Today’s Wonder of the Day was inspired by Claire. Claire Wonders, “Who invented these simple machines?” Thanks for WONDERing with us, Claire!
When you think of a machine, what comes to mind? Some people might think about complex machines, such as internal combustion engines or computers. However, some of the most important and useful machines are quite simple. In fact, scientists even call them simple machines!
So what is a simple machine? Is it a machine that does a simple task, such as addition or subtraction? Maybe it's just a machine that's really easy to operate, like an old television remote control? Or could it be any machine that makes life easier?
While simple machines do make our lives easier, they're much older than either television remotes or calculators. Simple machines are some of the first machines ever created.
Scientists define work as force acting on an object in the direction of motion. Machines make work easier by doing one or more of the following: transferring a force from one place to another, changing the direction of a force, increasing the magnitude of a force, or increasing the distance or speed of a force.
Since the earliest human beings walked on Earth, they looked for ways to make the work of everyday life easier to accomplish. Over time, they did this by inventing what has become known as the six simple machines.
The wheel and axle was definitely one of the most important inventions in human history. By reducing friction, the wheel enabled humans to move goods long distances more easily. Without the wheel and axle, agriculture and commerce would never have been possible.
A lever is made up of a long beam and a pivot point, known as a fulcrum. Levers allow you to lift more weight than you could on your own. For example, a 100-pound rock might be too much for you to lift by yourself. If you stick the edge of a long beam under the edge of the rock with another rock a few feet away to act as the pivot, you can apply downward pressure on the beam to move the rock. Common examples of levers include door handles, light switches, bottle openers, and hinges.
An inclined plane is a flat surface that has been raised to create an angle. If you've ever used a ramp to move something heavy, you know that dragging a heavy item up a ramp is much easier than lifting it straight off the ground.
A pulley is a version of a wheel and axle combined with a chain or a rope that changes the direction of the force needed to do work. When you pull down on a rope attached to a pulley, the object attached to the other end of the rope moves up. Pulleys can be combined with other pulleys to reduce the amount of work needed to lift very heavy objects. Common examples of pulleys include flag poles, window blinds, elevators, and cranes.
Wedges are moving inclined planes used to lift or separate. Wedges are usually used to cut, tear, or break an object into pieces. Common wedges include knives, axes, saws, scissors, and shovels. However, wedges can also be used to hold things in place, such as in the case of staples, nails, shims, or doorstops.
A screw is a twisted version of an inclined plane. It allows circular movement to be translated into an up or down motion that takes up less horizontal space. Screws can also help hold things together. Common examples of screws include jar lids, drills, light bulbs, and bottle caps.
These six simple machines are all around us. Often more complex machines, also called compound machines, consist of one or more of the simple machines put together. Can you imagine how much easier life became after the invention of these simple machines?