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
- Gather several examples of levers (e.g., teaspoon and tin, pliers, tweezers, scissors, nutcracker, stapler).
- 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).
- For each lever, sketch a labelled diagram showing the positions of the load (L), effort (E), and fulcrum (F).
- Record how you think the lever works and identify its type (first, second, or third class).
- Complete a table comparing the lever systems you examined.
Links
- 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.)