Streamlining

D. Crowley, 2008

StreamliningLO:

To understand how streamlining can increase the speed of an object

Starter

1) What did people think used to be at the centre of the universe? What was their model called?

2) What is the current model called and what is at the centre?

3) How do we describe the shape of planet’s orbit?

Speed

• Look at the two cars – imagine they had exactly the same engine (with the same power output)

• Which one would be quicker? How can you tell?

Speed

• The Aston Martin is much more streamlined than the Lada and this will affect how fast it goes (as well as having a much bigger engine in real life)…

• Its all to do with frictional forces

Friction• Whenever an object moves against another object, it is likely to

experience frictional forces - forces that act in the direction opposite to the direction of movement

• Friction can be useful - friction between our shoes and the floor stop us from slipping; friction between tyres and the road stop cars from skidding; friction between the brakes and wheel help bikes and cars slow down

• Friction can also be unhelpful - friction between moving parts causes energy loss to the surroundings (heat): rub your hands together quickly

Air Resistance

• Vehicles experience air resistance as they move - caused by the frictional forces of the air against the vehicle.

• The faster the vehicle moves, the bigger the air resistance becomes (top speed is reached when the force from the engine is balanced by air resistance)

• Reduce the air resistance and you will go faster - streamlining allows the air to flow over more easily so air resistance is reduced

Forces

• Your task is to plan an experiment, proving that being streamlined (like the Aston Martin) reduces the amount of friction

• Using the streamlined shapes worksheet complete your experiment, write your results and conclude and evaluate what you have done