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Interesting problem ... basic engineering solution

gkenyon
So, today's engineering problem goes like this.


Someone in our family is dying their hair. The chemical (probably a Chromate-based hair dye) must be mixed with 180 ml of water at between 40 and 50 °C - if the temperature is too low, mixing is very difficult, too high and the compound breaks down, and perhaps you might not get the hair colour you need.


Simples ... except we have no thermometer.


How was this quick and easy to resolve?


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  • 0
    Agreed ... perhaps takes a lot of watching to get the point where the ice melts.


    If the engineer is me, the hair dye would have to travel back in time to be useful ... perhaps another project.


    Another bit of Engineering though - the test before mixing - "Feels warm" is just above body temperature, "feels hot, but doesn't burn" is probably less than 50 deg C.
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  • 0
    Agreed ... perhaps takes a lot of watching to get the point where the ice melts.


    If the engineer is me, the hair dye would have to travel back in time to be useful ... perhaps another project.


    Another bit of Engineering though - the test before mixing - "Feels warm" is just above body temperature, "feels hot, but doesn't burn" is probably less than 50 deg C.
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