Oxygen isn't always clear. As both a liquid ( below −182.96 °C) and a solid (below −218.79 °C), it's a pale blue.
The only two non-silver elemental metals are gold and copper.
Due to something called the Mpemba effect, warm water often actually freezes faster than cold water.
The only letter that doesn't appear on the periodic table is the letter 'J.'
You might know there're three basic states of matter: solid, liquid, and gas. Maybe you've even heard of plasma. But have you heard of Bose-Einstein condensate, fermionic condensate, time crystals, or any of the other almost twenty other rare states of matter?
When combined with water, the metal Sodium (Na), reacts so rapidly and with so much energy, that it often causes flames and an explosion.