Tuesday, 23 May 2017

Friction


We have started to learn about forces and movement as part of our inquiry topic.
Today we explored friction.

Friction is the force that is at work when two surfaces rub together. 
Friction works to slow things down and stop them moving.

We decided to investigate which surfaces create the most friction.
In groups, we discussed how we could test this. We decided on the following experiment design suggested by Ashley, Leroy, Isaac, Jason and Dhruvi;

Using the wooden sphere from our shapes set, we would roll the ball along different surfaces and measure how far it would travel.
After some discussion, we decided to let the ball go on top of a ramp rather than pushing it so we would not affect our measurements by the force we might apply.
We built our ramp out of a tissue box and a hard back book.

The first surface we tested was the table top. The ball rolled for 2m 56 cms. However, it may have kept rolling for longer- we just ran out of table!
 The second surface we tested was paper. The ball rolled for 4 m and 65 cms - Georgia

Next, we tested the carpet. We predicted the ball would move more slowly and stop sooner because it was a rougher surface - Jason

 We observed that the ball went 1m 84 cms on the carpet and it moved more slowly- Raaj
 Then we tested the black matting out on the deck. We predicted it would go slowly because the surface was bumpy and rough- Advika

The ball went 1m 84 cms. This was the same as the carpet- Kenaz
We rolled the ball on the concrete and it went 1m 40 cms before stopping- Leroy

Finally, we tested the astroturf. The ball rolled for 1m and 2cms- Krisha

We found out that the astroturf created the most friction- Vrushti

Everyday examples of friction at work;

To slow things down- more friction
- tread on car tyres (Tanisha)
-roads being made of concrete (Advika)
-concrete paths to stop you slipping (Jack)
- sole of your shoes (Georgia and Caroline)
-carpets indoor so you don't slip when you run (Leroy)

To speed things up - less friction
-racing car tyres without tread (Dylan)
-skis and snowboards are smooth (Jason)
- swimming caps or shaved heads to swim faster (Ashley)

Questions we now have about friction
What would happen if there was no friction? Dhruvi
What would happen if every surface in the world created lots of friction? Caroline
What if racing cars and family cars swapped wheels? Leroy/Ashley
What if racing cars had treads? Kenaz
What would happen if you are stuck in mud and you have racing car tyres on your bike instead of bike tyres? Mujtaba
What would happen if swimming caps were not invented and there were no hairdressers/barbers or hair ties? Caroline
What would happen if skis had grips? Vrushti
What would happen if slides were made of sandpaper? Tanisha/Raaj

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