An article by James Lochead MacMillan and the First Steps Waiuku children and teaching team
The children were showing interest in aliens and space. As good teachers we embraced this interest in space with books about aliens and learning about the solar system.
Teacher, James had a water bottle rocket launcher at home, which he brought in. Sadly this rocket only survived a few launches before the rubber seal broke and could not be replaced.
A week or two later James was reading Adam Buckingham's book, Turning Trash into Treasure. A few pages in, and there was an air rocket made from a wine cork and car valve. You pumped the bottle up until the pressure in the bottle was greater than the friction holding the cork in and in a reverse of a champagne cork the plastic bottle shoots off. James then thought about water being in-compressible, so if we fit a hose pipe to the wine cork, the water would flow in and compress the air inside the bottle until the friction failed and launched the bottle.
So then we created the "Rocket Blaster" as it was christened by two boys after it's first launch send the coke bottle about 40 meters into the sky.
At this stage the rocket blaster required 2 children to operate. Child 1, would fit the bottle onto the cork and then clear back to a pre-determined safe zone behind the boat. Child 2, would then get given the go-ahead to fire the rocket by the teacher. The bottles fired really fast between 2 seconds for small bottles all the way to about 8 seconds for big coke bottles.
A problem we had at this time was the tap taking about 10 times as long to be switched off, as it took to switch on, making a small muddy patch. Another problem was running out of coke bottles, as sometimes they flew over the fence.
Around a month later we added a ¼ turn ball valve at the launcher, allowing the water flow to be restricted at the tap and making the launch a single child operation. This worked awesomely and the launcher has remained unchanged since - don't mess with perfection!!
Over the following months we experimented with passengers in the form of a centre doll, T-rex and a stuffed Gorilla wearing a parachute.
This was awesome fun as the children (including a slightly large kid – the teacher) tried to find the best way to get the added weight of the stuffed toys airborne, sure we could have done it first time but the children would have learned James can do it... not they can do it.
James took a back seat mainly judging if their idea was safe and adjusting the safety zone. One of the children "M" came up with a cardboard sheet which the toy balanced on but was too thin and failed under the force of launch. "B" then asked if they could use a plastic seat, they struggled to balance the seat but managed to balance the seat in the end. James extended the safety zone by quite a lot for this launch just in case.
At the suggestion of another child we fitted a bottle rocket to a skate board with duct tape, The skate board flew across the playground really fast!.
Then several children retrieved different parts. A large coke bottle, reel of tape and a skate board (a bigger one) as per the skate board we had just made and a child's plastic seat top.
"M" then explained to James his idea, "M" was to sit on the seat also fitted to the skate board and fly across the playground really fast. We knew there wouldn't be enough force to do that as the weight would be multiplied by a large factor but "M" didn't. "M" helped build the rocket powered skate board. We test fired the skate board to check it still would fly and yes it did. "M" was desperate to be the test pilot. James did one more test first and added a bucket full of sand to the skate board just to be sure, it slowed the skateboard down quite a lot.
"M" then took up the position of test pilot and the look on his face as the bottle started to fill... then a loud pop and "M" shot forward about a metre.
He loved it - in his words: "Awesome Rocket Blaster Skate Board!"
Comments and questions are welcomed - please add these below
Another article by James you may also be interested in reading next is: Building a love of woodwork and creating a children's carpentry workshop