very good question. There are a few different types of light bulbs, incandescant, flourescant and halogen, but the most common is the incandescant or filament type. A young scientist in room 3, Y., did some research and brought this answer.
Inside a light bulb are: a base that takes up electricity, connected to lead-in wires, that lead electricity to the filament. The filament is the part that gives off light. It is supported on support wires that are connected to the glass button. The glass button is supported on the glass rod. All this equipment is inside the glass casing. Inside there is no oxygen. Oxygen helps things burn, so all of it is pumped out.
See diagram attached.
World Book, Britannica Junior
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