An explanation of how the mass of atoms varies depending upon the element. Gold and silver rings are shown and an explanation of why the gold ring is heavier is given. The fact that gases also have mass is described. This is explained by stating that an opened bottle of lemonade is lighter than an unopened one. The mass of Helium being lighter than air is also mentioned.

First broadcast:
25 March 2003

This clip shows students why some elements are heavier than others, and show that gases also have a mass. Can students think of other everyday examples that highlight the fact that similar sized objects have different masses?