machines work. Explaining: Pulley and ramp ramps reduce Exceeding demonstrations the force Work out the mechanical advantage of Demonstrate how pulleys and ramps needed to move simple machines. reduce the force needed to move an an object Explain why the actual mechanical object upwards. upwards. advantage may not be the same as the theoretical value. Plenary: Thinking about machines Use the idea that a force can be Odd One Out: ramp, lever, pulley. represented by two orthogonal forces. (Possible answers: ramp is the only one that does not move itself when the load is moved; pulley can be used to change the direction of a force as well as changing the size; lever is the only one that can be used to increase the size of the force needed/increase the distance moved.) Lesson 9Ja: Force fields Learning objectives Exemplar teaching activities Differentiation Resources Maths skills Practical skills Developing Starter: Revisit the floating paperclip n/a Resources n/a Students Recall the shape and direction of a Set up a floating paperclip at the from 9Ja determine the magnet’s magnetic field, and its effect front of the class. Ask students to Exploring rules for on magnetic materials and other explain why the paperclip stays up, Science. attraction and magnets. what will happen if you move the repulsion Describe the Earth’s magnetic field and magnet a little further from the between the its effect on compass needles. paperclip and to suggest a ‘rule’ poles of bar Recall the variables that affect the about the strength of the magnetic magnets by strength of gravity. field. suspending one State the meaning of gravitational field magnet in a strength. Exploring: Attraction and repulsion – stirrup and Use gravitational field strength to magnets bringing calculate weights. Students determine the rules for another close to Securing attraction and repulsion between the it. Describe how mass and distance affect poles of bar magnets by suspending the strength of gravity. one magnet in a stirrup and Describe the variables that affect an bringing another close to it.
machines work. Exceeding Work out the mechanical advantage of simple machines. Explain why the actual mechanical advantage may not be the same as the theoretical value. Use the idea that a force can be represented by two orthogonal forces. Explaining: Pulley and ramp demonstrations Demonstrate how pulleys and ramps reduce the force needed to move an object upwards. Plenary: Thinking about machines Odd One Out: ramp, lever, pulley. (Possible answers: ramp is the only one that does not move itself when the load is moved; pulley can be used to change the direction of a force as well as changing the size; lever is the only one that can be used to increase the size of the force needed/increase the distance moved.) ramps reduce the force needed to move an object upwards. Lesson 9Ja: Force fields Learning objectives Exemplar teaching activities Differentiation Resources Maths skills Practical skills Developing Recall the shape and direction of a magnet’s magnetic field, and its effect on magnetic materials and other magnets. Describe the Earth’s magnetic field and its effect on compass needles. Recall the variables that affect the strength of gravity. State the meaning of gravitational field strength. Use gravitational field strength to calculate weights. Securing Describe how mass and distance affect the strength of gravity. Describe the variables that affect an Starter: Revisit the floating paperclip Set up a floating paperclip at the front of the class. Ask students to explain why the paperclip stays up, what will happen if you move the magnet a little further from the paperclip and to suggest a ‘rule’ about the strength of the magnetic field. Exploring: Attraction and repulsion – magnets Students determine the rules for attraction and repulsion between the poles of bar magnets by suspending one magnet in a stirrup and bringing another close to it. n/a Resources from 9Ja Exploring Science. n/a Students determine the rules for attraction and repulsion between the poles of bar magnets by suspending one magnet in a stirrup and bringing another close to it.