Simple Screws

Lesson Plan - Get It!

Audio:

A screw is like a nail but has grooves sticking out and around the center.

If you have ever used a screwdriver for inserting a screw, you have used a simple machine!

Tools are things that people use to perform specific jobs. Simple machines are tools that make a difficult task, such as moving a heavy object, easier.

Screws are one of the most-used simple machines that help people do a job. Screws are used for many things.

One example is the obvious use of putting two things together so they stay that way. Here is a picture of a piece of wood attached to another piece of wood with a screw.

When thinking about this simple machine, most people think about the typical screw used in building and creating things. However, screws are used in many other places as well.

Screws consist of spiral ridges, known as threads, wrapped around a cone-like shaft. In addition to holding objects together, they can transmit rotational motion and force.

• What does that mean?

Look at this light bulb.

• Can you see the spiral grooves on the base?

The bottom part of a light bulb screws into the base of a lamp and creates a connection that allows electricity from the lamp to pass through the bulb to light it.

You know a screw is used whenever you see spiral grooves.

Another example of a screw is a lid to a jar.

When you use threads, or spiral grooves, to connect two things, like the jar above, the two parts tend to stay together better than if you place the two pieces together.

For example, on a typical gallon milk container, the top screws on to stay secure so your milk doesn't spill. If the top were to snap on, it could come loose more easily, and you would have a large milk mess.

Screwing something together creates a tighter seal.

Another example of a screw as a simple machine is a faucet. As you unscrew the top, water begins to come out. When you screw it tighter, the water stops flowing.

Much like a mason jar lid, a bottle cap works as a screw to keep the top on the bottle and the liquid sealed until you twist off the lid.

As you can see, there are many examples of screws in the world around you, and they are used in many ways to make our lives easier.

As with all simple machines, our lives would be more difficult, and work would be harder without them.

Now that you have experienced some uses for screws put your knowledge to work in the Got It? section!