How Windshield Wipers Clear the Glass

Plip, plop, splash! Raindrops fall fast on the front glass of a car. This big front window is called a windshield. When it is covered in water, the world outside looks blurry. A driver needs clear glass to see the road, other cars, and people walking by.

With a quick click of a switch, the windshield wipers wake up. In many modern cars, a small electric motor hides under the hood. While not every wiper system is built the exact same way, this little motor often does the work. It turns and pushes metal rods. Those rods make the wiper arms swing back and forth across the glass.

Each metal wiper arm holds a long, flat strip of rubber. This part is called the wiper blade. The arm presses the soft rubber edge tightly against the wet window. Even though a windshield looks flat, it curves a little bit. The flexible blade bends so it can touch the glass all the way across.

Swish, swoosh! As the arm moves, the rubber blade slides over the raindrops. The rubber does not soak up the water like a sponge or a paper towel. Instead, it acts like a tiny broom or a snowplow. Its smooth edge scrapes the drops together and pushes the water off to the sides of the glass.