Wheel and axle

A wheel and axle work as one.

The big wheel is stuck to a small rod. When you turn the big wheel, the small rod turns too. This helps move heavy things.

Long ago, people used this to make clay pots. They used a wheel to spin the clay. This made it easy to shape the pots. People also used them to pull things in wagons. It is a very helpful tool. Do you see wheels near you?

A wheel and axle is a simple machine. It is made of two parts. One part is a large wheel. The other part is a smaller rod called an axle. These two parts are attached together. When you turn the wheel, the axle turns too.

This machine gives you mechanical advantage. This means it helps you move heavy things with less effort. You apply force to the edge of the big wheel. This force then moves a load on the small axle. The larger the wheel is, the more help you get.

People have used this tool for a long time. Long ago, people in the Middle East used potter's wheels. These were made of stone or clay. Later, people in Mesopotamia made wheels that could spin freely.

Wheeled vehicles also appeared a long time ago. Some early wagons were found in Europe. One old wooden wheel was found in Slovenia. It was made of ash and oak wood. In Egypt, people used a windlass. A windlass is a tool that uses a wheel and axle to lift heavy buckets from a well.

A wheel and axle is a very useful simple machine. It is made of two parts that rotate together around the same center. The first part is a large wheel. The second part is a smaller, thin rod called an axle. When you apply force to the edge of the wheel, that force moves to the axle. This machine is special because it can give you mechanical advantage. This means it helps you move heavy loads with much less effort.

This machine works by transferring force from the large part to the small part. You apply a force to the outer edge of the large disk. This is called a tangential force. Because the wheel is much larger than the axle, you gain strength. The ratio of the wheel's size to the axle's size determines this advantage. A bigger wheel creates a much larger force on the axle. If you need even more strength, you can connect many wheels together. These are often called gears.

People have used this invention for thousands of years. One of the first uses was the potter's wheel. In the Middle East, people used slow wheels made of stone or clay. An early example was found at Tepe Pardis in Iran. These were dated between 5200 and 4700 BCE. Later, people in Mesopotamia developed wheels that could spin freely. The oldest surviving potter's wheel was found in Ur. It dates back to about 3100 BCE.

Wheeled vehicles also became part of human life very long ago. Clay tablets from Uruk show wagons used between 3700 and 3500 BCE. In 2002, researchers found a very old wooden wheel in Slovenia. This wheel was made of ash and oak wood. It had a radius of 70 cm. The axle was 120 cm long and made of oak. This specific find is between 5,100 and 5,350 years old.

You can see this machine working in many places today. In ancient Egypt, Hero of Alexandria described a tool called a windlass. A windlass uses a wheel and axle to lift heavy buckets from wells. You turn a crank to wind up a rope. This makes the hard job of lifting water much easier. You might also see wheels on cars or wagons. While car wheels move fast, they still rely on the same basic ideas of physics.

A wheel and axle is a fundamental simple machine. It consists of two disks or cylinders with different diameters. These two parts are mounted together so they rotate around the same axis. The larger part is called the wheel. The smaller, thinner rod is known as the axle. This machine is vital because it allows for the transfer of force between these two parts. It can be used to increase force or to increase speed.

The mechanism relies on how force moves from the wheel to the axle. A user applies a tangential force to the outer edge, or periphery, of the large wheel. Because the wheel has a much larger radius than the axle, this creates a mechanical advantage. This term describes the multiplication of force or distance achieved by the machine. The ratio of the output force to the input force is determined by the radii of the two parts. If the wheel is much larger than the axle, a small input force can move a very heavy load.

Scientists distinguish between two types of mechanical advantage. The first is the Ideal Mechanical Advantage, or IMA. This calculation assumes a perfect system with no friction or energy loss. In an ideal system, the power input at the wheel must equal the power output at the axle. However, real-world machines face friction, which turns some power into heat. This results in the Actual Mechanical Advantage, or AMA. The AMA is calculated by using the efficiency of the wheel, which is the ratio of power output to power input.

History shows that humans have used this machine for millennia. One of the earliest applications was the potter's wheel. In the Middle East, prehistoric cultures used "tournettes," or slow wheels, made of stone or clay. An example from Tepe Pardis, Iran, dates to between 5200 and 4700 BCE. Later, between 4200 and 4000 BCE, people in Mesopotamia developed true, freely-spinning potter's wheels. The oldest surviving example was found in Ur, which dates to approximately 3100 BCE.

Wheeled vehicles also emerged in the ancient world. Clay tablet pictographs from the Sumerian civilization in Uruk show wagons dated between 3700 and 3500 BCE. Evidence of wheeled vehicles also appeared in the Northern Caucasus and Eastern Europe during the late 4th millennium BCE. A famous find in Slovenia is the Ljubljana Marshes Wooden Wheel. This wheel was made of ash and oak with a 70 cm radius. The 120 cm long oak axle is dated to between 3360 and 3045 BCE.

Different cultures developed various styles of wheel and axle construction. In Europe, two Neolithic types are known. One is the circumalpine type, where the wheel and axle rotate together. The other is the Baden culture type from Hungary, where the axle does not rotate. In China, the earliest evidence of spoked wheels comes from Qinghai. These wheel hubs date to between 2000 and 1500 BCE. These different designs show how various societies solved the problem of movement.

We can see the wheel and axle in many different systems. In Roman Egypt, Hero of Alexandria identified it as a tool to lift weights. He described the windlass, which uses a crank or pulley connected to a cylindrical barrel. This device provides mechanical advantage to wind up a rope and lift heavy loads, like buckets from a well. In modern powered vehicles, the system works differently. A car's transmission exerts force on an axle with a smaller radius than the wheel. In this case, the mechanical advantage is much less than 1, but it creates high rotational speed.