Materials

We need to describe properties of materials:

• You cannot walk on water.
• If you knock a cup of coffee over what happens?
• If you pour a full kettle into a cup what happens?
• You can squeeze a sponge but not a brick.

Liquids (as can be seen from above) provide many interesting points.

It is useful to think of spaces occupied by objects. Thus we can define properties such as:

• Capacity -- a bound to an amount of liquid.
• Amount -- volume occupied by a liquid.
• Full -- if amount equals capacity.

Other properties materials can posses include:

• Free -- if a space is not wholly contained inside another object.
• Surround -- if enclosed by a very thin free space.
• Rigid
• Flexible
• Particulate -- e.g. sand