Take me to the Steps

Archimedes said, “Give me a place to stand and with a lever I will move the whole world.”

The lever is one of the six classic simple machines. A simple machine is a mechanical device that changes a force’s direction or magnitude. The other five simple machines are the wheel and axle, the pulley, the inclined plane, the wedge and the screw. Explaining simple machines to kids can be a fun learning experience, especially if you include some demonstrations in the lesson. Here’s how I built a lever for a demonstration of simple machines for my son’s 3rd grade class.

Materials to build the lever
Mark semi-circular cut-aways
Three semi-circles marked for the fulcrum cut-aways
Marking semi-circular cut-outs for fulcrum
Cut semi-circles
Completed frame with fulcrum cut-aways
The standing platforms for the lever
The lever all primed and ready for paint
First coat of paint
Sand the markings off the PVC fulcrum
Completed fulcrum
Archimedes moves the earth

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Project Steps

Measure and Mark the 2x6 Boards

Simple Machines Lever - Measuring the boards

  • Ensure that your 2×6 boards are cut square at the ends, and that they are as close to 64 inches long as possible. You are going to cut three semi-circular holes in each 2×6 board.
  • Mark the center point of one 2×6 (32 inches if your board is 64 inches long) right at one edge of the board. Now make two more marks 2 1/4 inches to either side. Make another mark 2 1/4 inches from the original mark towards the other edge of the board. (Look at the images in the slideshow for some additional guidance.)
  • Now place the end of the 4 inch PVC pipe so that it is centered on the original mark. Since the pipe is 4 1/2 inches in diameter, the marks you made 2 1/4 inch to either side and above the original should exactly line up with the edges of the PVC pipe. Carefully trace a semi-circle around the end of the pipe.
  • Mark two more points 16 inches in from each end of the 2×6, right along the same edge of the board as you marked before. Repeat the procedure above to make two more semi-circular marks.
  • You should now have three semi-circles traced along one edge of the 2×6, one at the center, and two at 16 inches in from each side. Repeat this for the other 2×6 board.

Cut Out the Semi-Circles with a Jigsaw

cutting out semi-circle notch with a jigsaw

Use a jigsaw to cut out each of the three semi-circles on each 2×6 board. Cut right on the line you drew, so that the cut-away will be at least as big as the diameter of the PVC pipe. A little bigger is better than a little too small.

Build the Frame

Built frame for simple lever

  • Cut four spacers from some 2×4 board. Each spacer should be 8 1/2 inch long.
  • You will position one spacer at each end, and two along the top edge as shown above (the frame is upside down in the picture). The two spacers along the top should be centered at 24 inches in from each end.
  • Position the spacers and pre-drill two holes on each side. Pre-drilling will help keep the wood from splitting. Use four 2 1/2 inch screws to secure each spacer.

Cut and Pre-Drill the Standing Platforms

Creating the standing platforms

  • Cut the standing platforms. I used outdoor stair tread, because it is grooved for better grip. These treads are 11 inches wide. Cut the boards 15 inches wide.
  • Place the lever frame on the ground with the semi-circular cut-aways facing down. Position each standing platform at one end of the lever frame, centered from side to side and flush with the end of the frame.
  • Pre-drill four mounting holes in each platform board and directly into the frame.

Sand, Prime and Paint the Frame

Sanding, Priming, Painting

  • The frame should get a rough sanding to remove any splinters or rough spots. I used 50 grit sandpaper and a belt sander. I didn’t sand the stair tread, since it comes ready to finish.
  • While not required, you can paint the lever frame and standing platforms. One coat of primer and two top coats look nice.
  • I picked pink for the frame color. Because pink is powerful, persuasive, progressive, and perfect. Also, I had some pink paint left over from another project.

Assemble Frame and Platforms

Assemble the lever frame

  • Allow the paint to dry overnight.
  • Once the paint is dry, re-position the standing platforms over the frame and attach with 2 1/2 inch screws. Be sure the boards all line up with the pre-drilled holes you made.

Make the Fulcrum

Making the Fulcrum

  • Cut the 4 inch PVC pipe down to 15 inches long. Place a 4 inch end cap on each end. This should leave just over 12 inches of space between the end caps, which will allow the lever frame to rest on the fulcrum.
  • It is nice to sand the markings off the PVC with some medium or fine grit sandpaper.

Assemble and Test

Assemble and Test

  • Assembly is easy. Just place the frame over the fulcrum. I told my daughter what Archimedes said about moving the world, and then we tried it out.
  • First I stood on the platform furthest away from the fulcrum. I asked Anna to stand on the other side. Of course, she couldn’t move me. I asked her why and she could tell we needed to move the fulcrum.
  • Next, I had her step off and moved the fulcrum so that it was closest to me. Then I stepped on the platform, raising her side. When she stepped on, even with my greater weight, she had no trouble lifting me.

Conclusion

This project can be used by teachers, museums, home schoolers and other educators as part of a program on simple machines. Stay tuned for future projects on other simple machines.