demonstrations:seesaw_scales

Seesaw Scales

Materials: ★☆☆ Easy to get from supermarket or hardware store
Difficulty: ★☆☆ Can be easily done by most teenagers
Safety: ★☆☆ Minimal safety procedures required

Categories: Simple Machines

Alternative titles: First Class Levers

Summary

Students build a simple seesaw model to explore how levers work. By balancing weights at different distances from a pivot, they learn how effort and load relate through the principle of leverage.

Procedure

  1. Use sticky tape to secure a binder clip (opened out) to a desk, creating the fulcrum.
  2. Place a ruler across the binder clip to act as the lever beam.
  3. Tape a paper cup to each end of the ruler to hold weights.
  4. Place different weights (such as nuts, marbles, or small masses) in the cups.
  5. Adjust the ruler’s position on the binder clip until the lever balances.
  6. Measure and record the distances from the fulcrum to each cup.
  7. Compare the distances and discuss how they relate to the amount of weight in each cup.

Super Science - June 2023 - Simple Machines - Levers - Seesaw Experiment for K-5 - Massanutten Regional Library:


📄 Seesaw scales - IET: https://education.theiet.org/primary/teaching-resources/seesaw-scales

Variations

  • Use different objects for weights, such as coins, stones, or small toys.
  • Try using longer or shorter rulers to test how lever length affects balance.
  • Set challenges for balancing unusual combinations of weights.

Safety Precautions

  • Ensure the binder clip is firmly taped to avoid slipping.
  • Handle weights carefully to avoid dropping them on feet or fingers.
  • Keep small weights like marbles away from very young children due to choking hazards.

Questions to Consider

  • What happens when the heavier weight is moved closer to the fulcrum? (It can balance a lighter weight farther from the fulcrum.)
  • Why does the seesaw balance when one side has a smaller weight placed farther from the pivot? (Because the turning effect, or moment, depends on both the weight and its distance from the fulcrum.)
  • How do levers make work easier in everyday tools like scissors or nutcrackers? (They increase force or change its direction, reducing the effort needed.)