflection than 3 so the particle that makes up beam 1 is smaller than that of beam 3.

4. a particle
Is a positively charged particle emitted from the nucleus, made of 2 protons & 2 neutrons.
Has very little penetrating ability. Stopped by paper & skin.
Does the most damage once it enters the body.

5. b particles
Consists of a high speed electron that is ejected from the nucleus as a neutron decays.
Has some penetrating ability. Can pass thru paper. Can penetrate a few mm into the skin. Is stopped by heavy clothing.
Does a medium amount of damage once it enters the body.

6. g ray
Is NOT a particle, but a type of electromagnetic radiation (wave energy – like light).
Has a very high penetrating ability. Passes thru your body. Stopped by thick lead or concrete.
Does the least amount of damage as it passes through the body.

7. Effects once in the body