What exactly are simple machines? How do they work? And how do you make learning about simple machines easy for your children? Learning about simple machines can be accomplished by using common examples to help your child comprehend these basic scientific concepts. Hand tools, silverware, even parts of the human body can all be considered simple physical machines.

Any physical machine makes work easier to accomplish. To a scientist, work is the amount of force (a push or a pull) used along the distance upon which the force acts, or the product of force and distance. For work to be done in a scientific sense, the object must move in the same direction in which the force acts. As you carry a heavy stack of books across the room, you do not do work on the books, since motion and force act in different directions. The motion is in the horizontal direction, along the floor, while the force is straight up, acting against the weight of the books. When you lift the stack of books straight up, you do work on the books, since the applied force and the direction of motion are the same. If you carry the books up or down a flight of stairs, then you do work on the books along the height of the stairs.

Simple, physical machines make work easier by multiplying either the force on the object or the distance involved. A see saw does work on the people sitting on either end. Have you ever changed your position on one end of a see saw to allow a small child sitting on the other end to go up and down? You adjusted one part of a lever to allow it to do work, that is, to lift up the people on each side easier. Learning about simple machines is as easy as you and your child experimenting with this concept using a ruler, a pencil, and a few coins. Place the ruler across the pencil at a right angle to the pencil and at the middle of the ruler. Place one coin after another on alternating ends of the ruler and at different distances from the pencil until the ruler balances on the pencil. What do you notice about the types of coins you use? How far away are the coins from the pencil? How many coins do you place on each side of the ruler?

Depending upon your reference, simple machines can be classified into many categories, but the two basic groupings are levers and inclined planes. A lever has two sections, or lever arms, which move around a fixed point called a fulcrum. Levers may include an automobile jack, wheelbarrow, see saw, broom, shovel, or a forearm of a human. An Inclined plane is a ramp or slanted surface along which a force moves an object to different elevations. Two inclined planes placed back to back form a wedge that is used to split things apart. Inclined planes include staircases, screws, mountain roads, and the front teeth of a human.

Most ordinary hand tools are composed of simple, physical machines. A pen or a pencil is a lever. A door knob that turns is a lever, both for pulling or pushing the door and the door knob itself. A nut cracker is a lever. A wall light switch is a lever. A crowbar is a lever. The length of a nail is a lever, while its pointed tip is an inclined plane. The length of a table knife is a lever and its blade is an inclined plane. A fork is a lever and so is a spoon. The tines on most forks end in points, therefore they are inclined planes. A hand-operated pencil sharpener is a combination of levers and inclined planes. Examine a pair of scissors closely. Can you find these simple machines? The lengths of the blades and handles are levers. The tiny post the levers turn around is a wheel and axle and also a lever. The blades are inclined planes. One edge of each blade is narrower than the other, forming a miniature ramp. By identifying these common items children are learning about simple machines without even realizing it.

You can use every day examples to aid your children in learning about simple machines. They can help explain what simple machines are and how they function. With practice children can distinguish physical objects as simple machines and determine how they operate. Simple physical machines can be located in the kitchen, in the garage, in the toolbox, and even in the human body.