The science topic “Forces” cries out for a practical approach. You can do it the Qualifications and Curriculum Authority way, looking at moving traffic (key stage 1) and working with elastic bands and weights (KS2), or you can go out on the field and fire a rocket 200 metres into the air and watch it come down on a parachute.
Bob Jelley, head of St Giles Junior School in Warwickshire, thinks it’s no contest.
“The QCA provides good purposeful experimental stuff, but if you want to do something spectacular you can’t beat a rocket.”
He uses a commercial plastic model about half a metre long. It’s powered by a replaceable one-shot “engine” - a small block of solid fuel inserted into the rear and fired electrically by a battery powered filament.
Each launch is filled with drama. The rocket is settled on its launching pad, everyone stands back, and wires are unrolled to a remote switch.
There’s the countdown, the closing of the switch, a pause and the rocket whooshes skywards.
It climbs, accelerated by the thrust of the engine, working against gravity and aerodynamic drag. The engine stops and it continues to coast upwards, the speed diminishing as gravity and drag take over. When it reaches the peak of its trajectory and starts to fall a parachute is deployed (an important safety requirement), harnessing the drag of the air to offset the force of gravity. The rocket then drifts to earth. The process exemplifies the principles and vocabulary of forces - thrust from the engine, gravity, drag - and each of Newton’s laws of motion is seen in action.
How to extract the learning from the experience?
“You could do some work on forces beforehand,” says Bob Jelley, “or you can just go out and do it and then have a discussion to build up the story of what happened, using ICT or OHP or whiteboard, asking children to draw what they think happens, and suggest words to describe each phase of the flight.”
Forces, he points out, is in the science curriculum from KS1 to secondary.
“The trajectory of a rocket is just wonderful for teachers,” he says. “An overlooked way of covering the topic.”
“You can talk about electrical circuits and filaments. Then there’s language and numeracy, with calculations of velocity and height.”
He has one word of caution. “We’ve lost two rockets. When the parachutes deployed they blew into the housing estate and we never got them back. Then a Year 3 child said, ‘Sir, why don’t you label them with the school’s name and address?’ In the midst of all that scientific thinking, I’d never thought of that.”
Rocket links
Resources
* St Giles uses American “Estes” rockets from the local model shop, costing about pound;20, though the firm makes a huge range starting at about pound;6. Nasa has an excellent model rocketry website that explores and explains all the science and maths themes, with diagrams.
In UK, “Blast Off for Britain” is an organisation dedicated to preaching the gospel of educational rocketry, and also to putting together a team for international competition. Its website has lots of information, including a safety code and details for building your own simple but effective rocket out of conical chip cups.
www.blastoff4britain.org.uk
Paul Levin, the enthusiast behind “Blast Off” will run workshops for schools at about pound;10 per child. This includes a finished rocket for each child who takes part. Paul also has an online shop, the Deepsky Rocket Shop, where you can buy model rockets, kits and design software.
www.modelrockets.co.uk Tel: 01582 462720
Safety
This is mostly a matter of keeping clear, not approaching a rocket that’s misfired, and not trying to modify the rocket, or the engine. All that and more is in the UK Rocket Association’s safety code available on a link from blastoff4britain.org.uk or www.palimpsest.co.ukblastoffSafetyCode.htm
