Moving Particle Facts



  • The tiny atoms and molecules from which every substance is made are constantly moving.
  • The speed at which molecules move depends on temperature.
  • Heat gives atoms and molecules extra energy, making them move faster.
  • In 1827 Scottish botanist Robert Brown saw through a microscope that pollen grains in water were constantly dancing. They are buffeted by moving molecules that are too small to be seen. The effect is called Brownian motion.
  • In a gas, the atoms and molecules are so far apart that they are able to zoom about freely in all directions.
  • As liquids boil, the atoms and molecules move around more and more energetically until some break away altogether and turn to gas. This is called evaporation.
  • Smells spread quickly because the smell molecules move about very quickly.
  • In a liquid, molecules are closely packed and move like dancers in a nightclub. If molecules stopped moving in liquids we would all die, because this movement is what moves materials in and out of human cells.
  • In a solid, atoms and molecules are bound together and vibrate on the spot.
  • Air and water pressure is simply bombardment by billions of moving molecules.
  • At —273.15°C, which is called absolute zero, the movement of atoms and molecules slows down to a complete standstill.