Articles Required : A candle, test-tube, ice cubes, a piece of thick wire and a matchbox.
If you are given a pot full of water with an ice cube in it, and asked to heat the water in such a way that it gets converted into steam without affecting the ice cube at al!, would you be able to do it? No?
Well, you're right in a way. On the face of it, it sounds quite silly. On one side the. ice doesn't melt and on the other water containing it starts boiling! But the most amazing thing about it is that it's possible.
And this experiment would prove that water is not a good conductor of heat. Moreover, it becomes light on heating and rises upwards while the cold water takes its place.
Now if you want to prove it through experiment, do as explained here.
First of all, take a test-tube and fill three'-fourths of it with water. Now take an ice cube and coil the wire around it. Drop it in the test-tube. Normally, the ice floats on water, but because of the wire, it will sink to the bottom.
Now take a candle and light it. Tilt the test-tube a little and bring its mouth near the flame to heat the upper surface of water. You'll be surprised to see that the water at the upper surface gets heated and starts converting into steam, while the ice lying at the bottom remains as it is.