Colored Arcs

PIRA: 6J10.30

Overview

The arc-size illusion is a fascinating visual trick where identical arcs appear different in size due to their positioning. This occurs because the human brain compares curved edges, altering the perceived dimensions. This illusion demonstrates how context influences our perception of size. Shorter arcs, placed next to longer ones, look flatter or smaller despite being identical in curvature.

Materials

At least two different colors of plastic arcs

Setup Instructions

1. Spread out the preferred number of arc segments.
2. Lay them down on a flat surface.
3. Ensure the colored arcs are visible 

How to Perform the Demonstration

1. Show the arcs separately to participants and confirm they are identical.
2. Place them together as described and ask participants which one looks bigger.
3. Encourage participants to measure both arcs to prove they are the same size.
4. Discuss the brain's tendency to compare curved edges and how context influences perception.

Safety

• Be cautious of the edges of the plastic pieces under the right circumstances they can cut peoples hands.