Boiling water in a paper cup.
By Barry Jeffrey, Apr 15 2015 07:12AM
Here’s a good exercise to help a group challenge their normal thinking and help them explore the concept of thinking outside the box.
Boiling water in a paper cup. At first thought, it sounds impossible, but let’s have a go.
First, fill the paper cup with water. No special preparation is required. The water doesn't have to coat the outside, and you don't have to expose only the wet parts of the cup to heat. Just fill a paper cup with water and start heating the cup from the outside with a blowtorch or something similar. After a short while, the water will boil vigorously inside the cup, but the paper cup itself, will not combust.
Why we can do this.
Paper burns at around 260 °C (500 °F) but water boils at a mere 100 °C (212 °F). This means that when the flames heat the paper to above 100 °C, the water nearby turns to vapor and steams away, leaving cooler water to take its place. So the boiling water can't get above 100 °C. Because the paper is relatively thin, the water keeps its temperature from climbing high enough to combust. It's only when the water on the other side of the paper entirely boils away that the paper cup will burn away.
It’s a simple exercise, but one that gets people thinking outside the box