Why does the kettle get louder and louder as the water heats up, and then goes completely silent just as the water starts to boil (and before the whistling starts)?
I’ve noticed this recently, because my night shifts are slow enough that I can actually sit and watch the kettle boil. No paint drying, you see - gotta do something.
I know why it whistles - steam escaping that little opening. But the louder-and-louder-until-silence thing is driving me nuts. Help?
I believe it’s caused by cavitation. Tiny bubbles form in the water, however since the vapor pressure isn’t higher than the air pressure the bubbles collapse before they reach the surface. The sound you hear is the bubbles collapsing. As the temperature rises, more and more bubbles are formed and collapse, making it louder. However, when it reaches boiling, the bubbles reach the surface instead of collapsing, so the pot gets quieter.
Or (dang, searched AFTER typing that), in The Master’s own words.
(At least I know now why I know that fact.)
Dammit, and I searched, too.
Thanks, Turek.
NP, it was the highlight of lying in bed at 4am not being able to sleep. <sigh>
Well Turek, if its any consolation, you’ve helped me as well. I’ve boiled many tea kettles in my day and I’ve always wondered about this. You’ve done me a great service. Sleep well.