What is a Simple Machine — Passage and Quiz

A machine is a tool that makes work easier. Simple machines change the direction or amount of force needed to do work. Six types of simple machines are the wedge, wheel and axle, lever, inclined plane, screw and pulley. Wedges concentrate force on a small point to split or lift objects. Wheels with attached axles reduce friction to roll heavy loads more easily. Levers use a fixed point called a fulcrum to change direction and speed up movement. Inclined planes require less effort to slowly raise objects to different heights. Screws are inclined planes wrapped around structures to hold objects together or lift materials up. Pulleys use ropes and wheels to reduce the amount of force needed by distributing weight. Understanding these simple machines helps explain how many complex modern tools and vehicles work.