2.2 Supply
Supply shows the quantity sellers will offer at each price; the law of supply says price and quantity supplied move together, so the curve slopes upward.
Supply is the relationship between price and quantity supplied, all else equal. The law of supply says a higher price raises quantity supplied, because higher prices cover the rising marginal cost of extra units and make production more profitable, the supply curve slopes upward.
As with demand, separate movements from shifts: the good's own price moves you along the supply curve, while other determinants shift it. Supply shifters are seller-side: input costs, technology, taxes and subsidies, producer expectations, prices of alternative outputs, and the number of sellers.
Directions matter: better technology or lower input prices shift supply right (more supplied at every price); a per-unit tax or costlier inputs shift it left. A shift right is drawn down-and-to-the-right, 'increase' means more quantity at each price, not a visually higher curve.
Key terms for 2.2
Drag the curves above, or open the full Supply and Demand sandbox. Then draw it yourself for a graded check or watch the step-by-step walkthrough. Teaching this? Put this graph on your own class page, free.
Treating an increase in supply as an upward shift. An increase in supply shifts the curve RIGHT (down at each quantity), students who think 'up = more' draw a decrease by accident.
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A full lesson plan for 2.2, with timings, a warm-up, guided practice and an exit ticket.
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