Demand — Social Studies definition

The relationship between prices and quantities buyers are willing and able to purchase under stated conditions.

Where it is taught

In use

Demand describes quantities buyers are willing and able to purchase at different prices, other relevant conditions held constant.

Supply, Demand, Equilibrium & Market Changes

Questions using demand

Problem 1

Why is the supplied demand increase a shift rather than a movement along the old curve?
Answer and explanation

Quantities change at every given price while the supply schedule is unchanged. A movement along the original demand curve would follow a change in the product’s own price under its held-constant conditions.

Problem 2

Invented weekly schedule: prices $1–$5; original demand 80,60,40,20,0; supply 0,20,40,60,80. Demand then rises by 40 at every price. Identify both equilibria and a shortage at the original $3 after the shift.
Answer and explanation

Originally, $3 and 40 units equate supply and demand. After the shift, demand at $3 is 80 while supply remains 40, a shortage of 40. At $4, both are 60, so the new listed equilibrium is $4 and 60 units. The prediction holds within this supplied model; it does not establish the cause of an actual market change or instant adjustment.

Find equality in the original schedule.

Add 40 to demand rows.

Compare quantities at $3 and $4.

Response criteria

  • Explain the relevant institution or economic concept accurately; show correct calculations where needed.
  • Connect supplied evidence and stated assumptions to an explained conclusion.
  • Compare feasible options and their effects on different people without stereotypes.
  • Identify a limitation, tradeoff, uncertainty, or condition that qualifies the conclusion.

Problem 3

Does a product’s own price increase automatically shift its demand curve?
Answer and explanation

No. Under unchanged other conditions, it produces movement along the demand relationship. A shift requires a change in another relevant condition, such as preferences or income under a specified assumption.

Response criteria

  • Explain the relevant institution or economic concept accurately; show correct calculations where needed.
  • Connect supplied evidence and stated assumptions to an explained conclusion.
  • Compare feasible options and their effects on different people without stereotypes.
  • Identify a limitation, tradeoff, uncertainty, or condition that qualifies the conclusion.

Problem 4

In the unit schedule at $4, demand is 20 and supply 60. Calculate excess supply and explain why it is not proof of waste in every real market.
Answer and explanation

The model surplus is 40 units per week at that price. Actual inventory, contracts, allocation, and adjustment are not supplied. The gap describes planned quantities under assumptions, not every physical outcome or welfare consequence.

Response criteria

  • Explain the relevant institution or economic concept accurately; show correct calculations where needed.
  • Connect supplied evidence and stated assumptions to an explained conclusion.
  • Compare feasible options and their effects on different people without stereotypes.
  • Identify a limitation, tradeoff, uncertainty, or condition that qualifies the conclusion.

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