Sponsored by Hawai`i Space Grant Consortium, Hawai`i Institute of Geophysics and Planetology, University of Hawaii, 2001

HYDROGEN BALLOON
Created by Dale Olive and Randy Scoville
Future Flight Hawai`i instructors

Demonstration at a glance:
Hydrogen gas is generated and trapped in a water balloon. When lit, the hydrogen balloon explodes with a loud bang.

Set-up:
To generate enough hydrogen gas I use hydrochloric acid poured over zinc metal in a flask. It is generated by the following reaction:

2HCl (aq) + Zn (s) > ZnCl2 (aq) + H2 (g)

Using a plastic thistle tube inserted into a one-hole stopper I catch the hydrogen gas in an empty water balloon affixed to the top of the tube. When full, I tie off the balloon and demonstrate that hydrogen is lighter than air. After affixing the balloon to the table, I light it from a distance by taping a match to a meter stick.

Theory:
This is a good demo to show the energy potential of hydrogen gas. The reaction goes as follows:

2H2 (g) + O2 (g) > 2H2O (g)

When the balloon is lit, hydrogen in the balloon mixes with oxygen in the air at a two to one ration creating water and releasing a lot of energy.

Extension:
A good extension discussion could center on the Hindenburg which was filled with hydrogen gas when it exploded into flames. Although this incident is foremost in people's minds when we mention hydrogen, it still is a promising fuel source. Notice the only product is water! It truly is a clean burning fuel. I've seen hydrogen-burning cars but at $4 a gallon for liquid hydrogen we may not see it in mass production soon. Although at today's gas prices, we just may???

Index of Activities.
http://www.soest.hawaii.edu/spacegrant/ScienceDemos/
Communications: Hawaii Space Grant Office
This activity is featured in Future Flight Hawaii, a K-12 Education Project of Hawaii Space Grant Consortium.
FEB 27 2001.