77 Simple and Complex Machines-Low

Simple and Complex Machines Written by Ned Jensen

Introduction How do you eat soup? Did you know that a spoon is a tool? A tool is a simple machine. A machine uses energy to help us do work. Machines that have only a few parts are called simple machines. Some machines are made of many simple machines. A bike is a complex machine. In this book, you will learn how machines make work easier.

Do You Know? Animals use tools, too! Apes use sticks to get ants. Sea otters use rocks to open clamshells. In science, work has a special meaning. It means making something move. To move something, you use force. If you push hard to move something, you use a lot of force. If you use a lot of force, you do a lot of work, If you push only a little to move something you use a little force. If you use a little force you do a little work. When you do work, you also move something over a distance. If you move something a short way, you do a little work. If you move something a long way, you do a lot of work.

Machines often help you move something (do work) using less force. But there is a trade-off. When you use less force, you have to move the thing farther. The total amount of work stays the same.

Types of Simple Machines These are the simple machines you will read about in this book.

Inclined Plane The ramp is a simple machine. It is also called an inclined plane. A ramp helps people move heavy objects up or down. Movers use ramps. It is easier to slide a box up an inclined plane than to lift a box straight up. Using a ramp takes less force. If you use a longer inclined plane to move a box up the same height, you need less force. But remember, you also have to push the box farther.