According to the personal library, incandescent bulbs are very hot, and changing bulbs by hand is very hot. Electroluminescence (energy-saving lamps, LEDs) is not very hot, but there is a danger of electric shock when replacing light bulbs with electricity. So it is not safe to change the light bulb by hand.

The light bulb, a kind of lighting source that glows and gives off heat through electric energy, was invented by Henry Goebbels in 1854, and Thomas Alva Edison found a more suitable material to develop incandescent lamps.