Journey into space

19th May 2006 at 01:00
You don't have to be a rocket scientist to understand the maths needed to get into orbit. Crispin Andrews reports on a masterclass for Year 7 students

4What might you need to get into space? A few tennis balls, a model rocket, some big numbers, imagination and some logical thinking should do it.

For some of the assembled Year 7s, especially those who are good at sport, throwing a tennis ball as high as they can into the air is just a question of macho pride. Others show competitive spirit and are not fussed how high the ball travels as long as they can outdo their friends.

For two girls who "don't do sport" it is all too embarrassing, and the futility of their efforts sends them into fits of giggles. But, like all the others, they are missing the point. It takes the nerd - or, as he would call himself, the most thoughtful and focused participant, to realise the true significance of what is going on.

"It doesn't matter whether they throw the ball twice as high as I do, they're hardly making it travel any faster," he says. "The difference in the time it takes the ball to reach the ground again is minute, maybe a few tenths of a second."

The two girls smile - they like the thought of doing almost as well as the big-headed boys, without even trying. Perhaps Simon isn't as nerdy as they thought - perhaps being good at maths is cool after all.

Present at this special one-day masterclass are the most able Year 7s from the two Langley Park Schools - one for boys and one for girls - in Bromley, Kent. While the theme is the maths of space travel, its title - Get Me Out of Here -owes more to a popular TV show.

However, far from eating worms and getting on each others nerves, these children are involved in some worthwhile learning. Teacher Mike Rodger, who is running the project, says: "As a specialist maths college we need to extend our most able students - give them something to get their teeth into." Mike took a degree in maths and physics at Melbourne University and is now head of specialist maths at the boys' school and is convinced that to stretch gifted children academically, it is essential to engage their imaginations.

He says: "We are talking about students who know they are very good at maths and always do well in class. It would be easy for them to cruise through school life without ever pushing themselves. We want to show how maths can be applied, not just in everyday real-life situations, but in exciting ways that can help take them on adventures into the unknown."

It only takes a few minutes to realise that it is simply not possible to get a tennis ball particularly high into the sky - let alone into space - people don't have that kind of strength; even firing it out of a cannon would be no use. Theoretically, you could apply enough force to offset the Earth's gravity, but the velocity at which the ball would have to travel would simply burn it up. As for the old folk tales about the man in the moon, the body can take no more than 10 times gravitational force, so if you "fire the man up into the sky... just like the tennis ball... he will fry".

"Most of the students know some sort of rocket is needed to get people to the moon, but they never really knew why," Mike says.

The next part of their attempt to Get Out of Here involves building their own rocket. Working in groups, the students roll single pieces of cardboard into a cylinder, making nose cones and fins to keep their rockets as aerodynamic as possible. They have already worked out that any instability or sideways motion will slow the trajectory and, as with the tennis balls, once these rockets are set off by a compound air gun, there is kudos at stake.

No one wants to be associated with a rocket that goes nowhere, but this is what happens - the rockets are in the air scarcely longer than the tennis balls: students are disappointed. They knew their rockets wouldn't be near to going out of sight, but four or five seconds, come on. Using the time spent in the air as a way of working out speed, they realise that, even with a propulsion system, their rockets are travelling only about twice as fast as the tennis balls they had been slinging upwards earlier in the day.

A few moments later, Langley Park headteacher Rob Northcott strides onto the playground carrying an altogether more sophisticated-looking selection of rockets. The students start to realise what their own efforts are missing. A keen member of a local amateur rocket society, Rob has created models up to about two metres long and, like real rockets, they have fuel.

The students immediately consider how much fuel would be needed for a rocket big enough to carry people into space. They soon realise why rockets are so long and the space for the astronauts so small. "I never knew so much fuel was on board, but it makes perfect sense - how else would the thing get up there," says one student.

It is the sort of eureka! moment Mike and other staff in the masterclass want to engender. "We want to spark curiosity. Above all, we want to give these Year 7s the message that maths is fun."

lFor more maths-based space travel activities, visit: mathbits-comvirtualrobertsspacemathtitlepage.html

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