The Law of Supply

Ability to store – some items can be made in large quantities and then stored, without any detriment to quality. For example, coal, wheat and wine are often processed in larger quantities than immediately required, and the excess production is stored. As a result, suppliers are more easily able to respond to a small change in price to take profits – leading to a more elastic supply curve. On the other hand, services can not be stored at all, and as a result the supply curve may be relatively inelastic.
Mobility of resources – When resources can easily be moved between the production of one item and the production of another, the supply curve is more likely to be elastic. This is because producers can change their minds, and start producing different items when a price in the market changes and the opportunity to make a profit exists.