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Simple Machines

Early humans had to look for ways to do basic things with much ease. This drove them into using things like wood, bones, and stones for tasks like digging, scraping, and hunting.

As the days went by, more and more machines were invented, which led to simple machines’ innovation. In the modern world, several complex machines are made of several simple machines, which make work easy.

The basic reason for using simple machines is to reduce the effort needed to do a task.

Scientists use the term simple machine to refer to a

  • Wedge
  • Pulley
  • Screw
  • Inclined plane,
  • lever
  • Wheel and axle

These can be used solely or as a combination. One important thing to note about simple machines is that they don’t reduce or magnify the force supplied on them, but rather they use the force applied to them.

More often, students don’t realize when they are using these simple machines in their daily lives. In this article, I will highlight some examples of simple machines we used almost every day. It will help students analyze the machines around them and identify if they are simple machines or not.

Simple Machine Facts for Kids

  • A leaver can help us lift loads
  • A pulley has a rope and a wheel on a fixed axle
  • An example of a wedge is scissors
  • A screw is an inclined plane wrapped around a pole
  • An inclined plane is a ramp used to help move a heavy object
  • A Wheel and axle help us move objects with less resistance and friction

What is a Simple Machine?

A simple machine refers to a device with few or no moving parts used to modify motion and a force’s magnitude to do work easily. They accomplish this by:

  • Transferring force from a point to the other
  • Changing a force’s direction
  • Increasing force’s magnitude
  • Increasing force’s speed or distance

The sole purpose of simple machines is to make work easy. If there were not available, some tasks would even be impossible. There are six simple machines, which include:

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Facts for Kids video

1. Wedges

A wedge is a simple machine made of two inclined planes and greatly resembles an inclined plane or a ramp. One of its ends is usually thick, while the other one is sharp. Wedges make work easier by increasing the distance over which an object moves while decreasing force. Longer edges make work easier than shorter ones since they have an extra mechanical advantage. Wedges are used for different purposes such as cutting, holding together, and tightening objects.

 Human beings have been using wedges for millions of years ago. In ancient times, people would use them for hunting, cutting trees, and carving stones. The ax is also one of the ancient wedges made by man. One of the applications of wedges in real life is modern cars and jets. They usually have pointed front parts that help them cut through the air with less resistance. There are two types of wedges. These are the single and double wedges.

  • Single wedge
  • Double wedge

Examples of wedges include axes, chainsaws, knives, and scissors.

2. Screw

A screw refers to an inclined plane wrapped around a cylinder. It also has ridges around it, also known as the threads. The distance between one thread and the other is usually the same in a screw.

Screws are used for holding things together, and small ones can easily be removed using a hammer or a screwdriver. Screws are not the same as nails, the difference being that nails don’t have threads. In early timers, screws were made of wood and were mostly used for pressing clothes, wire, and olive oil.

Nowadays, they are made of metallic materials and are stronger.

They also have several applications. Screws work by converting linear motion from rotational motion.

Types of Screws

  • Bolt
  • Drill bit

3. Wheel and Axle

The wheel and axle are some of the most commonly used simple machines and have been in existence for several decades. Before its invention, there were so many transport limitations, especially when heavy goods were to be taken to longer distances. A wheel and axle is a simple machine with a wheel with a groove, with a rod running through it(axle).

In ancient times, it was used to fetch water from a well. It makes work easy by changing the distance over which force is applied. The wheel and the axles rotate simultaneously. This means that both will complete a rotation using the same time. Since the two have different radiuses, the distance they cover within the same time is different. This is what provides the mechanical advantage. A small amount of force is applied to the wheel, which is then transformed to a stronger force at the axle.

The wheel also reduces friction significantly when an object is being moved, making work easy. The innovation of the wheel and axle led to the construction of several objects such as carts and chariots, which made transport easy. Apart from reducing friction, a wheel and axle also multiply force. This means that when force is applied to the wheel, it is transmitted to the axle and is even much greater. A wheel and axle can work in two ways. These include:

  • Force applied on the wheel
  • Force applied on the axle

4. Inclined Planes

An inclined plane is exactly what its name says. It’s a plane that is inclined, or in other words, slanted. This simple machine connects a lower level to a higher level, making it easy to move objects. The slanting surface supports some weight of an object as it moving upwards, making it utilize less force. However, the object must move at a longer distance than it would on a straight surface. An object will use less force to move upward in an inclined plane with a more gradual slope.

One of the most common applications of inclined planes is getting heavy objects into a truck using a ramp. Less force is required to get the object inside of the vehicle, the tradeoff being covering a longer distance.

Other types of inclined planes include:

  • Wheelchair ramp
  • Slide
  • Slanted roof

5. Pulleys

A pulley usually has a wheel and a rope that goes through its rim. A sheave is a pulley with a grooved rim. A pulley is a simple machine that makes it easy to lift heavy objects.

To lift objects, a person usually pulls down one side of the rope, which makes the other side move upwards. It can have one or more wheels. A pulley with more than one wheel makes work even easier since the force pulling one side of the rope is increased. 

Pulleys can be used solely or as a combination to move objects. Pulleys are widely used, and if you are keen enough, you might observe some around you. Some of the pulleys we encounter in daily life include:

  • A cargo system
  • Crane
  • Engine
  • Flag pole
  • Bulldozer
  • Escalator

 The three types of pulleys include:

Fixed Pulleys

This pulley type has a drum that is secured to only one spot. It allows the changing of the direction of a force, making moving objects from one point to the other easy.

Movable Pulleys

This type of pulley has a drum that moves as the user is moving the load. A well is the most common example of a movable pulley. It works by reducing the amount of force required to lift a load. The load is placed on one side of the pulley, and force is applied on the other side. As the person fetching water applies the force, the load goes downwards, creating opposing forces.

Compound System

A compound system has both fixed and movable pulleys. It’s also referred to as a combination pulley. Compound pulleys are mostly found in construction sites for lifting heavy equipment. The more the number of pulleys a compound pulley has, the easier it gets to lift a load.

6. Levers

How Does A Lever Help Move Heavy Objects? A lever makes work easy by minimizing the amount of force required to lift the load or move objects by lengthening the distance in which the force acts. Levers will not increase or decrease the amount of energy need to move or lift objects. Instead, they spread the effort applied to them on a longer distance. Common types of levers include wheelbarrows, seesaws, and scissors. There are three types of levers. These include:

First-Class Lever

First-class levers have rigid and long beams. The beams have a fulcrum at the Centre, which enables them to balance and move easily, upwards and downwards. A user places a load at one end of the beam while applying effort on the other end. Levers are very useful in lifting very heavy loads using less effort. A carjack is one example of a first-class lever.

Second Class Lever

In second class levers, the load is between the fulcrum and the effort. Bottle openers and wheelbarrows are some of the examples of second-class levers. A human ankle area is also an example of a second-class lever. When a person stands at tiptoe position, the foot’s ball acts as the fulcrum, the body as the load, and the muscle contraction as the effort.

Third Class Lever

In third-class levers, the effort is usually between the fulcrum and the load. Examples of these levers are a pair of tweezers, a fishing road, and a broom.

What Simple Machines Are in A Bike?

Many of the machines we have nowadays are a combination of various simple machines, the bike included. It usually has the following simple machines.

  • Wheel and axle: the pedals, cassette, wheels, and crankset
  • Pulleys: braking mechanism, drive train, shifting mechanism, and chains on the gears
  • Levers: handlebars, brakes, and gear shifters
  • Inclined planes: tire repair kit, chainrings teeth, screws that hold it together

Since a bicycle is a compound of simple machines, it also makes work easier. How does it accomplish this? If you choose to walk, you’re going to need a lot of time and energy. Using a bicycle can help you reach your destination faster and using less energy.

Examples of Simple Machines in The Real World

I look at objects around me and see simple machines everywhere. Even that thing you use almost daily is made of a single simple machine, or several of them put up together to make a complex machine. Humans are innovative and will do as much as they can do work much easy. Even students will encounter some simple machines as they learn, although they might not realize it. Here are some of the most common simple machines found in the real world.

  • Pencil Sharpener – A pencil sharpener is made of two simple machines: the wheel and axle and the wedge.
  • Hammer – A hammer is an example of a lever when it’s used for driving nails into wood.
  • Spinning Wheel – A spinning wheel is an example of a wheel and axle. It is used for turning fiber into yarn and has been in existence since ancient times.
  • Clocks – A clock is also an example of a wheel and axle. Some clocks consist of levers, pulleys, and wedges, making them complex machines. 

Why Are Simple Machines Important?

Just imagine how it would be if there were no simple machines. Transporting heavy luggage would be a nightmare. We wouldn’t be objects we use every day, and performing even the easiest tasks would be so difficult. Luckily, simple machines are easily available, and they enable us to perform any task without a struggle.

Just like their names, simple machines are simple. Some are used solely, while others form parts of large machines. Some simple machines will increase the speed and distance of a force, making things move faster and farther.

Some will change the direction of the force and make things move in different directions. Other simple machines will increase the amount of force applied and enable a person to lift very heavy objects, which they wouldn’t in the absence of the machines.

What Are Simple Machines at Home?

Most of the machines used at home seem complex, but when broken down into individual pieces, they are made of several simple machines. Here are some of the simple machines found at home:

Inclined Planes

  • Staircases
  • Ramps

Wedges

  • Forks
  • Cheese graters
  • Vegetable peelers
  • Letter openers
  • Pushpins

Screws

  • Part of bulbs
  • Bottle openers
  • Jar lids

Levers

  • Scissors
  • Seesaws
  • Tongs
  • Nail clippers

Pulley

  • Wells
  • Window shades

Wheel and Axle

  • Cars
  • Fans
  • Toys
  • Fishing reels
  • Door hinges

How Do Simple Machines Make Work Easier?

Simple machines make work easier by transforming labor from one part of a device to another. They also generate force, control its motion and direction without creating any energy.

The function of a simple machine is measured by two factors: its efficiency and mechanical advantage. Efficiency refers to how well it converts energy input into valuable, useful energy.

The energy output should be equal to the energy output. However, this is not always the case since some energy is wasted through heat and friction.

Mechanical advantage is the ratio measure of output force to the input force.