A filament in an ordinary light bulb is cold when there is no current passing through it. When the current flows, the metal filament gets very hot and releases a bright white light.

There are many incandescent materials. One example is carbon which is made in a candle flame. As the wax in the candle burns, tiny particles of carbon are made in the air around the wick. The temperature is so high there that the particles shine with a yellow light. The candlelight is made by incandescent carbon or soot particles. If you would like to see some, ask an adult to light a candle then put a cold plate in the flame for a second. You will see a black mark where the carbon particles have collected.