Understanding Movement Along the Supply Curve vs. Shift in Supply

This lesson explores the difference between a movement along the supply curve and a shift in the supply curve. A movement along the curve occurs when the price of the good changes, causing a change in the quantity supplied. A shift in supply occurs when factors other than the good's own price change, such as production costs, technology, taxes and subsidies, or the number of sellers. The graph uses the supply equation P = 2Q, where Price is on the vertical axis and Quantity is on the horizontal axis. The supply intercept represents the position of the supply curve.

How to Use the Playground

• Drag the dot to move along the current supply curve, changing Price and Quantity together.
• Use the Price controls (slider, or +/− buttons (on mobile)) to move along the supply curve.
• Use the Supply Intercept controls to shift the entire supply curve left or right.
• Observe how changing Price causes a movement along the curve, while changing the intercept creates a shift in supply.