Especially in summer, you should be very careful about what you leave in your car. A water bottle should not be one of them.
Most of us have experienced it: you park your car, get out, and maybe leave a water bottle inside. What many people don't realize, however, is the potential danger that this everyday situation poses.
As an eye-opening demonstration by the Midwest City Fire Department in Oklahoma shows, an innocent water bottle – whether made of glass or plastic – can inadvertently start a fire if left out in hot weather.
Danger in hot weather in the car: water bottle becomes a convex lens
In the striking video, a firefighter demonstrates the hidden danger by taking a plastic water bottle and holding it over a sheet of paper in the bright sun.
Within a very short time, smoke forms and a burn hole begins to form in the paper. The physics behind it is simple but fascinating.
When the sun hits the water bottle at a certain angle, the bottle acts as a convex lens, similar to a magnifying glass. The sun's rays are focused by the water bottle, creating an intense focal point that can generate enough heat to ignite materials like paper or even car seats.
Not every water bottle poses a risk
This process can occur with almost any transparent bottle and transparent liquid, but water bottles are particularly common in cars. The fact that many people unknowingly leave their water bottles in cars makes this danger even more acute.
It is important to stress that not every water bottle left in a car will necessarily start a fire. The conditions have to be right: the sun has to hit it at a certain angle, and there has to be a flammable material under or near the focal point. Nevertheless, it is a danger that should be taken seriously.
The Midwest City Fire Department is using this demonstration to raise awareness of this potential danger. The simple act of removing a water bottle from a car, especially in sunny weather, could prevent unwanted fires and save lives.
Source: YouTube/Audacy
By Philipp Rall