1. These particles make up
Radioactivity
This was discovered by Becquerel in the 1890’s.
A radioactive element is not stable.
Unstable elements will decay over time.
When an element decays, particles in the nucleus escape into their surroundings.
These particles make up
nuclear radiation

2. Radioactivity There are different radioactive particles.
Each particle has it’s own charge.
Each particle has different penetration powers.
Beta (β), charge of -1, stopped by thin metal.
Gamma (γ), charge of 0, stopped by concrete.
Alpha (α), Charge of +2, stopped by cardboard.
Alpha (α)
Beta (β)
Gamma (Y)

3. Radioactivity
If radioactive particles are allowed to pass through charged plates, some particles will be deflected.
Alpha particles go
towards the
negative plate
Gamma particles are
not deflected
either way
Beta particles go
toward the
positive plate