Will a Kettle Full Of Alcohol Stay On Forever?

Summary by Krater

Steve Mould investigates whether a kettle full of alcohol will automatically shut off when it boils, exploring the mechanics of bimetallic strips and vapour pressure in electric kettles.

From the video

Answers: Does a kettle full of alcohol turn itself off when it boils?

• Alcohol boiling point in electric kettles
• Bimetallic strip mechanism in kettles
• Vapour pressure and boiling point
• Heat transfer and sink properties

What it concludes

• A kettle full of ethanol does not turn off automatically because its boiling point is lower than the trigger temperature of the bimetallic strip.
• When a water-ethanol mixture boils, the vapour is richer in ethanol, causing the liquid concentration of ethanol to decrease and the boiling point to rise toward 100 C.
• A kettle with a bimetallic strip in the base and a tube routing steam down from the lid will trigger the switch at temperatures lower than water's boiling point because boiling liquid produces vapour that increases internal pressure across the bimetallic strip.