Making Water in a Water Bottle

For this reaction, I used a 5 gallon water bottle like those found on office water coolers. The source of the reactants were compressed cylinders of industrial grade hydrogen and oxygen. In past years, the bottle was filled completely with hydrogen and then oxygen was added for a short period of time. I was trying my best to achieve a 2:1 ratio without going to great lengths to ensure it. Now I fill the bottle "over water" so that I can visually see what I am getting. The mouth of the bottle was covered with parafilm and kept upside down for its journey to the field behind the school. A standard rocket igniter was attached to one end of a 75 yard length of stereo wire. The bottle was propped at 45* angle using boards (or placed in a ring clamp) and the igniter was inserted in the mouth of the bottle. The wire was unrolled as we retreated behind a wooden structure some 40 yards away. With camera rolling, a 9V battery was touched to the free end of the wire. After a several second delay for electron travel, we made new water molecules in impressive fashion. This reaction is not for the faint of heart. It produces a sizeable shock/sound wave. For instance (#1), if you listen to the videotape, the sounds of car alarms can be heard shortly after the reaction. The parking lot is adjacent to the field about 150 yards from the reaction site. We had produced some gas molecules with tremendous amounts of kinetic energy. These molecules sped off and crashed into other molecules which started a chain collision process that eventually pushed on a car enough to set off the alarm system. For instance (#2), I was telling my classes about the experiment the next day. A student asked me for the exact time of the reaction. He was astonished by my answer. During swim practice that afternoon, the swim team was conducting practice in an indoor swim facility that is located in a park across from the reaction site. The pool is covered by a "bubble" during the colder months. The swimmers had been baffled by a sudden indoor rainshower that occurred on that afternoon. The fast moving molecules that went in the other direction had started a chain collision process that eventually pushed on the bubble enough to shake the condensation off its ceiling. A good teaching moment is to calculate how relatively few hydrogen molecules were present in the water bottle (compare to a Space Shuttle launch or the Hindenburg). If you want to see pictures, we have used a frame-by-frame VCR and a product called "Snappy" to take a few digital snapshots from the videotape. Follow me.... (29 K)