Activity 3

Radon in the air, captured with a balloon

Predict first, then observe, then explain. Lock in your predictions before the balloon goes near the detector.

Name Partner(s) Date

Predict, before you start

Two questions about the air and the balloon

Question 1. Does ordinary indoor air contain anything radioactive?

Yes, there is something radioactive in the air No, air is just nitrogen and oxygen I have no idea

Question 2. After the charged balloon is placed under the detector, the count over the next 100 minutes will...

Rise over time Stay about the same Fall over time

Write your reasoning for Question 2.

Predictions locked. You will find out at the bench.

Observe

Record your alpha counts

Count alpha particles only. For each 10-minute sample record the count in the second column. The activity in becquerels will calculate automatically.

Time (s)	Alpha particles counted	Activity (Bq)
0
600
1200
1800
2400
3000
3600
4200
4800
5400
6000

Sketch or describe the shape of your activity-vs-time graph.

Explain

What does it mean?

Did the count fall over time? What does a decreasing count tell you about what was stuck to the balloon? The half-life of the decay products you collected is roughly 50 minutes. Does your graph agree? Explain any differences.

Your predictions

Keep these in mind when the balloon goes near the detector.