For thousands of years people did not know why we breathe air. Plato and Aristotle believed that nutrients from food were burned in the heart, making the flame that brought warmth and life to the body. They thought that the air that we breathe helped to keep the fire controlled. Oxygen was discovered to be [...]

Sound consists of small fluctuations in air pressure. We hear sound because these changes in air pressure produce fluctuating forces on various structures in our ears. Sound has to travel as a vibration in some material such as air or water or even stone in able for us to hear it. Since space is essentially [...]

Those pictures you see of shattering roses are roses dipped in liquid air. Materials such as iron and plastics also temporarily become brittle after being dipped into liquid air, but copper and brass become tougher. Exposure to liquid air increases the strength of certain types of magnets and make metals conduct electricity better. Air becomes [...]