Microeconomics
The full intro-micro spine, in the order the ideas build. From scarcity and choice, through how a market works, to the firm and where markets fail. The supply-and-demand modules all follow one running example, the market for a cup of coffee.
Scarcity and the production possibility frontier
Why does making more of one good cost ever more of the other? Drag along the frontier and watch the opportunity cost climb.
Open the module→Economic growth and shifts of the frontier
What lets an economy have more of everything at once? Better technology or more resources push the whole frontier outward.
Open the module→Comparative advantage and gains from trade
Why do two producers both end up richer by trading, even when one is better at everything? They specialise where they give up the least.
Open the module→Preferences and indifference curves
How do you draw what a person likes? As curves of equal happiness, where the slope is the rate they will swap one good for another.
Open the module→Budget constraints
What can a fixed income actually buy? A line whose slope is the price ratio, the real cost of one good in terms of the other.
Open the module→Consumer choice
Where does a demand curve come from? Put preferences and the budget together, and the best bundle is the tangency.
Open the module→Demand and supply
What actually sets a price? The two curves behind every market, and the difference between moving along one and shifting the whole line.
Open the module→Market equilibrium
What happens if you set the wrong price for coffee? Shortages and surpluses push the market to where the curves cross.
Open the module→Elasticity
Does raising the price raise revenue? It depends on elasticity, how sharply quantity responds to price.
Open the module→Consumer surplus
What do buyers actually gain from a market? The triangle above the price. Drag the price down and watch it grow.
Open the module→Producer surplus
What do sellers gain? The triangle below the price. Drag the price up and watch the cafes' winnings grow.
Open the module→Total surplus and the gains from trade
Why is the market quantity the efficient one? Add the two triangles and watch the combined gain reach its largest.
Open the module→Price controls
What happens when you cap a price, or set a floor under it? A shortage or a glut appears.
Open the module→Taxation and incidence
Tax every cup, but who really pays? The burden splits between buyers and sellers, whoever hands over the money.
Open the module→Profit maximisation
How does a firm pick how much to make? At the quantity where one more unit just stops paying, marginal revenue meets marginal cost.
Open the module→Competition and market structure
Why does a firm with rivals end up charging right down at cost? Competition turns it into a price-taker.
Open the module→Monopoly and market power
What does the only cafe in town do differently? It marks price up above cost, and some surplus is lost.
Open the module→Negative externalities
What goes wrong when a market spills costs onto bystanders? It trades too much, and the loss has a shape on the graph.
Open the module→Positive externalities and corrective policy
What if the benefits spill out to others? Too little is traded, and a tax or subsidy can steer the market back.
Open the module→Asymmetric information
What happens when one side knows more than the other? Good deals can vanish from the market entirely.
Open the module→