So this sent me down the wikipedia rabbit hole :D<p>One thing I never realised is how dramatically the viscosity of water changes with temperature. This is probably why you can recognise hot water from a cold water in a video.<p>Temperature (C) / Viscosity (mPa*s)<p>0.01 1.7911<p>10 1.3059<p>20 1.0016<p>25 0.89002<p>30 0.79722<p>40 0.65273<p>50 0.54652<p>60 0.46603<p>70 0.40355<p>80 0.35405<p>90 0.31417<p>99.606 0.28275
The author of this paper is Ed Purcell - <a href="https://en.wikipedia.org/wiki/Edward_Mills_Purcell" rel="nofollow">https://en.wikipedia.org/wiki/Edward_Mills_Purcell</a><p>If you studied physics in college, you may have used the textbook he wrote, Electricity & Magnetism.
Hmm, it looks like (TFA author) Purcell's "Back of the Envelope" AmJPhys column, paywalled for decades by AAPT, is currently available online.[1]<p>"a monthly feature [...] from January 1983 through July 1984. Three new "order-of-magnitude" problems were presented each month [...] there were 57 problems, the discussion of which fills something like 150 column-inches". Eg, the ratio of tide influence from Moon and Sun is 7/3, so what is the ratio of their mean density?<p>[1] <a href="https://www.aapt.org/Publications/AJP/Readers/back_of_the_envelope.cfm" rel="nofollow">https://www.aapt.org/Publications/AJP/Readers/back_of_the_en...</a>