Simple Machines Lever Experiment
Build a lever from a ruler and a pencil and discover how moving the fulcrum changes lifting power. The simplest machine with the biggest lesson in physics.
What You'll Need
- 1A 12-inch ruler
- 2A round pencil (for the fulcrum)
- 3Small toys or weights of different sizes
- 4A flat table surface
What You'll Need
A 12-inch ruler
A round pencil to use as the fulcrum
Small toys or weights of different sizes
A flat table surface
How to Play
Place the pencil on the table. Lay the ruler across it at the center — this is your lever.
Put a toy on one end. Push the other end down. "Balanced effort — easy."
Move the pencil closer to the toy (3-inch mark). Push again. "Even easier!"
Move the pencil away from the toy (9-inch mark). "Harder! More effort needed."
"Fulcrum close to the load = less effort. That's mechanical advantage."
Try heavier objects. "Where should the fulcrum go to lift something really heavy?"
Find levers in real life: see-saw, bottle opener, wheelbarrow.
The Science Behind It
A lever is one of the six simple machines. It amplifies force: by positioning the fulcrum closer to the heavy end, you trade distance for force — you push farther, but with less effort. This is why a long crowbar can pry up heavy objects, and why a see-saw works when kids of different weights sit at different distances from the center.
Tips
A round pencil works better than a hexagonal one because it rolls less.
Experiment with extreme positions: fulcrum right next to the load makes lifting almost effortless but requires you to push the ruler way down.
Stack multiple toys to make a "heavy" load and see where the fulcrum needs to go.
Point out real-world levers: scissors (two levers), bottle opener, stapler, nail clippers.
For advanced kids: a wheelbarrow is a lever with the fulcrum at the wheel. Where's the load? Where's the effort?
Age Adaptation Tips
School-age kids can take more ownership. Let them lead the activity, experiment with variations, and explain what they learned.
Frequently Asked Questions
How long does this activity take?
This activity takes about 15 min, with 0 min of preparation time beforehand.
What materials do I need?
You'll need: a 12-inch ruler, a round pencil (for the fulcrum), small toys or weights of different sizes, a flat table surface.
What age is this activity for?
This activity is designed for 5-8 years. You can adapt it for younger or older children by adjusting the complexity.
Can this be done indoors?
This activity is designed for indoor play, making it perfect for rainy days or when you're staying inside.
How difficult is this activity?
This is an easy activity that requires minimal setup and supervision. Great for busy days or when you need something quick.
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