Gas prices locally move up and down, and yet quantity demanded remains the same. Explain this context of laws of supply and demand.

The reason the price changes only cause small changes to consumer purchases is that gasoline in the US and many other industrialized has an inelastic demand. Firms that require transportation will continue to purchase gasoline, regardless of the price. For consumers, they will make small changes in their buying habits, but not a great deal. For this reason, when global oil supply changes the equilibrium price, the quantity purchased doesn't change much. In many cities, there isn't a good, close substitute for driving which is something that usually makes a product have a more elastic demand curve. Economists have done empirical research and always found that the elasticity of demand for gasoline is always less than 1.