Problem
You are camping with your family and your best friend. Now you want to sit by a campfire. And it’s your turn to help start it!
You and your friend gather logs. You make a pile. Your aunt tries to light them with a match. Nothing happens. She smiles. “We need smaller pieces.”
But how? The wood is too hard to break with your hands. “We need a tool,” your friend says.
Solution
You remember seeing a small axe in a box of camping gear. It’s the perfect tool for the job!
You bring it to your aunt. She stands a log on end. She swings the axe. The blade strikes the wood.
THWACK! The log splits halfway. Another swing. CRACK! It splits in two. Soon the log is in pieces. The pieces are small enough to start a fire. Problem solved!
With a powerful CHOP, this axe head splits the wood. The axe head is a wedge.
It's Simple
The axe is a good tool to split wood. It’s a simple machine. Simple machines help us do jobs. They move things faster, farther, or more easily than we can without them.
You probably don’t think of an axe as a machine. A blender or a car might come to mind. These machines have lots of parts.
Simple machines have just a few parts. Some have only one part. Nearly every machine, however, is made up of one or more simple machines. The axe that you used to split thewood is a simple machine called a wedge. It’s shaped like a triangle. How does it work?
It starts with effort from you. You swing the axe. That’s the force behind driving the axe blade into the wood. The wedge shape of the axe pushes the wood sideways. CRACK! The sideways force splits the wood.
