Water Bottle Rockets

This semester in my STEM class I’ve been planning to do an engineering design project involving rockets with students. Our district STEM coordinator, Adam Zodrow, alerted me to the possibility of helping students create plastic “water bottle rockets” instead of Estes rocket engine powered cardboard models like they have in the past. The Instructables as well as ScienceToyMaker websites both have instructions about how to create water bottle rocket launchers out of PVC, but this weekend at the first EdCampTulsa conference in Jenks I found something which might be even better. Lisa Seay (@lisaseay), a middle school science teacher in Sand Springs, Oklahoma, shared about the PITSCO Aquaport II Water Rocket Launcher which she’s used for several years with great success. She has shared a 3 page PDF lesson plan for “Water Rocket Construction” on her outstanding website wiki. The PITSCO water rocket launcher costs about $225. I’m going to borrow Lisa’s and try it out with our after-school Maker’s club students in April, and then in May try the lesson with my 4th and 5th grade STEM students.

In doing research on water bottle rocket options, I also found the AquaPod launcher, shown in the photo below. It’s much cheaper (only $35) and has positive reviews on Amazon, but it does not have the safety valve of the PITSCO Aquaport. It also appears to be prone to launch malfunctions, as demonstrated in this UK YouTuber’s review from June 2013.

Have you tried water bottle rocket projects with students? If so, what do you recommend and what have your “lessons learned” been?

PITSCO sells a couple teacher lesson guides but I haven’t actually read either of these yet:

  1. Water Rockets Teacher’s Guide ($25)
  2. Bottle Rockets ($2.50)
This entry was posted in ideas.

One thought on “Water Bottle Rockets

  1. Our school has several PITSCO launchers. They’re eight or ten years old, and look slightly clunkier than the model you picture here, but it appears that the mechanism is about the same. The PITSCO launchers work reasonably well, although the aluminum clamps that hold the bottle in place tend to be fussy and are prone to bending, and misfires or early launches are a common occurrence if caution is not employed. Over time the other parts work loose. Both students and staff need to be trained to inspect the launcher carefully before use and between each launch to ensure safety.

    I’ve used the AquaPod as well. In fact, that’s one of my photos of the AquaPod you’ve used in your article! (I’m glad you found it useful.) That’s the first incarnation of the Aquapod, and I can’t fully recommend it. The main problem is that it is too light and it tips over when students pull the launch cord. I ended up using 35 pound scuba diving weight belts draped across the legs to hold the launcher in place, and even then, over-zealous students yanking on the cord can tip the launcher, firing the rocket horizontally rather than vertically. I believe later versions of the AquaPod have peg holes at the feet and pegs with which to anchor the launcher to the ground. This would be a significant improvement.

    Unfortunately, the AquaPod does, in fact, have an over-pressure safety valve built in to the launcher. I say “unfortunately” because as pump pressure approaches maximum, which I believe is only sixty pounds, the valve releases and all the air and water is expelled from the base of the device… onto the person doing the pumping. This obviously limits the maximum pressure, supposedly for safety. But hey, c’mon, you KNOW you’ll wanna pump those babies up to at least a hundred pounds of pressure, even if “sources” claim the bottles might burst.

    One more problem with the AquaPod is with the o-rings that seal the launch nozzle. They easily twist out of place and tear or break. It is essential to keep a supply — not just a few, a supply — of extra o-rings on hand for the AquaPod. For ease of operation, it helps, and in fact is almost essential, to lubricate the nozzle and o-ring with petroleum jelly (Vaseline) between every launch. Be sure to gently rotate the rocket when slipping it over the nozzle, and try not to pinch the o-ring.

    The AquaPod is cheap — I bought three of them out of pocket, along with a couple of good quality bicycle air pumps, because it was easier than hassling with checking out the PITSCO launcher from the school supply room and then discovering that the PITSCO was missing parts or otherwise not working. And the school air pumps were practically useless. If your school is anything like mine, with inane restrictions about purchasing supplies from “authorized vendors” using purchase orders, I’m sure you’re familiar with out of pocket expenses for science projects! 😉

    A word about the bike air pumps: I bought the Planet Bike STX pump through Amazon, about $35.00. Despite the negative reviews, I found the pumps were excellent for elementary school students. Second grade students who barely weigh 60 pounds themselves could pump the AquaPod up to fifty pounds or more easily. It’s simply a matter of knowing how to use the pump. Don’t lift the handle all the way, and flip the little lever at the end of the hose UP, not down like you used to in the old days, to secure the pump to the air valve.

    Another option: I looked at plans online for building a launcher out of PVC pipes. I ended up buying a pre-cut kit on eBay as it was less expensive than purchasing the materials at my local hardware store. I don’t recommend this approach. The home-built gizmos for securing and releasing the pressurized bottle from the launcher nozzle are fussy and unpredictable. Both the PITSCO and the AquaPod have better launch release mechanisms than you can build, or at least than you can build for a reasonable expense.

    One other option, if you (or your school) are made of money: a science teacher friend at a middle school in California uses an air compressor system to launch the rockets. The compressor pressurizes a metal tank. Valves on the tank are connected by hoses to a simple launcher tube set-up. A quick turn of the valve pressurizes the launcher and fires the rocket. It’s a sweet way to go if money is no object… and if you want to hassle with a pickup truck to haul a compressor out to the field.

    One advantage I can think of about the AquaPod is, of course, the price. You can buy six or eight of them for the cost of one PITSCO… and launching multiple rockets simultaneously is pretty cool! Dangerous… maybe… but so far my second and third graders (SPED, at that!) have all survived. They get a little (lot) wet, perhaps, but that’s part of the fun. With your Maker’s Club, perhaps a challenge for the students would be to devise ways to overcome the stability problems of the AquaPod launcher.

    I like the idea of a Maker’s Club. I might present that as an option to my principal next year.

    Good luck with your rockets!

Leave a Reply

Your email address will not be published. Required fields are marked *