# Half life

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## Half life

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1. Half life What is the half life of an element and why is this important? Starter: 1024 competitors enter a tournament. Each round half of them are eliminated. Sketch points on a graph to show how many competitors are left after each round.

2. Starter . x 1024 x Entrants 512 x 256 0 1 2 3 4 5 6 7 8 9 10 After Round

3. Radioactivity Look at the graph. 1) describe what the half life is. What is the half life of this chemical?

4. Radioactive Half-life • Radioactive half-life is the average time taken for the activity of a sample to halve.

5. What is the half life of radon-220? Could be a %age

6. Half life Graph 2 • Take a chocolate finger. • Use the chocolate finger to point on your graph. • Measure and eat exactly 1 half of the chocolate finger. • Move the finger along 1 big square and use the top of the finger to draw the next point. • Half again and repeat

7. Length of Chocolate Finger Time (AU)

8. The Half Life Game • Throw 50 skittles into a tray. • Remove those with the S facing upwards. • Record how many you are left with. • Repeat until you have done this 10 times OR have none left. • Draw a graph and work out the half life.

9. Record your data, use it to plot a graph. Activity of skittles (not decayed) What does this show you about how elements decay? Time (AU)

10. Half Life of Elements • Work out which element you have been given using the Half Life Challenge. • Done? What sort of decay is it? • Write an equation. • Too easy? • Do 1 more and compare the 2 elements. How similar are they?

11. Half Life Challenge

12. How is this useful • Medical -

13. Task – ppt 2 • use the graph provided to work out the age of the objects that were found in an archaeological dig.