What is ionization?
Radiation from radioactive substances can knock electrons out of atoms
Atoms become positively charged when losing electrons
How can ionisation in living cell?
Damage/kill the cell
How does an object become irradiated?
If it is exposed to ionizing radiation
Remember that the object does not become radioactive
What is radioactive contamination?
Is unwanted presence of materials containing radioactive atoms on other materials
How are alpha particles strongly ionising?
Consist of two protons and two neutrons
Relatively large , alpha particles have lots of collisions with atoms
What can alpha particles be stopped by?
With collisions, alpha particles do not penetrate far into thin sheet or paper, human skin or few centimetres of air
What movement of the beta particle?
Fast-moving electrons emitted from the nucleus
How are beta particles less ionizing?
Much smaller and faster than alpha particles
less ionising and penetrate further into material than alpha particles
What are beta particles blocked by?
Thin sheet of aluminium or few metres of air
How are gamma radiation weakly ionising and very penetrating?
They are electromagnetic waves so they travel a long way through material before colliding with atom
What can stop gamma radiation?
Several centimetres of lead/concrete needed to be absorbed
ultimate range in the air