The first class of Planet Money Summer School starts off with a field trip. With the help of a cow, two economists, and three cute animals, we learn what a stock is and how stocks are priced, and we begin to see the psychological forces that make prices move up and down on the stock market. Keep an eye out throughout for our big theme for the course this summer: risk and reward. | Watch this Tik Tok to learn more. | Subscribe to our weekly newsletter here.