Sometimes the obvious isn't obvious
In the lab today I was doing a routine chemical process, which runs at 65±5°C. I usually sit the beaker of liquid on a temperature controlled hotplate, and monitor the actual temperature using a digital thermometer connected to a thermocouple probe immersed in the liquid.

However, today I discovered that someone had broken my probe, which meant the thermometer was giving meaningless readings. I was somewhat annoyed at this, and even though I can usually stick my finger in a liquid and tell the temperature to within 5 degrees, given the noxious contents of this beaker I wasn't going to do that. And it's hardly scientific either.

I was now concerned about how I was going to measure the temperature, so I came back to my office, wondered if anyone else had a suitable probe I could borrow, or whether I could make one, and also looked on the web for replacement thermocouples from RS etc. Then the obvious answer hit me....

Why not use a mercury thermometer?

So I did. And it works perfectly. Doesn't even switch itself off after five minutes to save its battery.

Normal people would have thought of this instantly...
( K2k6 has a proper job these days, Wed 12 Mar 2008, 15:50, 2 replies)

out of curiosity
what reaction were you doing?
( willenium Fist bump for verification, Wed 12 Mar 2008, 16:16, closed)

I laughed.....
....when you said you broke your probe.
(JasperSinister is offering two tickets to the gun show, Wed 12 Mar 2008, 16:53, closed)