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The Challenge: Make an underwater flashlight

Now that we have a filament, how do we remove the oxygen from the light bulb?

Oxygen can be removed by burning a candle inside the sealed bulb. Having ensured that the candle wasn't touching the filament, a current was passed through using a car battery or several batteries in parallel. The candle going out indicates that the oxygen has been used up.

Filament inside the sealed bulb