Agree Learning Outcomes: Topic: P6.1.3 Nuclear Equations Spec link: P Time: 70 mins Recorded Assessment: Review: Half life graph drawn from results and half life calculated worksheet Present New Knowledge: What is half-life? How graphs can be interpreted Agree Learning Outcomes: Can describe what half-life is Can Interpret graphs of activity against time Can calculate the ratio of final to initial activity after several half lives. Apply To Demonstrate: Students to write their own description Students to produce their own graphs and calculate half life Construct Meaning: Demonstrate with paper and PHET simulation Half-life practical and results

In your book... What are the three forms of radioactive decay? What form of radioactive decay emits a Helium nucleus? What happens in Beta decay? What happens in Gamma decay? :

Radioactive Half-Life Key Words: Becquerel; half life; activity; radiation Key Words:

How do we measure the activity of radioactive material? Think back to the demonstration of Alpha, Beta and Gamma radiation - what did we use to measure the activity? Allow students time to reflect back on the use of the Geiger counter Explain that the Geiger counter is measuring the radiation emitted per second - this is the activity and is measured in Becquerels (Bq). 1 Bq = 1 count/second Key Words: Becquerel; half life; activity; radiation

What is half life? Watch the demo and try and write an explanation Take a piece of paper to explain half-life. Fold it into half and then half again and continue till you can do it no longer Explain that radioactive half-life works in a similar way, there is a length of time for the radioactivity of an isotope to reduce to halve, and this will be the same length of time for the radioactivity to go from a halve to a quarter and so on…. This simulation helps explain https://phet.colorado.edu/en/simulation/legacy/radioactive-dating-game Key Words: Becquerel; half life; activity; radiation

•Radioactive substances decay naturally Radioactive decay •Radioactive substances decay naturally •The half life of a radioisotope is the average time it takes for half of the nuclei present to decay – time for the activity to halve •Half-life will differ for different radioisotopes •It is a random process Key Words: Becquerel; half life; activity; radiation :

Radioactive Half-Life Key Words: Becquerel; half life; activity; radiation Key Words:

Half-life practical Write down how many dice you have Roll all the dice (from beaker onto desk) Remove all the ones that landed with the black side up Repeat steps 1-3 until you have no dice left (don’t forget to write down every time!) Draw a graph of ‘dice left’ (up the side) against ‘number of rolls’ (along the bottom) Can you find the ‘half life’? (how many rolls it takes for number of dice left to halve) This demonstrates the random nature of radioactive decay

Calculate your half-life... Look at the point where the activity has been reduced to half and then read the time value. Repeat this twice more to check your half-lives Key Words: Becquerel; half life; activity; radiation Key Words:

Radioactive Half-Life Key Words: Becquerel; half life; activity; radiation

Complete the worksheet

Contamination vs Irradiation (chromebooks) Spec point: recall the differences between contamination and irradiation effects and compare the hazards associated with these two Find out the difference between these two words How does this apply to the hazards of radioactivity? https://emergency.cdc.gov/radiation/pdf/infographic_contamination_versus_expos ure.pdf http://www.bbc.co.uk/schools/gcsebitesize/science/21c_pre_2011/energy/safehan dlingradmatrev3.shtml