A fun activity to demonstrate the power of a lever: have a pencil, a tongue depressor or pop stick for each child, and a bowl of Cheerios. Show the children how to lay the pencil on table, place the tongue depressor across it at right angles so that one end is touching the table. Put a Cheerio on that end, and push the other end down sharply with a finger. The Cheerio will be launched into the air. Launch lots of Cheerios, and see where they land. Move the depressor across the pencil, and see if that makes any difference in where the Cheerios go. Try using a ruler as the lever, or a plastic spoon.
Try launching the Cheerios after removing the pencil. What happens? Why
A lever is a simple machine that makes it easier for us to lift things. If we use a lever, or a tool that includes a lever in its construction, we can lift heavy things that we would not be able to lift without it. Levers also help us to magnify (make greater) the force made by our hands alone.
Some vocabulary: lever, force, load, pivot/fulcrum.
Some examples of levers are: see-saw; wheelbarrow; stapler; scissors; shovel; screwdriver; spatula. Ask the children to try to use some of these tools to lift something heavy, or to press harder to do something that our hands alone would not able to do.
Try to open a paint can (or similar) with your fingers. Now let’s try it with a screwdriver. Which works better? Can you find the lever?
Explore wood unit blocks, and create levers by placing one on top of another crossways, and lifting books. Experiment with different lengths, and distance from fulcrum.