[Note: There is a poll at the end of this blog. Please participate!]
To me, the most difficult part of the using the metric system day-to-day is getting used to the Celsius measure of temperature.
I changed the weather app on my phone more than a year ago so it’s much easier for me to use Celsius now, especially when you consider that 0° C is freezing. I know what freezing is, regardless of what system is employed. At the other end, 100° C is boiling instead of our 212° Fahrenheit. Since it’s slightly imprecise (compared to what we use now), some countries compensate by using decimal measures for temperature so it’s sometimes reported as 18.3° C, for example. (In Fahrenheit, 18° C could be anywhere between 64.4° to 66°. Okay granted, now that I look at that it looks pretty silly–the middle 60s are still the middle 60s. The decimal point doesn’t really help me decide how many clothes I should wear when I go outside…)
During my research for this documentary I found several rhymes to help people adjust to the “new” (at the time) metric measures. I used one of them during my previous presentation at the MidSchool Math conference last year but had to apologize since it hit me as a little clunky. I told my audience that I hadn’t had time to write something better.
Given that I’m presenting next month at the same conference (slightly different topic than last year) I decided I needed to do what I said I’d do and try to come with something I thought worked a little bit better.
The poem I presented last year:
This bothered me a little since the construction is not parallel…that third line throws me off and seems out of sync (not written by a poetry major perhaps?)
On the U.S. Metric Association pages:
A bit better but I thought I’d take a stab at it as well. Here’s what I came up with (original to the best of my knowledge):
At 30 it’s hot
At 20 it’s pleasing
At 10 it’s cold
And 0 it’s freezing
I think it works because “pleasing” and “freezing” rhymes, “hot” and “cold” in the second and third lines shows a decreasing sense of temperature (as do the rest of the rhymes I came across).
Hey, you tell me. When the U.S. decides to convert to the metric system, which poem is the easiest to remember for you? I’ll leave the poll open a couple of weeks and will use the most popular version as I move forward with my project.
Thanks for your participation!
Linda
More Than A Mile Behind: America and the Metric System 
While degrees Celsius may be somewhat less precise, I think whole numbers are perfectly adequate for weather reporting purposes. If you look at a typical mercury thermometer, each tick mark is 1 °C. That’s all the resolution you really need. The decimal point adds no meaningful information for the public.
It is a common misconception that Fahrenheit is more accurate due to greater resolution of numbers. Actually in practice, this is very untrue. Fahrenheit has greater resolution, but not greater precision. Temperature is not homogenous throughout a medium. There are hot spots and cold spots that can vary a degree or two. When we want to know the temperature of a space, we want to know the average, not the specific temperature at a single point.
The Celsius scale is actually more precise for this . It gives us the “average” for the space in whole numbers. Fahrenheit is too fine and in fact measures a lot of what would be considered thermal noise and not actual temperature. The supposed extra resolution of Fahrenheit doesn’t really provide you with useful information on what your body feels.
People in metric countries who work daily in degrees Celsius are more apt to be able to feel the Celsius temperature without the use of a thermometer, whereas the majority of Fahrenheit users need a thermometer to ascertain the approximate temperature. The human body can only detect a difference of one Celsius degree.
Maybe in some fine scientific work, either theoretical or in a laboratory, decimal parts of a degree serve a purpose, and I would think for the use of the kelvin unit only. The Celsius scale was “designed” for common use by the average citizen to know the temperature of his environment and never need be expressed to less than whole numbers.
I live in a thoroughly metric country, and the only time you see a decimal point attached to the temperature is when they are reporting historical averages. Here’s the forecast for my home town, Melbourne, Australia: http://www.bom.gov.au/vic/forecasts/melbourne.shtml All the temperatures are whole numbers with no decimal point.
People can’t really judge the temperature to within one degree (of either scale) and the outside temperature is dependent on wind, shade, and other factors. (Are you standing in a baking hot concrete parking lot or a cool grassy park?)
As you said, you really only need to know how many layers of clothing to put on.
Even historical averages can be rounded to a single whole number. The temperatures one takes for a city are usually from a central location, such as an airport, and the temperatures taken would only be accurate at the exact location they are taken.
I switched my phone weather app, laptop weather app, and body thermometer to Celsius a little over a year ago and I can think in Celsius no problem. It’s funny though because now whenever I hear Fahrenheit temperatures my mind panics for a minute at the large numbers i.e.: 57 ºF is 14 ºC other than that I’ve let go of Fahrenheit. I saw a video posted by a professor at UCSB (University of Santa Barbara) in California, and research statistics were given in degrees Celsius but then when referring to hot temperatures the professor said “A hundred degree day in Texas” rather than saying “A 30 plus degree day in Texas”.
It’s easy to describe outside temperatures in a friendly manner in Celsius like in Fahrenheit, if it’s going to be a cold day you can still say “Single digit temperatures”, if it’s a cool to warm day you can say “Teen temperatures”, and warm to hot day you can refer to the bigger numbers like “It’ll be a warm day today with temperatures in the mid to high 20s, or today it’ll be scorching hot with temperatures ranging from the mid 30s up to the 40s”.
While I see that one could find a value in such rhymes, I find it unnecessary, and even distracting. I live in Texas. By no means a bastion of metric users. I’ve set my phone weather app to Celsius. I then just use it. It has not taken me long to get a feel of what temperatures feel like. Each season (summer, winter) I had a little bit of time to get accustomed to what to expect with the given C reading, but I didn’t need a rhyme or conversion. Occasionally, I find I have to convert for friends and family who just don’t get it, but for my own uses it has only been a little over a year and I have adjusted easily. In fact, I find I prefer it. Where I have temperature gauges that don’t offer a choice, like in my car, I find I now want to convert from F to C to make more sense of it. (I really don’t think Americans would have as tough of a time adjusting as so many claim.)
I print on the rulers and pens and pencils I distribute the Celsius poem:
30 is hot,
20 is nice.
10 wear a coat,
0 is ice,
It flows better that way. Also, I have about 20 other metric poems I have written, including the Speed of Light:
Five zeros after three,
That’s KIL-o-met=ers, see?
Each second, day or night,
That is the speed of light.
Let me start off by saying that I am a PhD Chemist and I am equally familiar with both the Celsius and Fahrenheit temperature scales. The Celsius has no particular advantage in scientific work. True scientific calculations are almost always done in Rankine and Kelvin. These scales have absolute zero as their zero point rather than some arbitrary zero point that leads to negative temperatures. As a matter of fact Celsius’s only advantage Is that it is used by most of the World. Then Fahrenheit scale is a much more “human” scale. Zero Fahrenheit is the lowest temperature most people are commonly exposed too and the same is true of 100 Fahrenheit is about the upper end of normal exposure. I know on Earth you can find much lower and higher temperatures than these. But, they are much less common. You don’t need some “Rhyme” to remember this. The accuracy and precision of temperature measurement has nothing to do with which scale you are using. I vote for a human temperature scale rather than the “Scientific” scale.
Shortening the rhyme helps and easier for children to remember – 30 is hot – 20 is pleasing – 10 is cold – 0 is freezing. Also changing “put on a coat” to “10 needs a coat” seems to flow out easier when speaking. Just a few thoughts from an early childhood educator. Thank you
0 is freezing, 10 is not. 20 is freezing, 30 is hot. 40 is frying. 50 is dying.
This is the children’s rhyme. Not sure why you are going backwards and not rhyming.
20 is freezing???
The rhyme I learned is “30 is hot, 20 is nice, 10 is not, 0 is ice…”
not [implied not nice]… that’s where the rhyme works
Cool article. Cool rhymes. In Australia there was a PR campaign in 1974: frosty fives, tingling tens, temperate twenties, thirsty thirties, fiery forties.
I find it interesting that we don’t need a rhyme to understand the F scale.
If you’re telling me that you don’t need something to remind you of something you already know, I couldn’t agree more. However, for people who are not familiar with the metric system, they find the rhyme very helpful. After much searching, I was able to find a music video to help people learn the Fahrenheit scale but it is much longer than than the four-line poem for Celsius and only addresses three temperatures. https://www.youtube.com/watch?v=Vk6rP_4wpvk
It includes the lines:
Check out the temperature, 32 degrees, liquid turns to solid and water will freeze
Check out the temperature, two hundred and twelve
Water gets hot and it might make you yell,
because it’s boiling
But somewhere in the middle is 68,
room temperature feels really great
The bottom line: Using rhymes helps us remember things that we don’t already know.
Florida version of the poem:
At 30 it’s nice.
At 20 it’s chilly.
At 10 it’s hypothermia.
At 0 you’re dead.
The end 🙂
30 is hot
20 is not
10 is not pleasing
0 is freezing
I taught this many years ago with a minor difference. 30 is hot
20 is nice
10 is chilly
0 is ice
What’s boiling water if you please?
100 Celsius degrees.