Difference Between Shift in Supply Curve and Movement:

Movement Along with the Same Supply Curve:

While explaining the law of supply we have stated that as price rise, the quantity supplied increases and as price falls the quantity supplied increases and as price provided other things remain the same. This change in the quantity supplied of a commodity is a movement of one price quantity combination to another on the same supply curve. Such a movement at varying prices is now illustrated with the help of the supply curve given in figure 5.2.

Diagram/Figure:

Figure of Movement:

In the above figure (5.2) at price "aT" ($3.00), "aT" 50 units quantity is supplied. When price rises to dL ($7.0), the quantity supplied by the producers increases to OL (110 units). The change in quantity supplied at varying prices is referred as movement along the same supply curve.

Shifts in Supply Curve:

Shifts in supply curve means changes in supply. While explaining the law of supply, we have stated that that other things remaining the same (ceteris paribus) the amount of the commodity offered fore sale increases with the rise in price and decreases with a fall in price. When there is an increase in supply due to one or more than one non-price factor (which was held constant) such as production techniques, resource prices, changes in the price of other commodities, etc., there is a rise in supply. The entire supply curve shifts to the right of original supply curve indicating that more quantity is offered fore sale at the same price per time period.

If due to one or a combination of non-price factors, less quantity is brought into the market fore sale at each price, the supply is said to have fallen. In case of fall in supply, the supply curve shifts to the left of the original supply curve. The rise and fall of supply curve (shifts in supply curve) is explained with the help of an imaginary schedule and a diagram.

Schedule of Shifts in Supply Curve:

Supply schedule of shifts:
 

Price per shirt (Dollars )	Original quantity Supplied per Week	Rise in supply	Fall in supply
50	200	320	140
40	160	200	100
30	100	150	70
20	39	100	15

Figure of Shifts in Supply Curve:

In the figures (5.3) SS^/ in the original supply curve S²S² to the right of the original supply curve shows an increase in the quantity supplied at each price. S³S³ supply curve to the left of original supply curve to the left of original supply curve indicates a decrease in supply at each price over a specified period of time.