This compares pouring marbles, peas, sand and water from one container to another.
Apparatus and materials
Perspex containers, 5 or 6, or hard plastic beakers
Marbles, dried peas, sand and water
Health & Safety and Technical notes
The containers should be large enough to hold marbles or dried peas. They need to be transparent but not glass as the marbles may break them.
One container should be empty, the others three-quarters full.
a Pour the marbles into the empty container so that the individual impacts can be clearly heard.
b Repeat with the dried peas.
c Then try the sand. (Although this is obviously discrete it sounds much more like a continuous fluid.)
d Finally pour the water.
Ask, 'How big are atoms?' Lead students to understand that if atoms were so big they could be easily seen you would certainly notice them and you might even hear them. 'Suppose atoms were as big as these marbles. Listen as they are poured into an empty container.'
This experiment gives further evidence for atoms being very small.
If alumina powder is available, it is fun to put some in a small milk jug. If some is poured into a tea cup, it can look quite like milk.
This experiment was safety-checked in June 2004