Electric Kettle

[jadyn]

My young daughter has asked me a question today that I can't answer.

We've got one of those new fangled jug type electric kettles that is illuminated blue inside when the water is cold but becomes illuminated red after the water has boiled. We've noticed that the fully sealed element in the bottom of the kettle has a stainless steel tube rising from it at the side that almost reaches the lid of the kettle. The tube is capped by a plastic T- shaped piece and wonder if this is something to do with the illumination or something to do with the kettle knocking itself off after boiling. We've not seen this tube in other kettles.

Is there a website out there that explains a bit more about this?



Thanks guys.

[ChuckFickens]

my guess is the tube has more to do with the water level indicator that is probably on the side of the kettle just next to the tube

Could be wrong though :)

[jadyn]

Thanks ChuckFickens but the only water level indicator in the kettle is engraved on a plastic panel built into the stainless steel body of the kettle. The tube is nowhere near it.

[buildersmate]

A very interesting question. Some years ago I was using the technology shown in the website below to sense temperatures on manufacturing processes.
http://solutions.3m.com/wps/portal/3M/en_US/Fo od_Industry/Home/Prod_Info/Products/Monitoring /Time-Temp_Indicate/
I'm pretty sure the answer for kettles is based on similar technology from 3m or someone else. It's basically a multilayer type that reflects light in different parts of the spectrum according to the temperature of the tape layer.