A pyrotechnic party trick that involves grapes bursting into flame in a microwave has been explained by scientists.
The trick, popular at science fairs and on YouTube, is performed as follows: Cut a grape into two halves joined by a small piece of skin and place in a household microwave oven.
Switch on at full power and enjoy the spectacle as white hot fire erupts from the point where the two grape halves touch.
While many have sought to provide a scientific explanation behind the phenomenon, few have gotten it right – until now.
A new study conducted by a team of Canadian scientists shows how the phenomenon is triggered by charged molecules containing sodium and potassium.
Scientists used a combination of thermal imaging and computer simulations of electromagnetic fields to explain the physics behind why sparks are generated from microwaved grapes.
Experiments with water-based hydrogel beads and computer simulations revealed that the joining piece of skin does not play an important role, as was previously thought.