Frictional Forces

LO: to describe the force which opposes movement and investigate the best shape

for a glider

TASK: 1.

1. Lightly push your book across the table. Why does it stop moving?

2. Rub your hands together and write down your observations

3. Make a list of useful friction and non useful friction

Space shuttle re entry

Friction occurs whenever 2 moving surfaces come in to contact with each other. Its direction is always opposite to the driving force.

Friction produces heat.

Air and water resistance (drag) are both kinds of friction.

11.3 FrictionFor each picture, discuss and then write down where friction is produced?

What links all these pictures?Streamlining and lubrication are used to reduce

friction

Lubrication video

Air resistance class challengeTASK: Who can make the best glider?

From one piece of A4 paper you have to make a shape which takes the longest time to reach the floor from the ceiling

Remember you have to increase air resistance

HINT: think about things in nature which glide to the floor

Lubrication video

Table of results

Homework

Imagine you wake up tomorrow morning in a world without friction?

Explain what would be good about this world?

Explain what would be difficult to do in this world?

Plenary- True/FalseSnow increases the friction between your shoes and the ground.

Shoelaces stay tied up because of friction

Cars need friction to keep moving.

Matches light because of friction

Cars need friction to stop.

Pencils need friction to write

There is no air resistance in space

What is the best lubricant?

Lubricant used Friction on block (N)

Friction on block with lubricant (N)

Difference in friction (N)

Vegetable oil

Washing up liquid

Water

Soap