5-RAD-02

Outcomes

• Pupils can define and understand the term 'activity' and state its unit - becquerel(Bq)
• Pupils define 'half-life'
• Pupils can use graphs to determine half-life

Specification References

• 7.10 understand that the activity of a radioactive source decreases over a period of time and is measured in becquerels
• 7.11 recall the term 'half-life' and understand that it is different for different radioactive isotopes
• 7.12 use the concept of half-life to carry out simple calculations on activity

Starter

Tell pupils that they'll be playing a game today. Show them the pots with dice and start a short discussion about how gambling, winning the lottery is all relative and RANDOM.

Main Body of Lesson

• explain to the pupils that you'll be considering the dice being radioactive atoms and that the radioactive unstable atoms disintegrate in a unpredictible way. This is what you are going to prove today.
• if you shake and throw all the dice-atoms, some will land with the marked face upwards. remove these disintegrated 'atoms' and count how many atoms survived. repeat the process with the surviving dice and continue until all of them have 'decayed'.
• plot a graph of the number of dice-atoms surviving against number of throws
• the graph shows a decay curve for a radioactive substance
• define half-life as time taken for half of the atoms to decay
• teach pupils how to find the half-life of their graph

Plenary

• different substances, different isotopes have different half-life values
• the radioactive decay is a random process

Additional Information

Resources Required

• dice

Safety/Hazards

• None