Mushroom Cloud

dry ice mushroom cloud bubble

When dry ice is placed in warm water it sublimes very quickly forming a large amount of carbon dioxide gas. When a bubble is placed over this the bubble grows from the pressure.

Dry Ice in Universal Indicator

dry ice universal indicator acid base reaction

Universal indicator goes from red (pH 4) to violet (pH10) as the pH of a substance changes. Adding NaOH to water starts the solution off at pH 8-9 (blue). When dry ice is added to water it forms carbonic acid, and lowers the pH, which is the reason for the color changes. The “fog” that we see is condensed water vapor though, not carbon dioxide gas.

CO2 Bubbles

dry ice soap bubbles

CO2 gas from subliming dry ice gets caught in a soapy solution creating a column of bubbles. When the bubbles are popped, the “fog” that we see is condensed water vapor, not carbon dioxide gas.

Camphor Particles

camphor sublimation

In this demo, camphor particles are placed in water. They sublime at room temperature which is why camphor’s odor permeates the room so quickly. The gas that forms around the particles propels the particles in random directions. Earwax contains a large percentage of long chain fatty acids which form a monolayer in water, thus ceasing the motion of the camphor particles.