Lesson Notes By Weeks and Term v5 - Grade 8

Lesson Video

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Performance objectives

• Define market, demand, and supply.
• Describe the Law of Demand and the Law of Supply with SA examples.
• Illustrate and interpret demand and supply curves.
• Explain equilibrium price and quantity.
• Identify factors that shift demand and supply curves.

Lesson summary

This week, we delve into the fundamental concepts of markets, demand, and supply. Understanding these concepts is crucial because they explain how prices of goods and services are determined in South Africa and worldwide. From the price of bread at your local spaza shop to the cost of petrol at the garage, demand and supply play a vital role. Understanding these forces will help you make informed decisions as consumers and future entrepreneurs. It will also provide a basic understanding of how the South African economy functions.

Lesson notes

2.1 What is a Market? A market is any place or situation where buyers and sellers interact to exchange goods or services. It doesn't necessarily have to be a physical place like a supermarket or a taxi rank. Online marketplaces like Takealot, Facebook Marketplace, or even informal trading at a street corner are all examples of markets. The defining characteristic is the interaction between buyers (who want to purchase) and sellers (who want to sell). 2.2 Demand Demand refers to the quantity of a good or service that consumers are willing and able to buy at a given price during a specific period. Notice the emphasis on "willing and able." You might want a brand new sports car, but if you can't afford it (you're not able), it doesn't contribute to the demand for sports cars.

The Law of Demand: The Law of Demand states that, all other things being equal (ceteris paribus), as the price of a good or service increases, the quantity demanded decreases, and vice versa. This inverse relationship is why the demand curve slopes downwards.

Example: Consider the price of pap (maize meal) in South Africa. If the price of pap increases significantly, many families will likely buy less pap and switch to cheaper alternatives like rice or bread.

Demand Curve: The demand curve is a graphical representation of the relationship between the price of a good or service and the quantity demanded. The price is usually plotted on the vertical (y) axis, and the quantity demanded is plotted on the horizontal (x) axis.

Factors that Shift the Demand Curve: Income: If consumers' incomes increase, they can afford to buy more goods and services, leading to an increase in demand (a shift to the right of the demand curve). If incomes decrease (e.g., during a recession), demand decreases (shift to the left).

Tastes and Preferences: Changes in consumer preferences (e.g., a new fashion trend) can affect demand.

Prices of Related Goods: Substitutes:* Goods that can be used in place of each other (e.g., chicken and beef). If the price of beef increases, the demand for chicken might increase.

Complements:* Goods that are often used together (e.g., bread and butter). If the price of bread increases, the demand for butter might decrease.

Expectations: Consumer expectations about future prices or income can influence current demand. For example, if people expect the price of petrol to increase next week, they might buy more petrol this week.

Population: An increase in population will generally lead to an increase in demand for most goods and services. 2.3 Supply Supply refers to the quantity of a good or service that producers are willing and able to offer for sale at a given price during a specific period.

The Law of Supply: The Law of Supply states that, all other things being equal (ceteris paribus), as the price of a good or service increases, the quantity supplied increases, and vice versa. This direct relationship is why the supply curve slopes upwards.

Example: Imagine you are a farmer growing tomatoes. If the price of tomatoes at the market increases significantly, you would likely want to grow and sell more tomatoes to increase your profits.

Supply Curve: The supply curve is a graphical representation of the relationship between the price of a good or service and the quantity supplied. The price is usually plotted on the vertical (y) axis, and the quantity supplied is plotted on the horizontal (x) axis.

Factors that Shift the Supply Curve: Cost of Production: Changes in the cost of resources used to produce a good or service (e.g., labor, raw materials, electricity) can affect supply. If the cost of production increases, supply decreases (shift to the left).

Technology: Improvements in technology can often reduce the cost of production and increase supply (shift to the right).

Number of Sellers: An increase in the number of producers in the market will increase supply.

Government Policies: Taxes and subsidies can affect supply. Taxes increase the cost of production, decreasing supply, while subsidies reduce the cost of production, increasing supply.

Natural Disasters: Droughts, floods, or other natural disasters can disrupt production and decrease supply. 2.4 Equilibrium The equilibrium price is the price at which the quantity demanded equals the quantity supplied. At this price, there is no surplus (excess supply) or shortage (excess demand). The corresponding quantity is called the equilibrium quantity. The equilibrium point is where the demand and supply curves intersect on a graph. If the market price is above the equilibrium price, there will be a surplus, and sellers will have to lower their prices to sell their goods. If the market price is below the equilibrium price, there will be a shortage, and buyers will be willing to pay more, driving the price up.