We want students to discover and wonder about the world around us. That is at the core of social science education. How do we explain the world around us? Kids need to explore and try to figure things out. They need to problem solve. They need to think. That is where this lesson comes from. Students 'discover' the law of demand without knowing. The Law of Demand is simple, and kids understand it because they are consumers. When prices rise, people will buy less. When prices fall, people will buy more. Simple. However, people never think about the law of demand just like they never think about why this is true. If students learn more about the law of demand, students can begin to learn about the elasticity of demand. When prices go down, HOW MUCH more will people buy. Elasticity of demand has many applications especially in a world of increasingly entrepreneurial students. How to make more money because they have learned some basic economics.
The lesson involves students communicating with one another, asking questions, graphing, and drawing conclusions. First, place students into small groups and give each group a different, small item. I picked a few items from my classroom like a stress ball, a coffee cup, a stuffed animal, etc. These items need to be interesting to students and things that they might actually buy. In their small groups, students consider and select five different price points that might elicit buying at different quantities. For example, if you give one group a bottle of soda, students might use price points such as $1, $1.50, $2, $2.50, $3. I think it is important to have 'regular' pricing intervals between the price points, but you can feel free to edit as you would like. You could also select prices for students to save on time.
Once the price points are chosen, take turns sending one group's students to each of the other groups to gather the data on how many items would be bought at each price point that the group selected. It is also important to allow someone to buy multiple items (like bottles of soda) at a price, rather than just collecting how many people would buy at different prices. The quantity we want to collect information about is not about the number of buyers, but about the physical quantities that will be bought at each price. Repeat until all groups have gathered this quantity demanded data. At this point, students combine their data in a table. From this combined, group data, students will each construct a demand curve on a graph. What students will notice is that the demand curve slopes downwards, which is proof that the law of demand is true.
This activity can provide opportunities for students to ask questions. Why is one group's demand curve more linear than another's, for example.
If you collect each group's data and diagrams, this assignment can also provide for future talking points and real data when learning about elasticity of demand. Looking at your group's data, at what prices is demand more elastic/inelastic?