Half-Life Lab
Purpose: (Copy)
To simulate radioactive decay (half-life) and predict the hypothetical half-life of pennies
Hypotheses: (Copy)
What is the half-life of the head side of a coin?
What is the half-life of the tails side of a coin?
Materials: (Copy)
50 coins
1 container to shake coins in
Procedure: (Do not copy the procedure in your write-up.)
Steps:
Part 1:
1. Shake the coins in the container and gently dump them out on a flat surface.
2. Count the number of coins that ended up with the heads side facing up. Remove these coins
from the group and set them aside. Record this number under the column removed heads.
3. Gather the remaining coins (all should be with the tails side facing up) and place them back
in the container.
4. Repeat steps 1-3 until ALL coins have been removed from the sample.
Part 2:
5. Repeat steps 1-4 removing coins that have ended up with the tails side facing up and keep
coins that ended up heads side facing up.
Data: (you need an entire sheet of paper to record data)
YOU MAY NEED MORE THAN 8 ROWS. This is just showing the format of the table.
Data Table 1
Heads (part 1) Tails (part 1)
Throw # Removed
1.
2.
3.
4.
5.
6.
7.
8…
Remaining
Tails (part 2)
Heads (part 2)
Removed
Remaining
Questions:
1. How many rolls did it take for the number of coins to be reduced by at least half?
(These are your half-life readings.)
Heads (part 1):__________________
Tails (part 2):_________________
2. How many tosses of the coins did it take to remove all of the coins?
Heads (part 1):__________________
Tails (part 2):_________________
3. What was the half-life of the coins that you tossed in part 1?
4. What was the half-life of the coins that you tossed in part 2?
5. Why might your answers to questions 3 and 4 be different?
6. 1000 grams of substance X has a half-life of 10 yrs., how much will be left after10 yrs.?
7. 800 grams of substance X has a half-life of 10 yrs., how much will be left after 10 yrs.?
8. 1200 grams of substance Y has a half-life of 6 yrs., how much will be left after 6 yrs.?
9. 1500 grams of substance Z has a half-life of 8 yrs., how much will be left after 16 yrs.?
10. 2000 grams of substance X (half-life of 10 yrs.) how much will be left after…
a. 20 years?
b. 50 years?
c. 100 years?