demonstrations:levers_in_action

Levers in Action

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: Simple Machines: Levers

Summary

Students explore how different types of levers work by using everyday objects such as scissors, tweezers, a nutcracker, a stapler, and a teaspoon. They identify the positions of load, effort, and fulcrum, and classify the levers as first, second, or third class, depending on their setup.

Procedure

  1. Gather several examples of levers (e.g., teaspoon and tin, pliers, tweezers, scissors, nutcracker, stapler).
  2. Use each lever to perform a simple task (e.g., open a tin lid with a teaspoon, cut paper with scissors, pick up rice with tweezers, crack a ball with a nutcracker, staple paper).
  3. For each lever, sketch a labelled diagram showing the positions of the load (L), effort (E), and fulcrum (F).
  4. Record how you think the lever works and identify its type (first, second, or third class).
  5. Complete a table comparing the lever systems you examined.
  • None available

Variations

  • Try adding more examples of levers, such as a broom, wheelbarrow, or bottle opener.
  • Compare the mechanical advantage (force increase) of each lever.
  • Test levers used for speed or precision (e.g., tweezers vs. scissors).

Safety Precautions

  • Handle sharp objects like scissors and staplers carefully.
  • Supervise students when using metal tools (pliers, nutcracker).
  • Avoid using too much force that could cause tools to break or slip.

Questions to Consider

  • Which levers made it easier to apply more force, and why? (Second-class levers like nutcrackers increase force because the load is between the effort and the fulcrum.)
  • Which levers were designed for speed or precision instead of force? (Third-class levers like tweezers and scissors focus on precision and speed.)
  • How would completing the tasks be harder without using these levers? (Students should recognize that levers reduce effort or improve control in real-life tasks.)