“The sunlight will come through, when it’s filled with liquid, and act as a magnifying glass as you would with regular optics,” said David Richardson with the Midwest Fire Department.
And this is where the risk comes in.
“It uses the liquid and the clear material to develop a focused beam and sure enough, it can actually cause a fire, a combustion,” said Richardson.
In a test at the Midwest City Fire Department, sunlight magnified through a bottle of water reached 250 degrees.
The extra heat can focus on a car’s interior materials, such as fabrics seats or mats, and potentially set them on fire.
Officials recommend keeping bottles of water out of your vehicle when not in use.