Hello Mr. Krampf. I would really love to try this but I don't know to get my hands on dry ice. I live in Latvia and I have never even heard another person besides me mention frozen co2. Is it hard to find or is there some special shop that can sell it to you? Is dry ice really necessary or could I use regular ice?

Thank you!

We could not see any cloud vapor even in a dark room with the LED light. First we used a larger plastic container than yours (from a sheet cake), and then we tried a smaller one (a tall cylindrical hard plastic CD package). We did not paint our cookie sheet black. On our second try, with the smaller container, we used a darker cake pan. We thought maybe too much of the alcohol evaporated from the paper towel while we were getting the plumbers putty ready; we started over with a lot more alcohol but still no cloud. Our block of dry ice was definitely getting everything cold, and we think we had the containers sealed well. Any ideas about where we went wrong? Also, two notes: 1) We read that the Coleman brand lantern mantels do not use the radioactive substance any more, but the ones that are made in India still do (so we ordered a package that noted it was made in India). 2) We read that a tiny percentage of the potassium atoms in “salt substitute” (potassium chloride) are radioactive and the radiation can easily be detected with a Geiger counter. Therefore, we also put some of this salt in our cloud chamber to determine if we could see evidence of it emitting particles. Since we never got a cloud to form we could not tell. Have you tried it? Thank you so much for site. We love the experiments, especially the ones involving chocolate!

i'm reading this book and an angry mean cloud is following the main character a round!!

great experiment and video up to the point where Robert says, "...background radiation..." and then both the flash and quicktime videos stop loading ---
hmmm ???