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What is an isotope?
An atom of the same element with the same number of protons but a different number of neutrons.
What might an unstable atom do?
It may undergo radioactive decay and/or change into another element.
What is special about radioactive decay?
Radioactive decay is a random process. We can not predict when an individual atom will decay.
What is ionisation?
The process of an atom becoming an ion (losing electrons).
Ways to detect ionising radiation
A Geiger-Muller Tube and counter or photographic film.
What is background radiation?
It is the day to day radiation caused by objects containing radioactive isotopes.
Examples of background radiation:
Living things, building materials (brick,concrete) and food.
What are alpha, beta and gamma particles?
How are alpha, beta and gamma particles created?
They are randomly emitted from unstable nuclei.
Charge of alpha, beta and gamma:
Range in air for alpha, beta and gamma:
What are alpha, beta and gamma particles blocked by?
Alpha, beta and gamma ionising ability:
Three safety methods when dealing with radiation sources:
Short time, large distance and tongs
Where does ionising radiation from space come from?
Our planet receives cosmic rays which are high energy particles from space.
Absorption / penetration of ionsing radiation experiment:
What is a half-life.
The half-life of an isotope is the time in which the activity of the source, counts recorded or number of radioactive atoms will halve.
Graph of a half-life
What is activity and what is it measured in?
Activity is the number of radioactive decays per second measured in Becquerels (Bq).
Half-life example
Alpha charge
Beta Charge
Gamma charge
Nuclear equation for radioactive decay example
Some radioactive isotopes…
decay to produce isotopes that are again reactive leading to chains forming.
Some radioactive materials…
stay radioactive for a very long time and emit a lot of radiation.
What is a use of radioactivity relating to cancer:
Cancer treatment - radiotherapy:
Gives a high dose of gamma rays to the tumour, aiming to kill it.
What is a use of radioactivity relating to manufacturing:
Thickness monitoring: e.g manufacturing aluminium foil:
Controls thickness of the foil.
Some betas will pass through and some will get blocked.
If the thickness changes, the amount that go through will change.
What is a use of radioactivity relating to sterilising:
The gamma rays kill bacteria.
E.g, syringe is perfectly clean.
What are some dangers of ionising radiation?
Cause mutations in living cells, can become cancerous.
Damage cells and tissue, can’t function properly.
Why does disposal of reactive waste need to be hidden?
Security guards and a safe location is needed so that no one tries to steal the waste and use it dangerously.
What is a use of radioactivity relating to movement?
Tracers:figuring out where something goes
Put some of the radioactive isotope into what you want tot trace and find out where it goes with the GM tube.
What is contamination?
This is when we get radioactive materials on ourselves, clothes, equipment or buildings.
This leads to irradiation.
What is irradiation?
This is when our bodies are blasted by ionising radiations.
