1The price of your morning coffee depends on a quiet battle between supply and demand.
2When farmers harvest plenty of beans, supply rises and prices in the shops usually fall.
3But when frost damages the coffee farms in Brazil, the world's supply suddenly becomes much smaller.
4If millions of people around the world still want their daily cup, demand stays strong and prices climb.
5Traders in faraway cities watch weather reports because a single storm can move the market.
6Some large coffee companies buy their beans many months ahead to protect themselves from sudden price jumps.
7Small farmers, however, often have no protection and must accept whatever price the market offers.
8Economists call this relationship between buyers and sellers the basic law of supply and demand.
9The same simple idea explains the price of houses, concert tickets, airline seats, and even football shirts.
10Once you notice it, you will see supply and demand shaping almost everything you buy.
11It is one of the oldest ideas in economics, yet it still rules our daily lives.