Simple Machines - Wedges & Screws (Week 4)

## Wednesday, October 28, 2015

### Simple Machines - Wedges & Screws (Week 4)

>
This is the fourth week in our Simple Machines hands on science unit. This week we focused on wedges and screws. Come take a peak at our lesson, hopefully it will be a resource in your next homeschool science lesson either!

In case you are just joining our Simple Machines Unit for Preschool, K-5th grade, here is what you've missed:

More Simple Machines for Kids

## Simple Machines - Wedges

A wedge is an inclined plane that is thick at one end and tapers to a point on the other, often used to separate things. They include things like the front of a ship, a chisel, the pointed end of a nail, a door stop, and more.

### Simple Machines Wedge Experiments

We made two different types of paper airplanes; those with pointed and those with flat noses. We discovered that the pointed nose (a wedge) made it go quicker.

The point of a pencil is also a wedge. To show how the wedge made it more effective, we tried to see which end, the flat or pointed end would go though the paper easier.

## Simple Machine – Screws

Screws are specialized inclined planes that are used to raise and lower things as well as hold things together.  A screw is an inclined plane wrapped around a rod. They include:screws, milk lids, oil drills, and more.

### Simple Machine Screw Experiments

A screw is just a nail with an inclined plane wrapped around it. We wrapped a piece of paper around to visualize how an inclined plane becomes the circular pattern on the screw.

We observed that when the inclined plane is longer and the incline is more gradual there are more ridges on the screw. Now we made the paper shorter which made the inclined plane from the tip of the pencil to the surface more steep and as we’d learned that meant it was shorter, but more work. So when you wrap the shorter paper around the pencil it made fewer “bumps” up to the top. It was quicker to screw in, but took more effort or force to screw into the wood.

The first 5 minutes of this video offer a great visual explanation for how inclined planes and screws fit together.

Using some scrap wood, we experimented by using screw drivers to drive in screws of different types into the wood. We observed:
• Which takes more turns to screw it in?
• Which screw do you think will hold better? Why?
• Which screw has the most distance wrapped around it?
• Which requires more work?

Then we screwed a screw through a two stacked up cardboard boxes. Then we put a nail through the plates. I asked the kids what they thought would hold better? They found that a screw held better.
Here is a good explanation, but basically the inclined plane that is wrapped all around the nail helps it to hold better.

We observed the different types of screws we had in our own house: milk cap, toothpaste lid, and more. We noticed how some lids stayed on better and were less likely to spill – the ones that were screwed on.