Every chemistry teacher should have a large stash of Calcium Carbide in the store room because it is the perfect chemical to make demonstrations that get people's attention! Needless to say, I buy it in bulk (find it here). Calcium carbide is a valuable tool to show several types of chemical reactions including single replacement, double replacement, combustion reactions and other chemistry principles.
Watch the video to learn how to make a calcium carbide cannon from PVC and check out the chemical reactions below to understand the chemistry of what is happening inside this loud, headache inducing cannon!
How to build a carbide cannon
(see instructions in YouTube video above)
How to do the carbide cannon demo
1 gram Calcium Carbide
20 ml water
ball or towel
ramrod (meter stick)
Procedure for lighting the carbide cannon
Unscrew the cap from the end of the PVC cannon. Place 1 gram of carbide in the cap and screw on tightly. Set cannon in stand (see video). While holding the barrel upright, pour 20 ml of water down the barrel making sure the water goes directly to the bottom where the carbide is being stored. Place the ball in the ball (or towel) in the opening of the barrel and push down about half the length of the barrel with the ramrod (meter stick or stick). Point the barrel away from anything that could be harmed.
The longer you wait, the more acetylene and the bigger the bang in the cannon. When ready (I usually wait about 20 seconds), light the lighter and hold it near the ignition hole. Remove the duct tape covering the hole and move the lighter near the hole. Then, BOOM!
I visited Montana This Morning on KTVQ (CBS) to share the wonders of science and show the viewers of Montana and Wyoming just how awesome calcium carbide can be!
Calcium Carbide and water reaction equation:
calcium carbide + water --> acetylene + calcium hydroxide
CaC2 + H2O --> C2H2 + Ca(OH)2
Calcium Carbide and water reaction balanced chemical equation:
CaC2 + 2 H2O --> C2H2 + Ca(OH)2
Acetylene combustion reaction equation:
acetylene gas + oxygen --> carbon dioxide + water
C2H2 + O2 --> CO2 + H2O
Acetylene combustion balanced chemical equation:
2 C2H2 + 5 O2 --> 4 CO2 + 2 H2O
As always, use caution when performing science experiments. Calcium carbide and acetylene gas can be very dangerous if not handled properly. Also, the these cannons can shoot projectiles more than 200 yards (180 meters) and could cause physical harm and/or property damage.
I've got another video explaining how to light a calcium carbide miner's lamp. Click here to learn all about how carbide allowed miners to make light in the darkness of the coal shafts.