1. 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 x x Entrants 0 1 2 3 4 5 6 7 8 9 10 After Round 1024 512
256
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
The decay curve for radon-220.

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.1 2 3 4 5 6 7 8
Decayed
Not decayed
Activity of skittles (not decayed)
What does this show you about how elements decay?
It is random.
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 Isotope Half Life Strontium-90 29 Years Radon-222
3.8 Days
Yttrium-90
64 Hours
Thallium-210
80 seconds
Americium-242
141 Years
Lead-209
3.25 Hours
Carbon-14
5700 Years
Protactinium-233
27 Days
Oxygen-15
122 seconds
Curium-245
8500 Years
Plutonium-238
88 Years
Astatine-218
1.5 Seconds
Hydrogen-3
12 Years
Thorium-231
25.5 Hours
Polonium-210
138 Days

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.