At a price of $40 per kettle, consumers demand 270 kettles per month, but producers are willing to supply 230 kettles per month. Therefore, quantity demanded exceeds quantity supplied by 40 kettles per month. Because consumers want to buy more kettles than producers are willing to sell at that price, there will be a shortage (excess demand) of kettles, and sellers will realize that they can raise their prices and still sell out their entire inventory. Thus, the shortage (excess demand) will put upward pressure on the price of a kettle, causing it to rise.

At a price of $60 per kettle, consumers demand 230 kettles per month, but producers supply 270 kettles per month. Therefore, supply exceeds demand by 40 kettles per month. Because producers want to sell more kettles than consumers are willing to buy at that price, there will be a surplus (excess supply) of kettles, and sellers will start lowering prices to sell off their excess inventory. Thus, the surplus (excess supply) will put downward pressure on the price of a kettle, causing it to fall.