Dry ice can create fog when placed in water. This is an especially popular trick around Halloween to create a spooky atmosphere and is used often in theater as well. Here is how to do it yourself:
Add chunks of dry ice to water in a Styrofoam or other insulated container. The chemical reaction will create a fog effect. Using warm water will produce an even denser fog.
The fog will sink to the ground. You can use a fan on a low setting to move the 'smoke'.
The water will become carbonated, causing the fog to disappear. You will have to replace the carbonated water with fresh water in order to maintain the effect.
Room temperature does matter - you will get the most fog in a cool room.
It is very important to keep in mind that dry ice can be hazardous. Please read our safety precautions before you start experimenting.