Saturday, 7 July 2012

Machines Week - Springs

This afternoon we continued with our machines project week (see previous post). We decided to investigate springs. Again we started off with a book from the great machines inside machines series.

Next we had a look at the large items around the house like sofas and beds and bounced about to test the springs. Next we found some shock absorbing springs on the car.

Looking for springs on the car

We discussed the 2 main types of springs, compression and tension springs, and investigated each type.

Stretching a tension spring

Squashing a compression spring

Then it was time to find more springs in objects around the house and take some of them apart.

Watching springs compress in the hole punch

Taking apart a pen and finding the spring

Taking apart the weigh meter

We talked about the elastic limit and demonstrated with a weak spring what happens when you pull it too much - it doesn't return to shape. We then conducted an experiment to see how a springs length changes with the amount of force applied to it. This involved counting weights and measuring. We soon passed its elastic limit.

Weights hanging off a (now unspringy) spring

R used the data from the experiment to make this graph in excel. Can you spot the elastic limit?

Finally for a bit of fun we made some springy bird mobiles. The birds flap and bounce when they are pulled downwards.

Next we'll be looking at gears, wheels, leavers and more....

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