As water pressure changes, the volume of air in a bladder. pressure tank contracts and expands. Periodically, the amount. of air in the tank should be measured and the tank recharged if. the air is too low. Bladder pressure tanks do not provide any. useful water storage capacity.
Add Image. Exotic Materials are the strange and unusual elements produced by science, nature, or some strange alien force. Such materials could be alloys, isotopes, chemicals, and such.
What are 'Raw Materials'. Raw materials are materials or substances used in the primary production or manufacturing of goods. Raw materials are often referred to as commodities, which are bought and sold on commodities exchanges around the world. Raw materials are sold in what is called the factor market, because raw materials are factors of production along with labor and capital.