How hot is it, beneath a sleeping cat?
Last November, we bought a new weather station. It's a clever little device which shows the humidity, pressure, indoors and outdoors temperature, and the date and time.
The time is synchronised to a radio time signal so it is always correct. The outdoors temperature is measured by a sensor which sends its readings to the display via a wireless link.
On Wednesday, my wife noticed that the sensor was giving an anomalously high reading first thing in the morning. It was showing room temperature, about 10°C (18°F) higher than outdoors, and it remained at the same reading throughout the morning, despite bright sunshine.
Oh darn, we thought. The sensor is faulty. We're both scientists, so we decided to test it. We put it in the refrigerator. The display remained at 20°C (68°F). We stuck it under the cat. It still showed 20°C.
Then we remembered that our neighbour has a similar weather station, and our display can pick up the signal from his outdoor sensor. We pushed a couple of buttons on the display and saw a reading of 33°C (91°F). That's the temperature under a sleeping cat, in case you ever need to know.
I took a look at our neighbours front porch, and saw that his sensor was no longer there. Eureka! The 20°C reading was clearly from his sensor, but inside his house.
Well, at least I now know how hot it is beneath a sleeping cat. And so do you, if you've read this far.