Think of all the things you do every day that use a wheel or wheels.

Wheels help you get to many places where you want to go.

But did you know that we depend on wheels for much more than just

transportation?

We need wheels for the presses that print our magazinesand books.

We need them for the washers and driers that clean our clothes, the mills that make flour)

for our bread.

And of course, we need them to have fun on skateboards and roller coasters.

The oldest wheels that we know about are potter's wheels.

A potter's wheel looks like a small, round table without legs.

To make a pot, a piece of clay is placed on the Center of the wheel.

The potter rotates the wheel while the clay is shaped.

Potter's wheels make it easier and faster to shape the round objects that you use every

day, such as bowls, plates, and vases.

Before the invention of the wheel, it was difficult to transport heavy things, such

as building stones.

These stones had to be hauled on a platform.

The platform was rolled forward on top of logs.

It was hard work, and it took a long time.

However, about 5,000 years ago, someone living in Sumer, which is the place we now call southern

Irag, had a great idea.

What if pegs were used to hold the rolling logs in place?

And what if wooden disks were fastened to the end of each log to make them stronger?

That way, animals such as oxen could easily pull a heavy load on the new wheeled cart.

Today, we call this a wheel and axle system, and it works really well.

Early wheels were made out of solid disks of wood.

They were heavy and didn't turn fast.

Then the Egyptians found a solution to this problem by making ring-shaped wheels, which

were lighter and turned faster.

They discovered that adding metal to the rim made the wheel more durable and gave it better

traction.

They attached straight rods called spokes to the center of the wheel to make it strong.

These new wheels were used in light horse-drawn carts called chariots.

Chariots were like the first cars.

People used them to get around but they also became popular for racing.

The wheel didn't just change the way people got from place to place.

In Syria and Asia, people started using the running water of a river to turn large water

wheels.

When the wheel turned it created the power to Operate a simple machine called a mill.

A water mill could grind wheat into flour much faster than a person could.

This invention means that millions of loaves of bread are made all around the world every

single day!

Lots of machines of every size and shape, from watches to printing presses, wouldn't

work without wheels.

Many machines depend on small wheels that fit together, called gears.

This is great because when one wheel turns, the next wheel turns.

The energy is transferred from one gear to another.

That is the same mechanical movement that keeps a watch ticking, 1 a car engine running,

a bicycle's wheels turning, and a press printing.

Even today, the wheel is still inspiring new technology.

Did you know that there's an electric unicycle and an automatic suitcase that will move by

itself?

There's even a new metal wheel that is designed especially for vehicles that are going to

explore the surface of the planet Mars.

Wheels will always be a central part of life, and the need for them is going to grow as

long as humans think, invent, and change.