2.3 Demand


2026 📋 Syllabus Objectives

By the end of this topic, you should be able to:

  • 2.3.1 Define demand, draw a demand diagram, and explain what it shows.
  • 2.3.2 Draw a demand curve and use it to show movements along the curve, using the correct terms: extension and contraction in demand.
  • 2.3.3 Explain the difference between individual demand and market demand, and how they are linked through adding up (aggregation).
  • 2.3.4 Identify and explain the conditions of demand — the factors that cause the demand curve to shift left or right — using the correct terms: increase and decrease in demand.

2.3.1 Definition of Demand

What is Demand?

Demand is the willingness and ability of a consumer to buy a good or service at a given price, over a certain period of time.

Two things must exist at the same time for demand to count:

  1. The consumer must want the product.
  2. The consumer must be able to pay for the product.

This is called effective demand — it separates genuine demand from a simple wish or desire.

💡 Example: You might want a brand-new sports car worth $200,000, but if you don't have the money to buy it, that is just a desire — not demand. Demand only exists when you both want it and can afford it.


The Demand Schedule

A demand schedule is a table that shows how much of a good consumers are willing and able to buy at different prices.

Here is a simple example:

Price ($)Quantity Demanded (units)
52
44
36
28
110

Notice the pattern: as the price goes up, the quantity demanded goes down. As the price goes down, the quantity demanded goes up. This is the key relationship in demand.


The Demand Curve

When you plot the demand schedule on a graph, you get a demand curve.

  • The vertical axis (Y-axis) shows Price (P).
  • The horizontal axis (X-axis) shows Quantity Demanded (QD).
  • The demand curve slopes downward from left to right.
Price (P)
  |  \
  |   \
  |    \   ← D (Demand Curve)
  |     \
  |______\___________
               Quantity Demanded (QD)

The downward slope tells us that higher prices lead to lower quantities demanded, and lower prices lead to higher quantities demanded.

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