But there’s a small detail about clear, water-filled bottles and direct sunlight that is worth knowing.
Under the right conditions, a transparent bottle filled with water can act somewhat like a lens, bending and concentrating sunlight onto a relatively small area. That concentrated light can potentially heat the surface it lands on.
This doesn’t mean every bottle left in every car is suddenly going to start a fire.
The risk depends on several factors, including the shape of the bottle, how full it is, the angle of the sun, where the bottle is sitting, and what the concentrated light lands on.
