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The Challenge: Make an underwater flashlight



With access only to a basic tool kit, some reels of wire, pots and pans, rusting kitchen equipment and a car battery would we be able to make a light at all, let alone a flashlight that worked underwater?

How is light created?

Whether using fire, electricity or even a chemical reaction, you are essentially doing the same thing: giving atoms energy and getting them 'excited'. The energy absorbed by the atoms is taken up by the electrons that surround an atom's nucleus. The energy carries the electrons further away from the nucleus than normal and the atom is in an 'excited' state. When the electrons fall back to their ground state, closer to the nucleus, energy is radiated away again.

Electrons can give off different kinds of electromagnetic radiation when they fall back to their ground state but we're particularly interested in getting them to emit radiation within the visible spectrum.

Ground and Excited States

Key

Energy

Photons