Detection by Diffusion Cloud Chamber Objective To create condensation trails which are evidence of the passage of alpha, beta and gamma radiations. Materials chamber with cover radiation source two blotting paper viewers strong light source (300 W to 500 W) dry ice alcohol Go to the online laboratory. Procedure 1.Soak the felt ring with alcohol. 2.Place the felt ring in the chamber and cover. 3.Put dry ice at the bottom of the chamber. 4.Insert the radioactive source through the hole in the side of the chamber. 5.Focus the strong light through the chamber. 6.Observe vapour trails against the black bottom of the chamber. Do you know? 1.Why are alpha particles easy to view with the chamber? 2.Why is dry ice needed? 3.Why is alcohol needed? *back* (C) 1999 ThinkQuest Team 27954