I found this product on the shelf of our Science Prep room. I wanted a demo to introduce the topic of Nuclear Energy. I had beginner's luck by getting it to work the first time I tried it at home. But in front of a class it wouldn't work. It worked with both 91% Isopropyl and with 99% Methanol or Isopropyl.
I had to be patient in discovering the variables. The plastic dish needs to make good contact with the dry ice. I started with a flat large piece, but over time it got smaller than the dish and that led to warm spots at the bottom of the dish. You can also break the dry ice with a mallet into a powder and push the dish into the powder. Put a towel around it to make it last longer.
It also needs to be level. Otherwise the Alpha tracks drift off to one side. It is level when they don't drift much.
Finally, and most importantly: The light source and the angle between it and your eye position are critical. You may not see the tracks because your eye is not in the right place to see the reflections from the particle tracks. It helps to:
▫️Have others looking from different angles,
▫️Adjust the light source position,
Wait at least 15 minutes from when you start chilling the chamber (dish).
Your patience will be rewarded.
▫️Wiping the top of the chamber with Anti-Fog Cleaner will keep fogging due to the cold surface from blocking your view. Mine says it contains isopropyl alcohol so maybe just use that on a cloth!
Note Well: Our school has owned it longer than Lead 210's half life of 22.5 years and it still works well (see video).
WARNING: 