[Music] hi and welcome back to freiz lessons. co.uk by the end of this video you should be able to describe how different domestic appliances transfer energy you should then be able to describe what's meant by the power rating of an appliance there are hundreds of different appliances that we find in homes and I'm showing you a small selection here we've got a blender a fan an IR a kettle a hair dryer and a washing machine all of these appliances transfer electrical energy into other forms of energy and you need to be able to describe these transfers now I should point out that in your exams you only need to identify transfers to kinetic energy and thermal energy so we're only going to focus on those if we look at the blender and the fan we can see that these are powered by electrical energy now in both of these cases the electrical energy is transferred into the kinetic energy of electric motors and that's because the main purpose of both of these appliances is movement the blender moves to mix the food and the farm moves to create air currents now there will also be a small amount of thermal energy generated as well due to friction in the motors but we're going to ignore that for the purposes of this video that's not our intended energy transfer looking at the ion and the kettle both of these use electrical energy from the mains but but they transfer it into thermal energy that's because both of these appliances are designed to get hot neither of these appliances generate kinetic energy that's not what they're designed to do so as you can see we can divide appliances into two main categories those are transfer electrical energy into kinetic energy and those are transfer electrical energy into thermal energy now some appliances are designed to do both and I'm showing you two examples here we've got a hair dryer and a washing machine both of these appliances use electrical energy and both of them transfer it to kinetic energy and to thermal energy so a motor moves air through the hair dryer and a heating element heats the air in the case of the washing machine a heating element heats the water and the motor turns the drum to wash the clothes now obviously there are plenty of appliances that are not designed to generate thermal energy or kinetic energy and a good example is a television however as I said before you only need to focus on appliances which are designed to generate thermal energy or kinetic energy or both now all appliances have a power rating remember that power is the rate at which energy is transferred and a power of one watt is an energy transfer of one Jew per second these are the power rating labels for the fan and the blender as you can see the fan has a rating of 20 watts so it transfers 20 Jew of electrical energy every second the blender has a power rating of 400 watts so it transfers 400 Jew of electrical energy every second looking at the power ratings of the kettle and the ion we can see that the kettle has a power of up to 2,200 watts and the ion has a power of up to 2,400 Watts now the key point you need to understand is that appliances which are designed to generate thermal energy usually have a much higher power rating than appliances designed to generate kinetic energy remember you'll find plenty questions on energy transfers and appliances in my vision workbook and you can get that by clicking on the link above in the next video we're going to look at how we can use the power rating for an appliance to work out the total energy transfer when the appliance is in use okay so hopefully now you should be able to describe how different domestic appliances transfer energy you should then be able to describe what's meant by the power rating of an appliance [Music]