The Wedge as a Simple Machine for Middle School Science

A wedge is a simple machine that helps us cut, split, or push things apart. It may look like a triangle or a sharp edge, but it’s actually one of the six classical simple machines that have helped people do work more easily for thousands of years.

How a Wedge Works

A wedge is made of two slanted sides that come to a sharp point. When you push a wedge into something, the force is spread out to the sides. This pushes the material apart. The sharper the wedge, the easier it is to split or cut something.

For example, when you use an axe to chop wood, the wedge-shaped blade enters the log and forces the wood fibers apart. The harder you hit, the deeper the wedge goes, and the more the log splits.

Why It’s a Simple Machine

A simple machine is a tool that makes work easier by changing the direction or size of a force. The wedge does this by turning a pushing force (straight down or forward) into a splitting force that goes outward. Like other simple machines, a wedge doesn’t reduce the amount of work—it just lets you do it more efficiently.

Wedges and Inclined Planes

At first, a wedge and an inclined plane may appear to be very different tools. However, they are closely related in both shape and function. In fact, a wedge is essentially a moving inclined plane.

An inclined plane is a flat surface set at an angle, like a ramp. It helps move objects upward more easily by spreading the effort over a longer distance. A wedge is formed by placing two inclined planes back-to-back. Rather than helping move objects upward, a wedge is used to split, cut, or push materials apart.

When force is applied to a wedge, the force is redirected outward along its slanted sides, allowing it to push apart the material it is driven into. This is similar to how an inclined plane redirects force over a distance to raise an object with less effort.

In simple terms:

• An inclined plane helps lift objects upward.

  
  

• A wedge helps force materials apart.

  
  

Although they are used for different tasks, both machines use angled surfaces to reduce the amount of force required to do work. Because of this shared principle, both the wedge and the inclined plane are classified as simple machines, and understanding one can help students better understand the other.

The History of the Wedge

Wedges are some of the oldest tools humans have ever used. Early humans used sharp stones and bones as cutting tools more than 2 million years ago. These were basic wedges used for hunting, shaping wood, and preparing food.

Over time, people improved the design by sharpening materials like metal. In ancient Egypt, stone wedges helped workers cut and shape large blocks to build the pyramids. In the Iron Age, blacksmiths used wedges to forge weapons and tools. Wedges were also used in shipbuilding, farming, and construction.

How We Use Wedges Today

Wedges are still incredibly useful and appear in many tools we use every day. Some common examples of wedges include:

• Knives

  
  

• Axes

  
  

• Nails

  
  

• Chisels

  
  

• Shovels

  
  

• Push pins or tacks

  
  

Even your teeth are shaped like wedges! Your front teeth are designed to help you bite and cut food, working just like tiny wedges.

The wedge may be small, but it’s a powerful tool that makes cutting, slicing, and splitting much easier. By understanding how this simple machine works, we can better design tools that help us shape, build, and create—just like humans have done for thousands of years.

The Wedge and Simple Machines

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Middle School Science