Chemistry Blog

Flammable Bubbles: The old methane in soapy water demonstration

YouTube has a new video floating around featuring one of the coolest Chemistry demos, Flammable Bubbles.

This is one of my favorite experiments to perform. Actually, I’ve forced all my students in my synthetic labs to allow me to do this to them in order to pass my lab section. The actual setup for this experiments is quite straight forward. Add aquinox to a large beaker, add water until its 1/2 to 3/4 full. Get a hose and attach it to the natural gas spigot in the lab. Bubble gas through the soapy water until you have a lot of bubbles.Now before everyone goes and tries this, please follow the below safety tips. The video above violates every single safety consideration I could think of.
Safety

• Make sure appropriate eye protection is warn by everyone
• Make sure to do this experiment in a lab with a high ceiling or you might literally put the roof on fire.
• I’ve done this demo over a hundred times and it can sometimes burn a bit past your comfort level. One way to deal with this is to dip everybody’s hands in water before you apply the soapy bubbles to them. Wet hands will also have the added bonus of preventing bubbles from popping before you bring a flame near it.
• Turn off the gas line while having an open flame
• Make sure everyone has their hair pulled back
• If anyone has any wrist bands(See video above) make sure you have your students remove them
• Have your students extend their hands as far away from their body as possible.
• Some students get scared during this demo and as the flame develops will automatically try to retract their hands to their body. Make sure you tell them repeatedly and often to every single one of them that it is very important that they not move.

Have fun with the Flammable Bubbles demo just be more careful and safe than those in the video. Thanks Borek for bringing this video to my attention.

Mitch