4M Water Rocket Kit, DIY Science Space Stem Toys, For Boys & Girls Ages 8+

The rocket is a fun activity for sure. The assembly was very easy and the operation is very simple. I don’t have a hand pump so I used a batter operated one and it works really fast! It would be great for a science project, learning about the pressures, water levels, and bottle sizes. How they correspond to height of the bottle on launch. It’s a good transition into model rockets too.Recommend for sure, but if you are really going to use differing equipment, it might be a good idea to get a longer tube for the air. You can pick them up from any hardware store. Electric pump with digital pressure or preset limit would be best for more precise experiments.

This is a pretty great kit, especially for the price. It was pretty easy to build, in fact I was able to let my daughters do most of the steps, and we had it together very quickly. The fins are pretty heavy-duty and haven't broken yet, even after many flights and landings; I've been careful to make sure that the fin assembly gets screwed on by the center fitting, though, rather than using the fins themselves as levers - I think that might break them. An extra fin was included. I was disappointed at first that there's no specific release mechanism - you just wedge the plug up into the mouth of the bottle, and pump until it lets go. However, this turns out to be part of the fun of the process, as you never know quite when it will take off; it also lets you change up how high it goes (and how hard it is to pump up) by how hard you jam in the plug. (That is, for my younger daughter, I could put it in relatively gently - or let her put it in - and it would let go at a lower pressure, which was within her ability to pump it up.) It can go quite high, probably 100 feet on a good shot - we have done most of our shooting from the middle of a golf fairway in order to have enough space. Now, if you're handy, you could build this from parts in a hardware store and an hour or two at your workbench - but the fitting on the plug is actually pretty clever in its design (so that the pressure tends to make the hose more secure rather than blowing it off), and the fin assembly is hardy but easy to disassemble and reassemble. All in all it's great fun and a worthwhile buy.

My son wanted a "rocket set" for his 5th birthday, but couldn't really explain what he meant, so research led me to this. I've got a few cautions about it and I'll get to those, but there's plenty of great stuff about this toy.1) We can consistently launch this rocket about 4 stories high. It makes a great rocket sound and takes off like, well, a rocket. It's a blast, a huge performer. You know how you worry that things won't be as cool in practice as advertized? This is way cooler! Very exciting every time.2) Scientific method. We've been forming hypothesizes about whether more or less water would make it go higher and then discussing how to measure and what environmental factors (wind) might impact the results. Got the brain working while we're having fun.3) I can't imagine a toy being better at helping to make new friends. Every time we launch it up at our play ground, all of the kids and some of the parents get involved, ask questions, want to have a turn. We form launch teams, recovery teams, fueling teams, etc. Our boy has met some kids this way who are in his Kindergarten class that starts this week. He'll start school with a few friends in his class because of this toy. Can't really ask for more than that in a toy!Now a few tweaks and warnings:I am a road cyclist. Road bikes have smaller valve stems than regular bikes and things like wheelbarrows and cars. So, I happen to have pumps for both standards, but assumed that this was designed for the standard bike pump valve. The valve that comes with the rocket is too small to get a seal with the standard pump, but we get a better one with my road bike pump (Presta valve). The rocket launches by building up pressure from the pump and the water, so this is pretty important.With the presta pump, some air still leaks out. I have one kid hold the joint when we launch, but we still loose a little air that way. It's working for us, but this could be better implemented. I may work to modify ours at some point. I'm sure even with a standard pump, you could get this to work, but it might take some tweaking.All in all and amazing fun, safe and sneakly educational toy that has brought kids together and formed new friendships...all for $20. Can't beat it.

The kids love it. Having fun trying different bottles beside the one included. Just guessing I believe they have launched it 60 ft high or more so far. I think it will last longer than their attention spans, or their dinky bicycle pump.