Simple Machines

A simple machine is the simplest tool that uses leverage to make more force. Many people use simple machines every day of their life. I use a simple machine when I ride my bike. My bike uses three simple machines: the wheel, lever, and pulley.

A piano also has a simple machine. Each key is a lever. There are 88 keys in a piano. There are many other machines in our house. Blinds have pulleys in them. Door latches have levers. Scissors and knives have wedges. A toilet has a lever, so it is also a simple machine. A wagon is another simple machine. We use our wagon to carry rocks from our backyard to our front yard. I'm thankful for simple machines.

Cranes

Before cranes were invented, builders needed lots of people to pull heavy stones. They also built ramps as big as the pyramids so that they could build one. Tearing down the ramp was also a big job.

The Greeks invented the first crane. A crane can lift heavy objects like bricks. Pullies and a winch are the main parts to the crane.

After cranes were invented, it was easier to build buildings, because they could carry heavy stuff. Now they needed fewer people to build buildings, and they never had to tear down ramps again. The crane was an important invention. The end.