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Principles of Microeconomics


Supply and Demand


The supply and demand model predicts what quantities of goods will be sold in the market, and what prices these goods will be sold for. Prices and quantities are determined in an equilibrium where the choices for purchases by consumers at given prices (demand) are consistent with the choices of production by businesses at given prices (supply). In these Pencasts, we discuss what other factors besides price that can affect the demand and/or supply of goods and services. The model can be used to predict how prices and quantities of production change in response to changes in the economy.


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Introduction to the Supply and Demand Curves

In this Pencast we introduce the concepts of the supply curve and the demand curve, demonstrate how we model these concepts with graphical illustrations, and show the concept of market equilibrium. [Play Pencast]


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Shifts to the Demand Curve

This Pencast describes other factors, besides price, that can affect consumers' demand for goods and services. We demonstrate the effect of these changes on the demand curve, and the outcome for equilibrium price and quantity. [Play Pencast]


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Shifts to the Supply Curve

This Pencast describes other factors, besides price, that can affect businesses' decisions for the quantity of goods and services to produce. We demonstrate the effect of these changes on the supply curve, and the outcome for equilibrium price and quantity. [Play Pencast]


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Supply and Demand for Food - Part 1

In this Pencast we use the supply and demand model to investigate the effect that ethanol subsidies have on the market for food made from corn. [Play Pencast]


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Supply and Demand for Food - Part 2

In this Pencast we use the supply and demand model to investigate the effect that an increase in the world population has on the market for food. [Play Pencast]


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Supply and Demand for Ethanol

In this Pencast we use the supply and demand model to investigate the effect that ethanol subsidies have on the market for corn crops, the market for meat, and the market for grains besides corn, such as soybeans, wheat and peas. [Play Pencast]


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Market Dynamics When Price is Below Equilibrium

In this Pencast we investigate what happens when the price is below equilibrium. We find this causes a shortage of the good or service, meaning the quantity supplied is less than the quantity demanded at that given price. We illustrate this problem, suggest some reasons why it may occur, and describe the market dynamics as the economy moves toward its equilibrium. [Play Pencast]


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Market Dynamics When Price is Above Equilibrium

In this Pencast we investigate what happens when the price is above equilibrium. We find this causes a surplus of the good or service, meaning the quantity supplied is greater than the quantity demanded at that given price. We illustrate this problem, suggest some reasons why it may occur, and describe the market dynamics as the economy moves toward its equilibrium. [Play Pencast]


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