Simple Screws

Contributor: Nichole Brooker. Lesson ID: 11839

Why are there nails AND screws? Won't just nails work? Why do you have to turn faucets to make them work? Learn about simple screws, find them around your home, and experiment with an ancient Greek!


Physical Science

learning style
Kinesthetic, Visual
personality style
Grade Level
Primary (K-2)
Lesson Type
Quick Query

Lesson Plan - Get It!


Have you ever used a screwdriver to fasten a screw into wood? Why can't you just push it like a nail?

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

If you missed the previous Related Lessons in our Simple Machine Fun! series, find them in the right-hand sidebar.

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 to put two things together so they stay together. Here is a picture of a piece of wood being attached to concrete for a door frame of a house:

Most people, when they hear the word, "screws," think of the typical screw used in building and creating things. Screws are used in many other places as well. The definition of a screw, according to the Merriam-Webster dictionary, is, "a simple machine of spirally grooves." A screw is like a nail but has grooves that stick out and go around the center.

There are other examples of screws that are used as simple machines as well. This is a picture of a light bulb. Can you see the spiral grooves on the base?

The bottom part of a light blub 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. Any time you see spiral grooves, you know that a screw is being used.

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 just place the two pieces together. For example, on a typical gallon milk container, the top screws on so that it stays secure and your milk doesn't spill. If the top were to simply 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, and as 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, without them, our lives would be more difficult and work would be harder.

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

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