Supply and Demand
In almost any market the price is set where two forces meet — the willingness to buy and the willingness to sell.
Demand
Demand is how much of a good buyers are willing to buy at different prices. The law of demand: the higher the price, the smaller the quantity demanded, so the demand curve slopes downward.
Supply
Supply is how much of a good sellers are willing to sell. The law of supply: the higher the price, the larger the quantity supplied, so the curve slopes upward.
Equilibrium
Where the curves cross is the equilibrium price P* and quantity Q*. Below P* there is a shortage, above P* a surplus; the market moves toward equilibrium on its own.
A shift ≠ a move along the curve
Price moves the point ALONG the curve. Non-price factors (income, tastes, costs, technology) SHIFT the whole curve.
🎛 The market, live
The sliders move the curves — equilibrium is recalculated live.
- explain the laws of demand and supply
- find the equilibrium price and quantity
- tell a shift of the curve from a move along it