Science at key stage 3    (Year 9)

• recognise that in some contexts, eg a race of a given length, comparisons of speed can be made from measurements of time alone
• compare speeds from data of distance and time
• make measurements of distance and time and use these to calculate speeds
• use the quantitative relationship between distance, time and speed in a variety of contexts

• contribute to a group plan
• identify the difference between average speed and speed at a point
• collect readings of speed at a point using datalogging equipment
• describe the pattern in results, eg the higher the ramp, the faster the car at the bottom; the car accelerates down the slope

• suggest reasons, eg reaction time, why hand-held timers may be less accurate than electronically triggered timers
• give reasons why some specific measurements need to be more precise than others

• give examples of movement without force, eg skating
• give examples of situations, eg athletics, cars, classroom objects, in which forces increase or decrease speed
• make simple generalisations, eg the larger the force, the greater the increase of speed
• make comparisons using information from secondary sources

• identify forces and show their directions, eg friction, thrust, upthrust, weight
• state that when forces are balanced, objects do not change speed, and apply this to everyday situations, eg ball sports

• give examples of air and water resistance opposing motion
• explain that in order to increase speed without increasing thrust, resistance (or drag) has to be reduced
• describe ways in which streamlining is achieved and why streamlining is important

• describe differences in the effect of air resistance when walking or running
• identify that fuel consumption for a particular vehicle is greater at greater speed and relate this to air resistance

• explain that increased air resistance leads to a greater heating effect
• explain how, at higher speeds, the movement of an object is resisted by more particles

• identify the forces of air resistance and weight
• state that as the parachute begins to descend, it speeds up and air resistance increases
• explain that when air resistance balances weight, the parachute no longer speeds up
• identify on a speed-time graph the point at which the upward and downward forces balance
• 'tell the story' of a speed-time graph and translate a description of motion into a sketched speed-time graph

• identify factors that affect the speed of moving objects in terms of developing technology and social contexts