Celsius and Fahrenheit

Retrato de Anders Celsius (1701-1744) del artista Olof Arenius.
Portrait of Anders Celsius (1701 – 1744) by the artist Olof Arenius.

Some readers have been surprised that physics is being talked about in a section that, officially, appears in the section “Mathematics”; But we must not forget that it was precisely Galileo, the father of physics, who said that the book of nature is written in the language of mathematics. In other words: physics has science what it has mathematics, so moving between the two subjects is most natural (never better said), especially in a section called “The game of science.” So …

Can there be a low consumption electric stove? counts the levels of theft achieved by electricity rates). Well no, and for a very simple reason: if an electric motor or a light bulb does not have a performance of 100%, it is because part of the energy is lost in the form of heat; But when it comes to producing heat, there is no loss: 1 kilowatt-hour is equivalent to 860 kilocalories (how much water can we boil with 1 kWh?), and there is no way to increase this performance without violating the law of conservation of energy; and neither to decrease it, since energy ends up degrading into heat (which is not any degradation when what is sought is precisely to produce heat).


  • Energy conversion

In the case of bulbs, yes, of course, there are low-consumption ones, since, in traditional incandescent bulbs, which, as their name suggests, produce light by heating a tungsten filament until it turns white, great part of the energy is dedicated to overheating the filament and it becomes infrared, invisible to the human eye. That is why old light bulbs burn, if we touch them, within a few seconds of being lit, and that is why in many countries they are prohibited, since they represent a huge energy waste. LED and fluorescent lamps have about five to six times the efficiency.

Hot and cold

Electricity can be used for heating, and also for cooling: fans and refrigerators are there to prove it. But hadn’t we agreed that energy is converted, directly or indirectly, into heat?

Otherwise, let’s consider the following sentences :

“Turn off the fan, it’s very hot.”

“Get close to the refrigerator, it’s very cold.”

Are they mere nonsense or can they make any sense?

And from the nonsense phrases to the bream dialogue:

Two fishermen are crossing a lake in a rowboat. One of them asks about the temperature and the other, after consulting a thermometer, says a certain number of degrees.

“¿¿ Celsius or Fahrenheit? “, Asks the first.

” Doesn’t matter, “answers the second.

Is the answer acceptable? What if instead of fishermen they were lion hunters? What if they were bear hunters?

And, speaking of outrage, if someone who did not have matches wanted to burn a book by heating it in a frying pan, how many degrees Celsius would you have to heat it to? (Don’t try to do it at home.)

Let’s remember that on the Fahrenheit scale water freezes at 32 ° F and boils at 212 ° F, and you don’t need to remember, as everyone knows, that it freezes at 0 ° C and boils at 100 ° C. What should be pointed out, since many (including the media) do not take it for granted, is that it is not correct to speak of “degrees centigrade” (see in this regard, on these same pages, the interesting article by Dolores del Campo “ Is it true that degrees Celsius don’t exist? ”).

Carlo Frabetti is a writer and mathematician, member of the New York Academy of Sciences. He has published more than 50 popular science works for adults, children and young people , including ‘Damn physics’, ‘Damn math’ or ‘The great game’. He was a screenwriter for ‘The Crystal Ball’.

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