Resources: Mini whiteboards, a ball, a load to lift per child (e.g. weights/1 pint milk bottle/bag of sand) and materials to create a lever (e.g. string, cotton reels, dowel, wheels and cardboard).
Core Handout (2): A design sheet for the children to draw their pulleys and a results table for them to test the effectiveness of their pulleys. Page 2 asks children to evaluate their pulley system, suggesting ways to improve it.
Stretch Handout (3): A table asking children to suggest how levers work.
Enquiry Approach - Problem-solving
Applying prior scientific knowledge to solve problems and answer further questions.
Enquiry Skill - Evaluating
Assessing the success of a scientific enquiry by evaluating the prediction, method and results and identifying further questions for enquiry.
Ask the children to recap all forces from this unit by playing a game in pairs. One person says the definition of a force whilst the other has to guess which force they are explaining. Use the presentation and mini whiteboards to work through an example together.
Discuss with the children what happens when they play on a seesaw. A seesaw is an example of a lever. Levers are any sort of rigid bar that rotates around a particular point. They make it easier to lift a heavy load and allow a smaller force to have a greater effect. Explore how a lever works and examples of how levers are used in everyday life.
Then, explore pulleys. A pulley is a wheel over which a belt, rope or chain is pulled to lift or lower a heavy object.
Career Film: Take a tour around Rolls Royce SMR's Heritage Museum in Derby to find out about Matthew McCormack's job. Matthew works as the Manufacturing Engineering Manager for Rolls Royce SMR.
Expert Film: This is Matthew McCormack. Matthew works as the Manufacturing Engineering Manager for Rolls Royce SMR. Listen to Matthew as he describes levers and pulleys.
The children will design and create a pulley system to lift a load. Ideally, children in one group or across the class will have the same load to lift so that they can compare the effectiveness of their pulley.
Firstly, the children will need to lift a load and measure the force required by using a force meter. Then, they will make their pulley. Use it to lift the load, measuring the force required. Compare this to the measurement taken without the pulley. They should compare their results with other pulleys and record which one lifted the load with the least force. Using this information, the children can suggest improvements to their pulley designs. Follow the prompts on the handout to record results and conclusions.
Challenge Task: Using the presentation, ask the children to draw, label and explain some examples of when they would find levers in everyday life.
Ask the children to show and tell one of the 8 gear trains they have completed to explain what is happening.
Levers and pulleys are two types of simple machines that are used to make work easier by reducing the amount of force required to move an object.
Levers: A lever is a simple machine that consists of a rigid object, such as a board or bar, that is free to pivot around a fixed point called a fulcrum. Levers are classified into three types, based on the position of the fulcrum, load, and effort:
Levers work by allowing a small force to be applied over a long distance to move a larger load over a shorter distance. The mechanical advantage of a lever is determined by the ratio of the distance from the fulcrum to the effort to the distance from the fulcrum to the load.
Pulleys: A pulley is a simple machine that consists of a grooved wheel that is free to rotate around a fixed axle. A rope or cable is used to pull on the load, which is attached to one end of the rope or cable, while the other end is attached to the effort. Pulleys are classified into two types:
Pulleys work by distributing the load over multiple ropes or cables, reducing the amount of force required to lift the load. The mechanical advantage of a pulley is determined by the number of ropes or cables that are used in the system.
In conclusion, levers and pulleys are two types of simple machines that are used to make work easier by reducing the amount of force required to move an object. Levers work by allowing a small force to be applied over a long distance to move a larger load over a shorter distance, while pulleys work by distributing the load over multiple ropes or cables, reducing the amount of force required to lift the load.