Science Buddies: "Ask an Expert"

We found an experiment that we are going to try - but I can't find any info on why or how this works. You use a glass of water, 2 aa batteries, matches. You soak the batteries in the water for 30-40 min. then remove the batteries, you put the lit match over the glass and it is supposed to ignite. We have some ideas of why and how but we can't find the exact reason that this happens - Can anyone help???? Please.

Hi,
Welcome to the Ask an Expert forum.
I've never heard of this exact procedure, but what you are describing seems to be an experiment in water electrolysis:
http://en.wikipedia.org/wiki/Electrolysis_of_water
Please let us know if you have more questions about how that works.
Chris

ChrisG wrote:Hi,
Welcome to the Ask an Expert forum.
I've never heard of this exact procedure, but what you are describing seems to be an experiment in water electrolysis:
http://en.wikipedia.org/wiki/Electrolysis_of_water
Please let us know if you have more questions about how that works.
Chris

To expand on Chris's comments...

Electrolysis of water produces hydrogen and oxygen, both of which are (obviously!) flammable. Lighting these gases can be very dangerous, especially in combination (both gases togther).

I also haven't seen your method before, but alternate methods are in the videos (links below). It may not be a good science fair project (it seems more of a demonstration than experiment). If you do this project, please be VERY CAREFUL. Even without a lit match, these gases could catch fire from an electrical spark or such.

Here are two examples of this electrolysis. Both demonstrations are done at home. The videos give detailed instructions on how to make the device. The first link has better explanations of the science. The second link has some political statements about hydrogen cars and gasoline use at the end.
http://www.youtube.com/watch?v=5HWlx--tQbA
http://www.youtube.com/watch?v=zhm0ozrpHJ8

These last links shows how large quantities of oxygen and hydrogen can be very dangerous! Notice how far away the people stand from the reaction. I've seen this in person, and the videos don't really capture how loud and bright this explosion is.

http://www.youtube.com/watch?v=p3LUHAr12qI
http://www.youtube.com/watch?v=aGsf9Q_ShtY
http://www.youtube.com/watch?v=MMB2VR0087w

Have fun and be safe!

Louise

no it can't water can boil and turn into vapor but can not burn.