Why Do Fly Swatters Work?

If you’ve ever tried to swat a fly with your hand or with a book, you’ve probably found that the pesty insect takes off before you can strike it.

how do fly swatters work

Flies have sensory hairs over their bodies, and these hairs can feel slight changes in air pressure. A moving hand pushes the air down on the fly, and the insect’s hairs pick up the change in air pressure and alert it to take off.

What makes a fly swatter work is not its shape or its strength, but the holes in it. When you swing a fly swatter, air passes through the holes, and not enough air is pressed downward on the fly to alert it.