Name____________________
HALF LIFE
Radioactive materials are characterized by their half –life.
Half Life is the time it takes for half of a material to decay into something else.
If a material has a half-life of one minute, after one minute ½ of the original molecules
are left, the others have decayed into something else. After another minute, ¼ of the
original molecules are left while the others have decayed into something else. After
another minute, 1/8 of the original molecules are left, while the others have decayed into
something else.
Purpose: To understand Half Life in radioactive decay
Equipment: Plastic container, 100 M&Ms, graph paper/laptop
Procedure:
1.
Count out a 100 M&Ms. Make sure each one has an M printed on only one side.
Place the 100 M&Ms in the container and shake it for several seconds. Open the
box and remove all of the ones that have the M face up. Count these and record
the number in Data Table A.
2.
Repeat Step 1 until one or no M&Ms remain.
3.
Add the number of M&Ms removed to find the original number of M&Ms.
For each shake, find the total number of M&Ms remaining.
4.
Plot the Number of M&Ms Remaining vs. Number of Shakes. Find the line that
best fits your data.
Analysis:
Study the graph. What approximate fraction of the remaining M&Ms were removed on
each shake?
Each shake represent a “half-life” for the M&Ms. What is meant by half life?
DATA TABLE A
Total number of pennies_________
Shake
Number
1
2
3
4
5
6
7
8
9
10
Number of M&Ms
Removed
Number of M&Ms
Remaining