F.4 Phy???

toy1018

The heating element in an electric kettle is fixed near the bottom. Explain why the water gets hot much more slowly if the heating element is fixed at the top.
好似明.....but唔知點解釋!!!!
thx for ur help!!!!!!!!!

hk56740

because when you put it close to the bottom,you can heat the cool water at the bottom as hot water floats and cool water sinks, making a convection current.However, when you put it at the top, you can only heat the water at the top but the cool water at the bottom can't be heated.