radioactivity,nuclear equations, half life, contamination

carbon 14 14c6

some isotopes have an unstable nucleus, to become stable the nucleus gives out radiation this radiation is called radioactive decay

scientists cannot predict when a nucleus will decay

-the rate at which a source of unstable nuclei decay

becquerels- 1 bequerels is one decay per second

use a geiger muller counter

the count rate is the number of decays recorded each second by a detector

• alpha particle • gamma particle • beta particle

-helium alpha particles have 2 neutrons and 2 protons

a beta particle is an electron which is ejected from the nucleus at a very high speed the beta particle is formed inside a nucleus when a neutron changes to into a proton and a electron

gamma rays are not particles they are a type of electromagnetic radiation from the nucleus

sometimes given out by a nucleus

alpha particles are large they can travel around 5cm in air before they collide with air particles and stop

can travel further, can travel 15 cm in air before stopping

gamma radiation can travel several metres in air before stopping

relatively easy to stop can be stopped by a single sheet of paper

harder to stop can be stopped by a few millimeters of aluminium

gamma radiation is stopped by several centimeters of lead

when radiation collides with atoms, that causes an atom to lose electrons and form ions

alpha particles are very strongly ionising

quite strongly ionising but not as much as alpha particles

weakly ionising.