Our school correspondent, has written in with the following comment on the Andronov Temperature scale. If you want to see the previous articles on the subject they are here: Let me take your temperature on this and Temperature rising.
A little learning is a dangerous thing or so it is said. So as a pedant I would first like to point out that temperatures are measured in degree fahrenheit, degree celsius and kelvin noting that the names are started with a lower case letter to avoid confusion with the surnames of the scientists. Also a redefinition of the triple point of water means that the boiling point of water is no longer 373.15 K!And so to a useful “scale” or rather a more practical conversion between celsius (the unit I use in my capacity as a teacher) and fahrenheit (my preferred unit in relation to the weather). I claim no originality for this rather state what I heard and then make a further observation. Instead of playing around with ±32 and 5/9 or 9/5 a reasonably accurate, and hence perfectly acceptable, formula is “take thirty from the fahrenheit temperature and divide the answer by two” as shown in the table below:
t / °C |
t / °F |
t / ° |
error |
-20 |
-4.0 |
-17.0 |
-3.0 |
-18 |
-0.4 |
-15.2 |
-2.8 |
-16 |
3.2 |
-13.4 |
-2.6 |
-14 |
6.8 |
-11.6 |
-2.4 |
-12 |
10.4 |
-9.8 |
-2.2 |
-10 |
14.0 |
-8.0 |
-2.0 |
-8 |
17.6 |
-6.2 |
-1.8 |
-6 |
21.2 |
-4.4 |
-1.6 |
-4 |
24.8 |
-2.6 |
-1.4 |
-2 |
28.4 |
-0.8 |
-1.2 |
0 |
32.0 |
1.0 |
-1.0 |
2 |
35.6 |
2.8 |
-0.8 |
4 |
39.2 |
4.6 |
-0.6 |
6 |
42.8 |
6.4 |
-0.4 |
8 |
46.4 |
8.2 |
-0.2 |
10 |
50.0 |
10.0 |
0.0 |
12 |
53.6 |
11.8 |
0.2 |
14 |
57.2 |
13.6 |
0.4 |
16 |
60.8 |
15.4 |
0.6 |
18 |
64.4 |
17.2 |
0.8 |
20 |
68.0 |
19.0 |
1.0 |
22 |
71.6 |
20.8 |
1.2 |
24 |
75.2 |
22.6 |
1.4 |
26 |
78.8 |
24.4 |
1.6 |
28 |
82.4 |
26.2 |
1.8 |
30 |
86.0 |
28.0 |
2.0 |
32 |
89.6 |
29.8 |
2.2 |
34 |
93.2 |
31.6 |
2.4 |
36 |
96.8 |
33.4 |
2.6 |
38 |
100.4 |
35.2 |
2.8 |
Perfectly adequate (±1° most of the time) for those of us who live in England. Our friends in hotter or cooler climates might consider whether a tweak to the constant “thirty” is worth it.