Interference Pattern

Overlay the cards to create unexpected patterns.

How it Works

When similar patterns are layed over each other, other shapes start to become visible. These are called moiré patterns.

Things to Try or Ask Around the Exhibit

• Try moving the cards at different speeds and in different ways. Do you see the moiré patterns change?
• Do the patterns move differently when you move the cards left-to-right, as opposed to up-and-down?

Background

Moiré patterns arise because of differences between two superposed patterns, and while they can be visually impressive they are not always desirable.

Finding the Science in Your World

Moiré patterns appear when looking through multiple fly screens, viewing particular patterned clothing on televisions, and are used to prevent photocopying of certain protected documents.