Supply and Demand

When I first met the supply-and-demand diagram, I was a junior high school student. I was then too young to know how to use the diagram. I didn't know even which curve the supply is. (Of course, the blue line is a supply curve, while the red line a demand curve.) When I came to know how the diagram is used among economists, I was a third grade university student. Until then I hadn't known the usage of the supply-and-demand diagram.

If you were a junior high or high school teacher, how would you teach it as easily to your pretty students as possible?

This might be a little hard request. If I were the teacher, I would teach like that:

First, I teach you the way demand is described. Suppose you were in the grocery store. There you meet apples. It is cheap. Since you know that they are good for your health, you buy some. Next day you are again in the same store. You meet again apples. But you notice they're a little more expensive. Though they're good for your health, you don't buy any. You buy some oranges, instead, because they're less expensive and also as good for your health as apples. So the demand for an apple decreases as the price is higher, and vice versa. That's why a demand curve slopes downward.

Second, I teach the way supply is described. Before you know that, you have to note that the supply is the other side of the same market while the demand is the one side.

Suppose you were also in the grocery store. There you sell (not buy)apples. Since you know that it is good for your business to sell them for higher price, you tend to sell for higher price. Next day you are again in the same store. You sell apples. But you notice they're a little more cheap. Since it is bad for your business, you don't sell any. You sell oranges, instead, because they're less inexpensive and also as good for your business as apples. So the supply of an apple decreases as the price is lower, and vice versa. That's why a supply curve slopes upward.

You like it? Let me know what you would like to tell if you taught the suppy-and demand diagram.

* The above diagram is from Wikipedia.