eli5 why do light bulbs burn out?

Question

if the light bulb is screwed into the fixture why does it still burn out eventually?

In: 5

Answer 1

Everything that moves or gets hot etc will eventually wear out. So a light bulb gets turned on and off a lot. It gets hot, then cools down, then gets hot, then cools down etc. All this puts strain on them. And eventually they burn out.