It's in the Clouds

A cloud chamber provides an effective way to observe the effects of nuclear radiation. It is particularly useful for studying the rate of alpha decay and the range of alpha particles. Inside the chamber, alcohol vapor is maintained in a supersaturated state using dry ice. When a harmless alpha-emitting radioactive source is introduced, the paths of the alpha particles become visible as condensation trails, allowing for direct observation of their behavior.

Objective   

To create condensation trails which are evidence of the passage of alpha particles.

Procedure

1. Soak the blotting paper with alcohol.

2. Place the blotting paper in the chamber and cover.

3. Place the chamber on dry ice.

4. Insert the radioactive source through the hole in the side of the chamber.

5. Focus the strong light through the chamber.

6. Observe vapor trails against the black bottom of the chamber.

7. Replace the radioactive source in test tube when experiment is complete.

Questions:

1. Why are alpha particles easy to view with the chamber?

2. Why is dry ice needed?

3. Why is alcohol needed?