what are the observable properties of the three different states of matter?
['Solids have both a fixed volume and a fixed shape. [01:55]', 'Solids are rigid. [02:09]', 'Liquids have both a fixed volume but a changeable shape. [03:07]', 'Liquids are fluids. [03:44]', 'Gases have both a changeable volume and a changeable shape. [04:31]', 'Gases are also fluids. [04:48]', 'CHANGE OF STATE. [07:25]']