Learning about rockets

SINEAD SENEK

Let’s see what we know and what we don’t know. First question, question 1: What type of force is friction? What type of force is friction? Is it (a) how we swim, (b) how things fall through the air, (c) a contact force or (d) speeding up and slowing down? So look at all your options, choose one – (a), (b), (c) or (d) – and record it in your book. Away you go.

SINEAD SENEK

I had a whole lot of questions about forces and gravity and so on, and then they just made a choice – (a), (b), will we log it in? – and we logged it in and so forth, and that gave me a really good feel for what they knew and understood. It used a lot of technical terms, and it gave me a good idea of what they did know and what they didn’t know. And that really pointed out that there were some that didn’t know about gravity in the class. They knew a little bit about friction. They didn’t really understand the concept around forces as such, and they didn’t really know any history about rockets.

SINEAD SENEK

Make your choice and record it down. Grace?

STUDENT

(d) equal.

SINEAD SENEK

Well done. You’ve earned yourself $500.

SINEAD SENEK

They all knew Albert Einstein, and they sort of talked about his hairstyle, which wasn’t really the scientific angle we were looking for, but it gave me a really good idea of where I needed to start with them.

STUDENT

Soon the British were always using rockets.

SINEAD SENEK

We took that history side of it, which they found quite interesting, that it started with the fireworks and then went from there to the military use and cannons and so forth, right up to Robert Goddard with the liquid fuel rocket, and then that’s when they started looking at rockets for something other than military purposes to actually explore space. And then we talked a little bit about why do we have to put so much fuel to get this thing off the ground, because what’s happening here? And that led us on to a discussion about gravity.

And then we did some little fun experiments about pushing and pulling things around the classroom.

SINEAD SENEK

So we’re going to think about what’s actually happening, thinking about what we’ve learnt so far about forces, thinking about our discussions that we’ve already had around that and what’s actually happening at that time.

SINEAD SENEK

There’s the skateboard one. That’s again on the Science Hub site where they just push each other on skateboards.

SINEAD SENEK

And what do you think was happening there for Dara as he pushed Kate?

STUDENT

He’s bouncing off Kate. There’s an opposite reaction going on.

SINEAD SENEK

Really good thinking there, kids.

SINEAD SENEK

And then we did the balloon experiment. You had some people holding the string. You had another person releasing the balloon. You had the other person timing it and then a person recording it. And then we timed it, the balloon coming down the string, and then we angled it up to a right angle, and then they had to look at their data – which one worked better? Why do you think it worked better? Why do you think it was faster that way and not the other way and so on? Once again, the maths came into it, because they had to angle their balloon on their string at different angles, so they all got to know what a right angle was and 90°, and then from that, we went on to view some of the video material on the Science Hub site, looking at the actual idea of rockets. And then the Rocket Lab guy – we viewed him a couple of times.

VIDEO CLIP – PETER BECK, ROCKET LAB

One of the important things to explain about the design of a rocket and the whole efficiency equation, if you will, is for every gram of inert mass – when I say inert mass, it means like propellant tank, fins, you know – the ratio is around about 10 grams of fuel.

SINEAD SENEK

In one video clip, which was really important for us before we launched our rockets, he talked about each time you add – you’re going to add into your rocket to get it off the ground – so he said if you add some more screws, well, that adds some more weight, so you’ve got to add some more propellant, but then you’ve got to make your tank bigger, and that’s adding more weight.

He talked about the cycle of doom, which the kids really quite hooked into, and about how they try and solve that problem. And that was a really good opportunity, after that video, to talk about, look, there are often problems in engineering and science and even just in the constructing of something that you come across. There’s so much problem solving you’re having to do, and that’s an important part of your collaborative work.

STUDENT

Three fins – around 21 centimetres.

SINEAD SENEK

So then it sort of led into, OK, if we’re making rockets, why are we putting fins on? And why are we putting the nose – the golf ball – on it? Then we got into discussions about weight, mass, drag, you know, air resistance, and that’s when we really get into the rocket science aspect of it. We talked about the shape of the fin, and why it’s designed that way. We talked about not making them too long along our bottle because that creates more drag, but we needed them there for stability – for our rocket to be stable.

At the end of it, they were just thrilled. They had these rockets. And then it was just finding the perfect day to launch them, and the space to launch them. They chose how much water they wanted to put in their rockets and record that down as well. And then I wasn’t too sure how many pumps of air I should put in, so it was a bit experimental.

So when we got to the astroturf, I angled it and I thought, I’m pretty safe here. We’ve got a big fence, we’ve got trees. If anything’s going to go that high, that will stop it. I had two girls that gave me their bottle, and they’d done a really great job of it, and I pumped it, pumped it, and then I thought, oh, put a bit more air in, and I pumped it. And when we launched it, it just flew. It flew over the fence, over the treetops, into the neighbour’s backyard. And I was sort of standing there … and the kids thought it was fantastic.

I was more worried in case it landed through somebody’s window. We did get it back. Some boys went over and got it back. I said to the kids, OK, that’s trial and error for Mrs Senek. And they said, I think you might have to do less pumps. So we reduced the pumps, so it stayed within the designated area, but it was amazing how they flew.

SINEAD SENEK

It’s really flowed neatly, because my writing time and focus now is all about our topic. I said to the kids you can choose to write about forces, you can choose about rockets or to write about both.

We’ve all got the same knowledge. When we do our rubrics and when we do our self-assessment and peer assessment, the kids can give each other really good feedback because, well, I know about this topic as well, so I can tell you what’s missing. It’s a good collaborative writing focus, because we’re not just writing different explanations about anything we’re interested in – we’re all writing about our topic, we’ve all built up our knowledge about our topic, we’ve all got the support material there to write and go back to.

So it’s been a really nice easy flowover into the writing focus, and they’ve actually written more because they know about their topic.

Acknowledgements
Sinead Senek
Sts Peter and Paul School