(total energy order of 0.8 or above). power is a measure of Ask students to describe supplied to the device) energy transferred each what the two diagrams P1.33 Equipment: electric kettle(s) second, and ask for show, elicit ideas about Explain that mechanical with auto-shut-off (If various suggestions why this the differences between processes become wasteful kettles with different power was done. Question the energies transferred when they cause a rise in ratings can be provided, then students to elicit the by the two objects, and temperature so dissipating this experiment can be idea that the limit on discuss what could be energy in heating the repeated to find out, for power will encourage used as the measure of surroundings … example, if higher power kettles manufacturers to energy wasted – elicit the P1.36 are more or less efficient.); develop more efficient idea that comparing the Explain ways of reducing measuring cylinder/beaker machines, so that they amount of useful (or unwanted energy transfer (500/1000 ml); stopclock end up with a vacuum wasted energy, at this including through lubrication Optional: temperature sensing cleaner that uses less point in the lesson) to the ... datalogger. energy for the same total energy transferred performance. to the appliance is a more useful measure than just looking at the amount of Digital Efficiency wasted energy. calculations presentation CP3c P1.33 Explain that mechanical Hold a short Students to compare the energy Demonstrate the effect Supplying processes become wasteful brainstorming session to transferred by a bulb close to a on transmission losses electricity when they cause a rise in elicit words connected power pack and connected to of increasing the temperature so dissipating with the transmission of the power pack by lengths of voltage of a supply by energy in heating the electricity around the resistance wire. using a 12 V a.c. supply surroundings or when they country (e.g. power connected to two do electrical work against station, pylon, cables, metre-long lengths of Students should find that the resistance of connecting substation). Ask students resistance wire. energy transferred to the wires. to suggest what these Connect a bulb across distant bulb is significantly less things are for, and then the supply and another than to the bulb close to the P1.34 Explain why electrical to work in pairs or small across the ends of the power pack. energy is transmitted at groups to write a short resistance wires. Switch
P1.33 P1.36 (total energy supplied to the device) Explain that mechanical processes become wasteful when they cause a rise in temperature so dissipating energy in heating the surroundings … Explain ways of reducing unwanted energy transfer including through lubrication ... Ask students to describe what the two diagrams show, elicit ideas about the differences between the energies transferred by the two objects, and discuss what could be used as the measure of energy wasted – elicit the idea that comparing the amount of useful (or wasted energy, at this point in the lesson) to the total energy transferred to the appliance is a more useful measure than just looking at the amount of wasted energy. order of 0.8 or above). Equipment: electric kettle(s) with auto-shut-off (If various kettles with different power ratings can be provided, then this experiment can be repeated to find out, for example, if higher power kettles are more or less efficient.); measuring cylinder/beaker (500/1000 ml); stopclock Optional: temperature sensing datalogger. power is a measure of energy transferred each second, and ask for suggestions why this was done. Question students to elicit the idea that the limit on power will encourage manufacturers to develop more efficient machines, so that they end up with a vacuum cleaner that uses less energy for the same performance. Digital Efficiency calculations presentation CP3c Supplying electricity P1.33 P1.34 Explain that mechanical processes become wasteful when they cause a rise in temperature so dissipating energy in heating the surroundings or when they do electrical work against resistance of connecting wires. Explain why electrical energy is transmitted at Hold a short brainstorming session to elicit words connected with the transmission of electricity around the country (e.g. power station, pylon, cables, substation). Ask students to suggest what these things are for, and then to work in pairs or small groups to write a short Students to compare the energy transferred by a bulb close to a power pack and connected to the power pack by lengths of resistance wire. Students should find that the energy transferred to the distant bulb is significantly less than to the bulb close to the power pack. Demonstrate the effect on transmission losses of increasing the voltage of a supply by using a 12 V a.c. supply connected to two metre-long lengths of resistance wire. Connect a bulb across the supply and another across the ends of the resistance wires. Switch
GCSE-9-1-Science-Term-2-detailed-planning-document.docx