Science at key stage 3    (Year 9)

• Show pupils videos of situations where speed is measured, eg athletics events, world speed record attempts, cars exceeding speed limits, and elicit what they know about how speeds can be determined. Discuss speedometers and show one, if possible.
• Provide pupils with times for a series of athletic events, eg men's/women's 100m, 200m, etc; pupils' own times, and ask them what they can deduce about the speeds in the events and how to explain their answers. If pupils have difficulty with this, establish that distance and time have to be measured and provide practice in this. Help pupils to consolidate their ideas by providing them with a series of statements which they have to classify as true or false, eg
• If I travel 30 miles in an hour I'm going at the same speed as someone who travels 60 miles in two hours
• A car that passes the speed markings in two seconds is going faster than the car that passes them in one second
• Introduce the formal relationship between speed, distance and time and help pupils use it in a variety of contexts. For some pupils, it will be appropriate to compare speeds in different units of measurement.

• Remind pupils of measurements of speed they made earlier, or work with pupils to make measurements of the time taken for toy cars to roll down a ramp. Discuss with pupils what the values mean and whether the car is travelling at the same speed at each point. Introduce the term 'accelerate', to be used qualitatively.
• Demonstrate how a computer-connected light gate can measure the speed of the car. Ask groups of pupils to plan and make measurements of the car's speed at a number of points on the slope, to consider reasons for variations in the readings, to make predictions about how increasing the steepness of the slope or mass of the car would affect the results obtained, and to test these predictions. Use ICT to display pupils' results and ask pupils to describe the pattern and make a generalisation about the relationship shown.

• Ask pupils to describe how times are determined in school athletics activities, and to compare this with the light gate they have just used and with the electronic equipment used in major athletics events. It would be useful to watch a video of a major athletics event and to describe how the system works. Show pupils a sequence of world records for the 100m and ask them to explain why these values need to be more precise than school athletics records.

• Demonstrate that objects can move at uniform speed with no forces acting, eg friction-free pucks on glass, a trolley on an air track, videos of ice skating, curling. Draw on pupils' experiences and support with use of ICT simulations.
• Show that introducing forces produces changes in speed - accelerations - not steady speeds.
• Introduce the idea that the larger the mass that the force acts on, the smaller will be the change in speed. Continue with the athletics and sports context and ask questions, eg
• How far can you skate on smooth ice?
• How does a sprinter get a good start?
• Why are shot-putters massive and runners slim, but both need to be muscular?
• Laboratory investigations, eg ask pupils to
• arrange friction-free movement and show that constant speed needs no force, using the equipment above
• measure the force needed to get objects of different mass moving
• try to keep applying constant force and use sensing equipment to observe the change in speed, eg up slopes, on different surfaces
• use secondary data to compare the performance of cars, eg starting acceleration with engine size or with mass of car

• Provide pupils with pictures or diagrams of moving objects, eg a car, a swimmer, a puck travelling on an ice rink, and ask them to label forces shown by arrows.
• Reinforce the correct associations, and challenge misconceptions by showing video or CD-ROM sequences and discussing these, e g ball sports, space travel, astronauts on the Moon.

• Ask pupils to suggest why streamlining is important to the shapes of humans and vehicles and, with the class, compile a chart showing examples, eg body shape of fish, sportswear worn by athletes, wind deflectors on lorries. Ask pupils to write a radio advertisement for sportswear or a car, emphasising the advantages its streamlining will bring.

• Establish with pupils that air resistance increases with speed, eg by reference to experiences of walking and running while carrying a large piece of card or an open umbrella carried horizontally, and compare data on fuel consumption of cars at different speeds. Remind pupils that fuel consumption (on a horizontal road) relates to overcoming resistive forces, not to keeping cars moving.

• Show a video/simulation of a space capsule becoming red-hot as it passes through the atmosphere. Ask pupils to use the particle model to suggest an explanation for the observation.

• Show pupils video clips of skydivers, including in free fall and landing, and ask them to explain the forces acting as the parachute descends. Provide pupils with graphs that show how the speed of descent changes with height, and ask them to interpret them in terms of changes in the upward force (air resistance), while the downward force (weight) remains constant. For some pupils, extend the activity to the interpretation of speed-time graphs - firstly for parachutes descending and then in other contexts.

• Provide groups of pupils each with a question or task relating to making things go more quickly, and ask them to present a report, or to summarise key points based on research from secondary sources. These could include:
• how scientists/inventors improved the design of vehicles/invented new vehicles, eg George Stephenson ('The Rocket'), Christopher Cockerill (hovercraft), George Cayley (aeroplane), Mike Burrows (bicycle)
• the history of cycle design, including clothing and safety features to cope with the dangers of travelling faster