# What’s wrong with my cloud chamber setup?

For my setup, I am using a fish tank, lined with black felt and with one side open for viewing and a slit on a side for the light. I have a pretty bright multi led flashlight. I am using dry ice blocks inside a stryofoam container that is separated from the chamber by a metal cooking sheet. I am using 91% IPA, and taped the bottom of the fish tank to the tray to seal it. I am using some hand warmers to heat the top of the tank.

All that happens (after 4 attempts) is that the IPA begins condensing onto the sheet. I never see mist. I have tried to reposition the light, and have used other lights. It is dark in the room.

• Is IPA the alcohol of this demonstration? youtube.com/watch?v=xky3f1aSkB8 . Ale does not have enough alcohol – anna v Sep 13 '18 at 4:39
• Is IPA isopropyl alcohol? – PM 2Ring Sep 13 '18 at 11:03
• IPA = India Pale Ale in my vocabulary :) – mike stone Sep 13 '18 at 18:07

The sensitive layer in such a cloud chamber is very thin $(\sim \rm mm)$, near the bottom of the chamber $(\sim \rm cm)$ and dynamic in that the alcohol vapour from the top is cooling as it drops and the air becomes supersaturated with alcohol vapour in that sensitive layer.