Have you ever wondered how people in ancient times lived without modern conveniences and technology? How were buildings constructed? How did people travel without cars, carriages, or bicycles?
Imagine the challenge of transporting heavy building materials, like large rocks, from a quarry to a construction site located miles away. How would this be possible without a wheeled truck or a rolling cart? Surprisingly, people managed to do so without the assistance of a wheel and axle for thousands of years!
Although the wheel and axle is often associated with early humans or “cavemen,” it was actually invented relatively recently. This invention emerged during a time known as the Bronze Age, which occurred later in human history.
The exact origin of the wheel and axle remains unknown, but historians estimate that it dates back over 5,500 years and was likely first developed in the Middle East or possibly Eastern Europe. The wheel and axle is considered one of the six simple machines, alongside the lever, pulley, inclined plane, wedge, and screw.
Imagine a world without the wheel and axle. Many tasks would be significantly more difficult, and transportation would look vastly different from what we know today. The wheel and axle plays a crucial role in numerous practical applications.
Some may find it peculiar to classify a wheel and axle as a machine. However, in scientific terms, a machine is defined as something that amplifies force. In other words, when force is applied to a machine, it magnifies the force and directs it to another location.
Consider a hammer as an example of a machine. It facilitates the task of driving a nail into wood. Attempting this without a hammer would be futile, as bare hands lack the necessary force. With a hammer, however, one can tap the nail until it is securely embedded in the wood.
So how does a wheel and axle amplify force? Let’s think about grocery shopping. You fill your cart to capacity and effortlessly wheel it to the checkout and eventually to your car. Now imagine the amount of force required to move the cart if it didn’t have wheels.
Can you visualize dragging it across the store and to your car? The wheels enhance the force applied to push the cart, reducing friction and providing leverage along the way, making it easy to transport a heavy load.
Moreover, the wheel and axle can also increase speed and distance. For instance, when riding a bicycle, force is applied to the axle. The axle subsequently transfers this force to the attached wheel, which is larger in size. This enables the rider to travel farther and faster compared to applying force solely to the axle.
There are various examples of the wheel and axle, such as door knobs, screwdrivers, steering wheels, and even egg beaters. The mechanical advantage of a wheel and axle is the amount by which it multiplies a force. To calculate the mechanical advantage of a wheel and axle, divide the radius of the wheel by the radius of the axle.
For instance, if the radius of a wheel is 24 inches and the radius of its axle is four inches, then the mechanical advantage is 24 divided by four, which equals six. A mechanical advantage of six means that the wheel and axle multiplies a force six times or allows you to accomplish a task using one-sixth of the force you would normally need.
Give It a Try
Are you grateful that someone invented the wheel and axle? Make sure to find a friend or family member to help you with the following activities:
- How has the wheel and axle impacted your life? Keep track of all the examples of wheels and axles you encounter in your daily life for a day. For example, how do you get to school? Unless you walk, there are probably several wheels and axles involved! You might be surprised at how many different types of wheels and axles you come across in a normal day. Write down all the examples you find and share them with a friend or family member. Can they think of any examples you missed? If you need more help finding examples, you can check out these examples on Mikids.com.
- Interested in trying a fun experiment at home? Go online and check out “Wheel and Axle: An At Home Experiment” to build your own car using a water bottle, toothpicks, and plastic lids. Enjoy!
- If you have toy cars or trucks lying around, gather them up and head to the PNC Grow Up Great® Lesson Center. Explore the Wheels lesson to discover which wheels move faster.
- Curious to learn more about other types of simple machines? Go for it! Explore Simple Machines online to engage in a series of activities that will teach you the basics of different types of simple machines.
Sources of Wonder
- http://www.explainthatstuff.com/toolsmachines.html
- http://science.jrank.org/pages/4056/Machines-Simple-Wheel-axle.html
- https://www.sophia.org/tutorials/simple-machines-wheel-and-axel
- http://www.livescience.com/18808-invention-wheel.html
- https://en.wikipedia.org/wiki/G%C3%B6bekli_Tepe
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