Simple Machines: Levers - Sorting Activities for the Three Classes of Levers. Everything you need to know about levers is presented in this activity booklet. When teaching about Simple Machines, levers are usually taught first because students can clearly use them to identify the effort, load and fulcrum. This booklet explores the the first class lever, second class lever and third class lever, and illustrates them in posters, diagrams, a sorting table and a labeling activity. Real world example