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Market Equilibrium Explorer

Run the Market Equilibrium Explorer MicroSim Fullscreen
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About This MicroSim

This MicroSim lets students discover market equilibrium by dragging a price line up and down on a supply and demand graph. When the price is above equilibrium, a surplus develops (more supplied than demanded); when below, a shortage appears (more demanded than supplied). The simulation shows pressure arrows indicating which direction the price would naturally move, helping students understand how markets self-correct toward the equilibrium price.

How to Use

  1. Drag the red price line up or down by clicking near it and moving the mouse. Watch how quantity demanded and quantity supplied change.
  2. Observe the shaded region: orange shading shows a surplus (excess supply), while blue shading shows a shortage (excess demand).
  3. Read the info panel in the upper right showing current price, quantities demanded and supplied, and the market status (Equilibrium, Surplus, or Shortage).
  4. Click "Find Equilibrium" to snap the price line to the equilibrium price of $25 where the market clears.
  5. Click "Random Price" to jump to a random price and practice identifying whether a surplus or shortage exists.
  6. Toggle "Show Surplus/Shortage" to show or hide the colored shading.

Iframe Embed Code

You can add this MicroSim to any web page by adding this to your HTML:

<iframe src="https://dmccreary.github.io/economics-course/sims/market-equilibrium-explorer/main.html"
        height="542px"
        width="100%"
        scrolling="no"></iframe>

Lesson Plan

Grade Level

9-12 (High School Economics)

Duration

10-15 minutes

Prerequisites

  • Understanding of supply and demand curves individually
  • Ability to read a graph with two curves plotted together

Activities

  1. Exploration (5 min): Drag the price line to $40 and record Qd and Qs. Then drag to $10 and record them again. At which price does Qd equal Qs? What is special about that price?
  2. Guided Practice (5 min): Click "Random Price" five times. For each, identify whether there is a surplus or shortage and explain which direction market forces would push the price. Verify by dragging toward equilibrium.
  3. Assessment (5 min): Without using "Find Equilibrium," drag the price line to find the exact equilibrium price. Then explain in your own words why the market settles at this price and what would happen if the government tried to hold the price at $35.

Assessment

  • Students can define market equilibrium and identify it on a supply-demand graph
  • Students can correctly identify surpluses and shortages at non-equilibrium prices
  • Students can explain the self-correcting nature of markets using the concepts of excess supply and excess demand

References

  1. Economic equilibrium - Wikipedia - Overview of market equilibrium and how supply and demand determine price.
  2. Supply and Demand - Khan Academy - Video lesson on finding equilibrium and understanding surpluses and shortages.
  3. Shortage and Surplus - Investopedia - Explanation of how markets respond to excess demand and excess supply.