1. Science - Year 3/4A Autumn 1
Forces and Magnets
Magnetic Fun and Games
Session 1
Plenary PowerPoint
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2. Let’s think about what we have discovered
On which of these surfaces would the car travel fastest and run on furthest?
On which surface would the car travel slowest and run on the shortest distance?
Discuss your answer and give a reason
Discuss your answer and give a reason
A because it is the smoothest surface
C because it is the roughest surface A B C

3. Why does the texture of a surface make a difference to objects moving on a it?
It is because of a force called friction. Friction holds back the movement of a sliding object. You will find friction wherever two surfaces come into contact with each other. There is more friction between rough surfaces than smooth ones.
Which is the best skating surface?
This one, because it is smoother. There is less friction to hold back the movement of the skates.

4. Which type of shoe would be safest for walking on this steep, muddy path?
This one, because its rough, bumpy sole would have more friction. Remember friction holds back movement so you would be much less likely to slip.

5. This skier wants to race down the mountain.
Are the skis are designed to:
create lots of friction?
reduce friction to a minimum?
b) Reduce friction to a minimum so they are made as smooth as possible

6. Has this bath mat been designed to:
a) create lots of friction? b) reduce the friction?
The rough surface creates lots of friction so it is harder for a foot to slide across it. It is a safe non-slip surface
Has this bowling lane been designed to:
a) create lots of friction? b) reduce the friction?
The smooth surface reduces the friction so the ball slides easily over it

7. So how will our discoveries help P & L Toys?
What sort of surface should they use for their racing track if they want cars to go fast?
A smooth one

8. 2 1 5 4 7 6 9 8 10 3 12 11 15 14 13 16 17 19 18 21 20 23 22 25 24 27 26 29 28 30
What sort of surface should they use for their board game if they don’t want the playing pieces to roll away?
A rough one

9. Congratulations everyone
Congratulations everyone! You have made some important scientific discoveries about forces. P & L will be delighted with your research as it will help in the design of their new range of vehicle toys!