kubofal

Well, it could be helpful to find out if plastic kettles make that sound too. But anyway, I don't think there could become necessary difference in temperatures. Bottom of the kettle is still heated by element and in upper part of the kettle is boiling water. Difference between temperatures of outer and inner parts is also out because still kettle without pouring doesn't make that sound.

Hi! Thank you for replying. I am pretty sure it is not. There is only a heat activated switch for announcing boiling water. You can hear it in the begging of the videos.

Hi! Thanks for your reply. I looked at a bottom of the kettle. It is really robust and flat, no signs of oil canning. I am including a picture of the bottom of the kettle: http://imgur.com/gallery/7C55dUP/new Thanks for reply! I did experiment where i did not righ kettle so water did not met back with the hot element. Here it is: Also thank you for replying! There is no limescale on the bottom. Picture of the bottom of the kettle: http://imgur.com/gallery/7C55dUP/new

When I rather quickly poured water from a kettle and than I wanted to put it back onto it's stand I heard a short, squeaky sound. I recorded that phenomenon and thought about hypothesis. I was wondering if you could comment on my hypothesis and help me explain this sound. Thank you! Here is my hypothesis: http://postimg.org/image/fcf89vw8v/ Here is recorded phenomenon :

WOW. Thank you!! That's a lot of different ones indeed.

Yes. Hypothetically. I was just wondering if there is a reliable number of amino acids we discovered.

Out of curiosity.

To my knowledge there are 23 proteinogenic amino acids. From which 21 are used in eukaryotic organisms. From which 20 are coded by DNA. That's fine. But how many non-proteinogenic amino acids do we know, both natural and synthetic? I have googled inconvenient range of numbers (from 250 to 1500). Write down, if you will, also a source of your answer. Thank you.