## Year 4 Was pumped Up About the 100m

....so we thought we'd do some inquiry about the race and see what mathematical concepts we could uncover.

## We Headed for the Oval

On the 100m track, we spaced students out at 10m intervals holding signs saying 10m, 20m, 30m, etc.

At the first whistle, children started running to see how far they could get in 9.63 seconds. When the clock got to 9.63 seconds, I blew the whistle again and the runners stopped, checking how far they had got and looking to see how far Usain Bolt had got in the same time.

## Our Responses

So what did the kids have to say? And what mathematical concepts could they uncover?

"I ran 55m. That's 45m less than Usain Bolt."

"I almost got halfway."

"I got 64m before 9.63 seconds was up. I ran 6.6 m/sec. Usain Bolt ran 10.38 m/sec."

"I got between 60m and 65m."

"Usain Bolt would be twice as fast as me. In the Olympics I wouldn't even be second last!"

"I ran approximately 55m whuile Usain Bolt would have run 100m. 100m divided by 9.63 seconds is about 10.38. So Usain Bolt ran 10.38 metres every second. If I divide the metres by 1000 you get 0.01038 km. Then you multiply by 3600 seconds to get km per hour - that is about 37 km per hour. That was his average speed."

....and my favourite:

"I look down the track and murmur to myself - Usain Bolt is really fast!"

I have loved following your blog and have "pinched" so many ideas from you that I thought it was about time I gave a little back! We did a similar investigation to the one that you have outlined above and then went further to calculate how long Bolt's stride is. The children came up with the idea of counting his paces and then using this information to calculate the answer. More fun followed when we compared it to their stride length!

ReplyDeleteThanks for your continuing inspiration, Ursula

I think the size of a sprinter is a decisive factor, because Bolt only needed 41 leaps to reach the finish line, instead of 44. His start has been his weakness. If he can improve that, then I think he will be much faster...

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