Does water weight less when it's boiled?

01 November 2009

Question

Does water weigh less when it’s boiled? My kettle feels lighter when water is boiled than when it’s cold.

Answer

Well, Les, if your kettle is open at the top than it would have evaporated a bit of water so it may have lost weight purely through evaporation but if the kettle is a sealed unit then E=MC2 says, If you add energy to the kettle when it's hot, therefore, it should weigh slightly more than the water's hot than the water is cold.

Add a comment