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Why Does the Road Look Wet When It’s Hot Out?

If you’ve ever driven in the blazing Pennsylvania summer sun, you may have noticed a unique phenomenon—a seemingly “wet” patch of road that disappears as you drive closer to it. You might have even slowed down or prepared yourself for hydroplaning if the illusion was particularly strong. Obviously, the road isn’t actually wet—but what causes us to see the road this way on days when it’s hot out?

Light moves at different speeds depending on the density of what it’s traveling through. If light is traveling through a medium with low density (like air), it will move much more quickly than if it was moving through a higher-density medium like water. When light moves from an area of low density to one of high density, it “refracts,” or moves in a U-shaped pattern instead of a straight line.

Hot air is less dense than warm air or cold air—if you’ve ever been in your attic during the summer, you’ve probably noticed that all of the hot air in your home has risen to the top layer of your house due to its low density. As light travels from the sun to the blacktop of the road, the blacktop warms up, heating the air above it. Once the air on the ground has been warmed up, additional light waves bend and twist as they hit the ground. However, your brain can’t “see” the bending and twisting light patterns, and instead interprets the light’s point of origin due to the refraction. The final image is of the water particles in the sky, which our brain interprets as a puddle on the road.

This phenomenon is called a “mirage.” Sand shows the same refraction phenomena as paved roads—which has caused many a stranded desert traveler to hallucinate a “pool” of water in the desert, much like drivers do on the road.

Remaining alert and vigilant is especially important during the summer season. Dehydration and mirages can cause even the most careful drivers to get into an accident, and cause you to need collision or dent repair in Bensalem, PA. When you drive this summer, remember to stay hydrated and well-rested, avoid distractions like cell phones and food, and call Peruzzi Collision Center for collision and dent repair near Levittown, PA to make sure your vehicle is safe and road-ready. To learn more about dent repair or safe driving habits, give our team a call today at 215-375-7929!