The Whistle

A whistle is a small tool that makes a loud sound. You blow air into it, and it makes a high, clear note. Whistles can be heard from far away, even in noisy places. People use them for sports, safety, and music.

How Whistles Work

Inside most whistles is a tiny ball called a pea. When you blow into the whistle, the air makes the pea jump around fast. This makes the air wiggle and creates the loud sound. Some whistles do not have a pea and use air alone. The shape of the whistle decides how high or low the sound is.

Where Whistles Are Used

Referees in sports use whistles to stop and start games. Police officers blow whistles to get people's attention. Trains used to have giant steam whistles that you could hear for miles. Lifeguards carry whistles to warn swimmers of danger. Some whistles are even tiny enough to wear on a necklace for safety.

Fun Facts

• Dog whistles make sounds so high that people cannot hear them, but dogs can.
• A man named Joseph Hudson invented the pea whistle in 1884.
• Some birds can whistle songs that sound like people.

Did You Know?

Soccer referees have been using whistles since 1878, long before most modern sports started.