Brutal Water Cannon Defeats Summer Heat; Kills it on Documentation

There’s a war on, and while this over-the-top water blaster is certainly an escalation in the Water Wars arms race, that’s not the war we’re referring to. We’re talking about the Documentation War. Hackers, you’re on notice.

Gj3YAOLIf you want to see how a project should be documented, look no further than [Tim]’s forum posts over at From the insanely detailed BOM with catalog numbers and links to supplier websites, to scads of build photos with part number callouts, to the finely detailed build instructions, [Tim] has raised the stakes for anyone that documents any kind of build.

And that’s not even touching on the merits of the blaster itself, which has air and water tanks plumbed with every conceivable valve and fitting. There’s even an inline stream straightener made of bundled soda straws to keep the flow as laminar as possible. It looks like [Tim] and his colleagues are obsessed with launching streams of water as far as possible, and although bad weather has prevented an official measurement so far, from the video below it sure looks like he’s covering a huge distance with a stream that stays mostly intact to deliver the full blast to its intended target without losing a drop.

For as much fun as amped-up water guns appear to be, we haven’t seen too many grace these pages before. Going way back we covered a DIY super-soaker. For something much less involved than [Tim’s] masterpiece, you can pull together this pressurized water pistol in an afternoon.

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Second grade science project: a steam engine


If you’re looking for a way to let the kids get hand-ons with science this is a perfect example of how to do it. [Erich] wanted to help out with his 7-year-old’s science project. They decided to build a working model of a steam engine but couldn’t find online instructions appropriate for the age group. So the two of them not only pulled off the build, but then they wrote a guide for others to follow. The thing about it is, you really have to understand a concept to teach it to someone else. So we think the write-up is equally important to having actually done the experiment.

Steam can scald you if you’re not careful. But you don’t really need steam to explore the concepts of a steam engine. The main reason to use steam is that it’s a fairly rudimentary way to build pressure which can be converted to motion. For this demonstration the blue balloon provides that pressure. It’s feeding a reservoir that connects to the valve built out of straws. A plastic piston inside pushes against the crank shaft, spinning the cardboard wheel on the left. When the piston travels past the valve opening it releases the air pressure until the machine makes a revolution and is in place for the next push. This is well demonstrated in the clip after the break.

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