My birthday cake had candles on it that I couldn’t blow out. How do these work?
• The short answer is that they have magnesium incorporated into the wick.
For a flame to exist, it needs oxygen, fuel and enough heat to keep combustion going once it starts. These requirements are sometimes represented graphically as the three sides of a “fire triangle”.
When you blow out an ordinary candle, you extinguish the flame by removing heat. You can still see the fuel – the wax smoke, often paraffin vapour, coming from the wick – but the ember in the wick does…
