1. I Have The Power We are learning to….
describe the penetrative power of alpha, beta and gamma radiation and use the properties of each to explain their ionising power.
Am   +
237 Np 93
Cs   +
137 Ba 56 60
Ni   + 26 60 Ni 26

2. I Have The Power ALPHA BETA GAMMA So why is radiation so dangerous?
Watch the demonstration and decide for yourself.
YES – DRAW OUT THE TABLE
Radiation
Type
Initial Count Rate
(1 min)
Paper
Thin Aluminium
Lead
BACKGROUND
ALPHA
BETA
GAMMA
Put the radiation types in order from least penetrating to most penetrating

4. Ionisation I Have The Power INTERLUDE
When Alpha or Beta particles pass another atom, they tend to pull electrons off it.
We then say that the atom is ionised
α – particles have 2 protons – so they have a +2 charge
β – particles are electrons – so they have a -1 charge
γ radiation is just energy – so it has no charge

5. I Have The Power
α – particles have 2 protons – so they have a +2 charge
This means they ionise other atoms very easily by stealing their electrons.
This means they are heavy.
This means they lose their energy very quickly in air – which is why they have little penetrative power – even the layers of dead skin on us are enough to stop alpha particles.
This means they very dangers if inhales or ingested because they easily damage our cells by ionising them!

6. I Have The Power
β – particles are electrons – so they have a -1 charge
This means they don’t ionise other atoms very easily.
This means they are light.
This means they are able to interact with skin cells causing burns – but like alpha radiation are more dangerous when ingested or inhaled.
This means they lose their energy more slowly than alpha particles – which is why they have a greater penetrative power – but are able to be stopped by thin layers of metal

7. γ radiation is just energy – so it has no charge
I Have The Power
γ radiation is just energy – so it has no charge
This means they are very penetrating
There are high energy and high frequency and travel at the speed of light.
This makes them very penetrating, and they will pass right through paper or aluminium. It takes several centimetres of lead to noticeably reduce their strength, and still some get through! This makes them extremely dangerous as they can pass right through us, transferring their energy to our cells which can cause alterations to DNA, mutations and of course cancer.

8. Thin aluminium sheets, very think clothing
I Have The Power
Fill in the table below based on what you have learnt in today’s lesson
Radiation Type
Charge
Penetrative Power
Stopped by
Ionisation Power
ALPHA RADIATION +2
Short
Thin paper, skin
Strong
BETA RADIATION -1
Mid Range
Thin aluminium sheets, very think clothing
Medium
GAMMA RADIATION
Long
Thick lead
Weak

9. I Have The Power We have learnt to.....
Order alpha, beta and gamma radiation in terms of their penetrative power.
Define ionisation.
Explain the different ionising capabilities of each type of radiation.