In this lesson, students will learn about the impact that efficient markets have on attempting to correctly time the stock market, as well as how investing in stocks should have long-term investment goals. Part I begins by having students read and discuss a story. A small exercise is included which demonstrates that predicting what a stock does next is not so easy. Parts II and III take the student through an interactive historical simulation giving the student a chance to make decisions about investing in the U.S. stock market.