Pre-Lab 13 Assignment: Radioactive Decay

Radioactive Decay v 0.1
Question 1.4 Compare the value you obtained in Question (1.3) with the accepted value of the
half-life of 14 6C of 5730yr. Do they agree?
Now that you know how to determine the half-life, the mean life, and the decay constant of a
given isotope by looking at the activity of the radioactive sample as a function of time you are
ready to determine the half-life of an unknown isotope by measuring its activity over a period
of time.
Investigation 2:
Determining the Half-Life of a Radioactive Sample
In this section we will determine the half-life, the mean life and the decay constant of a radioactive
sample of an unknown isotope.
For the activities in this investigation you will need:
• computer-based laboratory system
• experiment configuration files
• radioactivity probe
• small beaker
• radioactive sample (handled by the lab technician)
Precaution The level of radioactivity in the samples is very low, and will not cause any harm,
provided they are not ingested or allowed to come into contact with the skin. However, care
should always be exercised when handling any radioactive substance. If a spill should occur, it
should be wiped up immediately and the paper towels discarded in a container provided. DO
NOT EAT OR DRINK while handling radioactive material.
Activity 2.1: Measuring the Activity of the Sample
Step 1: Open the Lab file Lab13 A 1
Step 2: Connect the radioactivity probe to the socket named Dig.1 in the Vernier adapter.
Step 3: Place the measuring window of the probe directly in front of the clean beaker.
Step 4: When you are ready to start your experiment request that the lab technician put the
sample in your beaker.
Step 5: Immediately after your sample is poured in the beaker click the collect button in the
Logger Pro software. Be patient as the total collection time is 20 minutes. Once the
collect button appears again, you are ready to analyze your results. The probe will be
collecting raw counts of the activity of the sample. These are the number of decays over
a period of 5 seconds.
PHYS-204:Physics II Laboratory 5