Take a copper strip, a plastic rod and a wooden stick, all of the same size. Insert one end of all three in a container of boiling water. After some time feel all the three at their outward end. You will find that the copper strip is hot, the plastic rod is warm and the wooden stick's end is cool, as before. This shows that the copper strip is a good conductor of heat among the three.
Making a Simple Thermometer
Take a glass bottle and fill it with a red coloured solution. Close it tightly with a cork into which a thin glass tube has been inserted. Now maintain the glass bottle at different temperatures and note the rise of the red liquid in the thin glass tube. Start from ice cold by keeping the bottle in ice.
Put the bottle in water at various temperatures. And each time note the height of the red liquid with a suitable scale. Use an ordinary thermometer to note the temperature.