I work with the young men in the Ta Khmau 2nd Branch, holding an activity day on Saturday afternoon, and teaching a class Sunday morning.
For some reason, which I now forget, I mentioned bottle rockets to President Samat, of the 2nd Branch which he jumped on immediately, strongly encouraging me to build a simple bottle rocket launcher.
The parts were available inexpensively so we soon had the launcher made, except for a minor problem. We could not find soda in small plastic bottles. Bottled water is everywhere but soda, which comes in a much stronger bottle was hard to find. We ultimately bought several 500 ml plastic bottles of Coca-cola, only to find the bottle mouth did not fit over the ½ inch (18mm) pipe. A long session with sandpaper and scraping with my pocket knife fixed that. (No one here seems to carry a pocket knife. They look at me funny when I pull mine out.)
President Samat and I went across the street to the church parking lot to test it out. He was like a little kid when he saw it work. I asked him to keep it a secret from the boys so we could surprise them on Saturday, to no avail. Then during my English class, Sister Tuck blabbed it out too. I have to admit, the launcher caused quite a stir when I brought it into the class because no one could figure out how it worked.
When the activity time came, I had four boys which were quickly joined by the guard and another adult. They were truly amazed when that first bottle rocketed into the air. After several dozen shots, the air valve I had obtained from a bicycle inner tube busted, ending their fun.
The repairs took a trip to a Moto and plastic pipe shop but we were soon rocketing again. Perhaps other launcher designs have more accurate aiming, but one of the bottles ended up on the church house roof, stuck in the gutter. After another dozen firings, the neck of the remaining bottle cracked, ending the flights, but the boys had had fun and had gotten wet. I believe we will see more pop bottles next week.