The most abundant element in the universe, most Hydrogen is obtained from water.

Large quantities of Hydrogen are needed in the petroleum and chemical industries for such things as processing fossil fuels, ammonia, methanol, increasing saturation of fats and oils, food additives.

Bottle of "Heavy Water" has one proton and one neutron. Used in some fission reactors as a moderator to slow neutrons and has a non-radioactive tracer in chemistry, biochemistry and environmental sciences. An ice cube made of Heavy Water would sink.

Keychain is radio-luminescent (glows in the dark). It contains Tritium isotope (one proton and two neutrons) and a phosphor which gives off light when struck by alpha particles from the Tritium.

Postcard of the Hindenburg zeppelin that exploded over Lakehurst, N.J. in 1937. Originally designed to use more expensive and safer Helium. Helium gas was banned for export by the USA and flammable Hydrogen was selected with disastrous results.