# A Simple Machines Unit Study

I love to teach simple machines through hands-on, experimental lessons.  While it took just a bit of time to gather materials, the engagement factor made this quick and simple unit study a hit with my children.

## Simple Machines Unit Study

Before even reading the first book about simple machines, I set up some little centers for self-discovery.  The kiddos had to visit each center over the course of a few days and complete a few thought-provoking questions about what they learned. After visiting each center, we talked about the particular machine types more thoroughly and thought about when, where and how we use these simple/complex machines daily.

Center #1 – Levers

In this center, I placed hammers, can openers, bottle openers, nut crackers and paint can openers for the kids to explore and “play” with.

Afterward, they experimented with placing the fulcrum of a lever in different spots to see at which point the lever was easiest to move a pile of books.  To set this up, you tape three fat markers together in the shape of a triangular prism to make the fulcrum.  A 3-4 foot board becomes the lever and is placed on top of the markers.  A small pile of books tied together and placed on the end of the board becomes the weight you lift using the lever.

Center #2 – Wedges

To learn about wedges, my children were given a nail with a sharp end and a nail with a blunt/flat end.  Their job was to attempt hammering both nails to see which nail more easily went into the wood.  Since the sharp nail has a wedge on its end, it went into the wood much easier than the blunt nail.

Center #3 – Inclined Plane

To measure the effectiveness of an inclined plane, my children completed this simple experiment.  A stack of books with string tied around them was pulled up a simple ramp made from a piece of scrap wood.  Then the stack was lifted straight up into the air to the same level as the top of the ramp.  Since we don’t own a spring scale, we tied a rubber band to the string and measured the stretch length for each of the attempts. Upon seeing that the rubber band didn’t stretch as far when the books were pulled up the ramp, they concluded that less force was necessary using the inclined plane as compared to pulling the books straight up.  Therefore, they decided the inclined plane must be a helpful too.

They experimented a bit more with inclined planes using two screws – one with threads very close together and one with threads far apart.  The task was to see how many turns it took to get each screw into the wood.  More turns were required for the closer threaded screw, but the job was much easier than the screw with threads far apart.

Center #4 – Wheel and Axle

Using the same rubber band measuring trick as mentioned above, the kiddos determined whether or not less force was required to pull a piece of wood using wheels.  They first pulled the wood along the carpeted floor and measured the pull length of the rubber band.  Next, they placed the wood on a toy with wheels and measured the pull length of the rubber band.  The rubber band measurement was much shorter when pulled with the wheels meaning less force was required to move the wood.

Center #5 – Gears

To explore gears, I simply pulled out the gear set we have in our toy closet and let them play.

Center #6 – Pulleys

Because we have plenty of pulleys and ropes around the farm, to explore pulleys as a simple machine I asked the kids to create a useful pulley for their treehouse.

Center #7 – Friction

This experiment determined which of the following materials provides for the least amount of friction when placed on a piece of scrap wood.  My children rubbed the following materials all over one side of four pieces of wood: one piece of wood was rubbed with dish soap, one with vegetable oil, one with wax and another with soap.  The same rubber band trick was used to determine the pull length as each piece of wood was dragged across our art table.  The one with the least pull length encountered the least friction.  The one with the most pull length encountered the most friction.

To further explore friction, I assigned this challenge:  Design a parachute that allows for the most friction so our “little person” arrives safely on the ground. Neither of their original designs worked.  Neither of their 2nd designs worked.  Neither of their 3rd designs worked.  Finally, after learning a thing or two from their failures, they successfully landed a parachute.

Center Discovery Booklet

To guide their discovery, I made up a little booklet of leading questions for each of the centers. Since I used so many ideas from various books I have around the house, I can’t share the booklet.  It was pretty easy to make, though.  Just ask your children to note results from the experiments and then ask open-ended questions like, “Why do you think it was easier to pull the board using wheels?”  The goal isn’t correct answers just yet, it’s coming to reasonable conclusions after experimentation.

### Simple Machines Literature

After the self-discovery activities, we dove into a few books that helped teach the science behind simple machines and friction.

Two of our very favorite picture books ever have machines as their main characters.  Reading them again with an eye on the use of simple machines gave my children an entirely new perspective of the books.

### Simple Machines Resources

If you’re looking for some great lesson ideas to teach simple machines, these books are fabulous!  Just choose one of them and you’ll have a all the ideas you need for your own simple machine unit study.

This post was originally written in 2009.  As I prepare to do a simple machine unit study with Eli soon, I’ll use every single one of these activities again.  My older two responded so well to the discovery-based lessons that I can’t pass up giving Eli the same experience.

I hope your children enjoy the lessons, too!