demonstrations:screw_ramp_around_rod
Screws - A Ramp Around a Rod
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: Inclined Plane Wrapped Around a Cylinder
Summary
A screw is a simple machine made by wrapping an inclined plane (a ramp) around a central rod. This design allows a small force applied over a long distance to be converted into a larger force, which can hold objects together or lift them. Everyday examples include screws, bolts, jar lids, and spiral staircases.
Procedure
- Begin with pictures of long ramps or staircases and explain how ramps reduce effort by spreading work over distance.
- Show a spiral staircase or spiral parking garage as an example of how ramps can be wrapped around to save space.
- Compare a steep path up a mountain with a switchback path, which works like a screw by making the climb easier.
- Give each student a triangle of paper with the long side marked as the “ramp.”
- Have them roll the triangle tightly around a pencil; point out how the ramp becomes a spiral, forming a screw.
- Discuss how screws use this principle to hold things together or lift objects with less effort.
Links
📄 A ramp wrapped around a rod - Inventors of Tomorrow: https://inventorsoftomorrow.com/2016/10/24/screws-simple-machines-activities-for-kids/
Variations
- Use clay or playdough to make spiral shapes that resemble screws.
- Demonstrate with real screws and bolts, turning them into wood or cardboard.
- Extend the activity by making paper beads from the rolled paper triangles for a craft project.
Safety Precautions
- Supervise use of sharp objects if real screws or bolts are demonstrated.
- Ensure pencils or other rolling objects are used safely to avoid poking.
Questions to Consider
- How is a screw similar to a ramp? (It is an inclined plane wrapped around a rod.)
- Why is it easier to use a switchback trail than climb straight up a steep hill? (Because the incline is spread out, requiring less force at one time.)
- What advantages does wrapping the ramp around a rod provide? (It allows long ramps to fit into a small space and lets screws hold or lift materials more effectively.)