The sound of a boiling kettle is one of the most recognizable sounds in the kitchen. But why do kettles make noise? The main reason is because of two vibrating parts: the heating element and the water inside.
When an electric current flows through a metal heating element, it rapidly heats up and expands due to thermal expansion. This causes it to vibrate, creating a humming or buzzing sound that can be heard when you turn on your kettle.
At the same time, as water boils inside the kettle, bubbles form on the bottom of the kettle and rise to the surface. These tiny bubbles create mini-explosions as they reach their boiling point, causing them to break apart in a process called cavitation. This cavitation also creates vibrations that can be heard as loud rumbling noises coming from your kettle.
Kettles are designed with special filters that reduce these noises by trapping some bubbles before they reach their boiling point and preventing too much vibration from occurring within your appliance. Not all kettles come equipped with these filters, so if yours doesn’t have one then you may hear more noise coming from it than others do.
So there you have it – now you know why kettles make noise!