Hold it in place or move it along. Screws do both jobs all day long.

something screwy going on

By Glen Phelan

Screw

Simple
Machines

Explorer magazine’s six‑part series

Before you read

Simple Machines

Explorer magazine’s six‑part series

lever
inclined plane
Wedge
screw

This edition

wheel and axle
pulley

Human Journey

Physical Science

Before you do the science activity at the end of this article, think about how you will record the results.