---
title: "Demand and Supply as Curves"
description: "A demand schedule and a supply schedule become two curves on the same axes: quantity demanded falls as price rises, quantity supplied rises with it. Reading a quantity off a price, and a price off a q"
canonical: https://lightmysky.com/learn/civics-and-economics/demand-and-supply-as-curves-mt_FyYrlvzXct
source: https://lightmysky.com/learn/civics-and-economics/demand-and-supply-as-curves-mt_FyYrlvzXct.md
retrieved: 2026-11-12
---

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# Demand and Supply as Curves

A demand schedule and a supply schedule become two curves on the same axes: quantity demanded falls as price rises, quantity supplied rises with it. Reading a quantity off a price, and a price off a quantity, is the basic move the rest of the model is built from.

Subject: Civics & Economics · Area: Economics · Ages 14 to 15
Page: https://lightmysky.com/learn/civics-and-economics/demand-and-supply-as-curves-mt_FyYrlvzXct

## Ready when they can

- Plot a demand curve and a supply curve from a table of prices and quantities
- State the law of demand and the law of supply and give a reason for each, not just the direction
- Read both quantities at a stated price and say which one is larger

## Lesson: Two curves, one market

Scarcity means buyers must choose how to spend limited money. A demand schedule lists quantities buyers are willing and able to buy at each price; a supply schedule lists quantities sellers offer. For example, buyers want 12 apples at 1 coin, 8 at 2 coins and 4 at 3 coins. Plot quantity horizontally and price vertically. Demand usually slopes down; supply usually slopes up, holding other influences fixed.

**Example.** A curve plots each schedule pair with quantity on the horizontal axis and price on the vertical axis. Join the points for each schedule. To find a quantity, start at a price, move horizontally to the curve, then down to the quantity axis. Reverse these moves to find a price from a quantity. At one price, compare the quantities wanted and offered. Each demand point shows planned purchases at that price, not guaranteed sales.

Holding other influences fixed, a higher price usually reduces quantity demanded: some buyers buy less or switch to substitutes. Spending more on this good leaves less for their next best use of the money. A higher price usually increases quantity supplied because it covers more costly production. This is the law of supply. These are movements along fixed curves, not changes in the whole schedules.

**Tip.** Compare both quantities at the same price and for the same period. Demand and supply describe plans; actual trades also need someone on the other side.

**Recap.** With other influences fixed, demand usually slopes down and supply up. Each point pairs a price with a planned quantity.

## Practice

8 questions on this page, each with its working shown.

## Needs first

- [Scarcity, Opportunity Cost and the Production Frontier](https://lightmysky.com/learn/civics-and-economics/scarcity-opportunity-cost-and-the-production-frontier-mt_p_c7nNzHEw)

## Optional connections

- [How markets work](https://lightmysky.com/learn/civics-and-economics/how-markets-work-mt_IWiQW8Sq2R)

## Opens up

- [Market Equilibrium, Shortage and Surplus](https://lightmysky.com/learn/civics-and-economics/market-equilibrium-shortage-and-surplus-mt_SarFx2o1IM)