This activity is tried and true and students enjoy seeing the ash creation and the cloud that appears out of the container. If a metal tray is not available, students can also make a tray from aluminum foil by folding it 3 or 4 times so that is stiff enough to hold ice. Students trying this at home, will need a parent to help them create the ash for their cloud. I’ve also taught this activity without ice in a classroom using a clear soda bottle. Using a 20oz clear plastic soda bottle with a lid, warm water, and matches; like the activity on this site, a diffused match (ash) is placed in the bottle of warm water. Secure the lid back on the bottle and squeeze the sides of the bottle to simulate high pressure (a hot day with clear skies) then release the bottle for low pressure (overcast or cloudy day) where clouds will form in the bottle. There are clear explanations and some great examples of condensation on this site. Cloud in a bottle is a good demonstration for the water cycle as well.