By Mark Houlahan

Inclined planes are more commonly known as ramps. An inclined plane is a flat piece of hard material that can be used to raise or lower a load. Wheelchair ramps, slides, and stairs are all examples of inclined planes. This is a great simple machine that students can identify in their day-to-day life.

• Simple and Complex Machines
• Types and Uses of Inclined Planes
• Lesson on Inclined Planes
• Inclined Planes: Simple Machines Activities

A wedge is a simple tool that is basically a moveable inclined plane. Examples of wedges in everyday life include nails, knives, and axes. A wedge is a triangular piece of material that works by combining the force applied from two different directions. Students have used wedges their whole life without realizing it, as their teeth are a type of wedge!

• Simple Machines
• Kitchen Gadgets Galore
• Introduction to the Wedge
• Wedge Lesson Plan

A wheel and axle consists of two disks of different sizes that rotate together around the same axis. This is probably the most easily identifiable simple machine for many students.

• Unit Plan: Simple Machines
• What Are the Wheel and Axle, and How Do They Work?
• Three Ideas for Building Simple Machines at Home

Compound machines are created when simple machines are combined for one purpose or several related purposes. Students can wrap up a unit on simple machines by creating a compound machine to serve a specific purpose. Try having the class compete in groups to see whose compound machine can move or lift the heaviest weight. They might even try creating a Rube Goldberg device, combining all of the different simple machines into one fun, silly contraption.

• WebQuest: Learn About Simple and Compound Machines
• Compound Machines Lesson Plan
• Read and Learn About Simple Machines
• Create a Gadget Lesson Plan