It's Halloween which means time for some spooky fun science! This will be my most explosive Halloween science segment yet! This segment is for demonstration of gases (and explosive Halloween science) and should not be tried at home.

Science lesson:

Demonstrating the interesting properties of a few gases.

Carbon dioxide gas: We can condense carbon dioxide into a sold and call it dry ice. Place this in water and it looks like it's boiling but it is not, it is subliming (solid to gas) at a temperature of -78.5 degrees Celsius (-109.5 degrees Fahrenheit! It makes for some very cool fog but it is not explosive.

Hydrogen gas: Is the lightest and most abundant of all gases in our universe. It is not reactive as long as you keep it away from a flame or spark. Once this gas meets a spark it will quickly combine with oxygen and produce water... and releases an incredible amount of energy in the process (and maybe a loud bang).

Acetylene gas: This is a gas that can easily be produced by adding water to a rock we make in the laboratory called calcium carbide. Calcium carbide was highly used before flashlights and bulbs as lights for a car or on a miner's cap. When acetylene is ignited it undergoes a combustion reaction producing a carbon dioxide and water... and explosive enough to carve my pumpkins.

For more science experiments from Kim, go to