In: Physics
Ah, yes my kettle is no exception and the reason that kettles are noisy, they make that sort of thumping and bashing noise as they boil and then the noise intensifies as they warm up and then it goes silent as they boil. It is because of the way that the heat is being transferred into the water. So you have an electric element inside the kettle, a high current is passing through that element which makes it get hot. The heat from the element is therefore transferred by convection and conduction locally onto the water molecules around the element; they then get excited and get hot. So you have a bubble of hot water around the element which tries to expand and it also floats upwards away from the element because, of course, warm things rise but as it rises of course it loses its heat again to all of the surrounding water. So this bubble of water and water vapour collapses in on itself very quickly and that