CHAPTER 9
TIME AND TEMPERATURE
The 12-hour clock with a.m. and p.m. times could be unfamiliar to many ESOL learners as the 24-hour system is preferred in other countries
In English and in other languages like German, there has been a contraction of the number or words used to describe times, which can be confusing (i.e. in English half past eight can be shortened to half eight)
Time calculations are complex because the base is 60 for seconds and minutes, rather than the normal 10. This means that calculators must be used with caution
In the UK, learners may hear both Celsius or centigrade and Fahrenheit temperatures used.
Conversions between centigrade and Fahrenheit are required by some curricula- BODMAS or BIDMAS must be used
Introduction
As often happens in the UK we have two systems for both time and temperature, where really one would do. Most of the rest of Europe uses just one system for each, namely 24-hour clocks and Celsius for temperature, but the USA is different. It seems that as a country, the UK is never entirely sure who it wants to be best friends with, Europe or the USA, so both systems are maintained, regardless of any confusion they might cause.
Time
So, when we look at time it is more complex than it might seem and can be very confusing to ESOL learners. Most cultures use both the analogue (a round clockface numbered 1 to 12) and digital ( a number display, such as 9.30) systems for telling time, but not all cultures and countries use the 12- and 24-hour clock systems, preferring to stick to the 24-hour clock to avoid confusion. Spanish students are, among others, perplexed by the 12-hour clock, which means that in the UK we have to say a.m. and p.m. to explain whether we mean morning (a.m.) or any time from 12 noon (midday) (p.m.). If we did not use a.m. or p.m., and I asked you to meet me at 9.30, there would be no way of telling whether this was morning or evening. Whereas in Madrid, if 9.30 was specified it would definitely be morning, because if it was not, 21.30 would have been specified.
Timetables for buses and trains in the UK always use the 24-hour system, so UK residents will need to understand it.
In addition, not all languages use the same ways of describing the time in relation to the hours, for instance in French the literal translation for 7.45 is not a quarter to eight, but eight less a quarter, and in German it is a quarter before eight. Confusingly in German 8.30 is ‘halb neun’, or half (to) nine, because the ‘to’ has been dropped. However, in English we would say that 8.30 is half eight, having dropped the ‘past’ out of ‘half past eight’.
In the UK we seem to say the time differently if reading from analogue as opposed to digital clocks, for instance ‘2.55’ can be heard if the speaker is reading from a digital watch, but if using an analogue watch face, we are much more likely to hear ‘five to three’. ESOL learners will need to be taught all the different ways that time could be spoken. This topic will come up in ESOL lessons and examinations as well as in mathematics examinations, although in the latter time calculations are more likely.
Time calculations
In my experience many learners find the performance of time calculations challenging. The reason for this seems to be that time is not in base 10, as is our normal counting system, but in base 60 for seconds in a minute, and minutes in an hour. If it is hours in a day, the base is now 24, days in a week is 7, etc. Great care has to be taken if performing time calculations of a calculator for this reason.
Planning a day to ensure that you make an appointment on time is an important life skill, and this skill is present in examination papers with such questions as:
‘Carl has an appointment in London. It takes 2 hours to travel by train to London, and 15 minutes at each end of the journey to walk both from home and to the appointment. If the appointment time is 10.35, what time must Carl leave home?’
Travel across time zones would seem to be a topic that could come up in a Geography exam paper, but may be of interest to everyone, if they contact people in other countries, or travel for business or pleasure.
Temperature
Temperature also uses two systems, namely Celsius, also known as Centigrade, and Fahrenheit. Fahrenheit was used in UK weather forecasts until the 1970s, and it can still be heard occasionally in weather forecasts today. Celsius, which was invented in the 1700s, is a Swedish system which has been used increasingly in the UK over the last 50 years or so. Celsius is easy to remember because it is based on the boiling and freezing points of water. Both Celsius and Fahrenheit are measured in degrees (º). Water boils at 100ºC and freezes at 0ºC. In the Fahrenheit system, which was invented in Germany at a very similar time to Celsius, water freezes at 32ºF and boils at 212ºF.
Many of the older generation in the UK still use the Fahrenheit system, and it has been a popular topic on exam papers for conversions. Conversions can be found at Level 2 of the FS maths curriculum, and on maths and science curricula and GCSE papers. A formula will always be given for these conversions but using it effectively does require knowledge of BODMAS or BIDMAS, which is the order that Maths calculations must be done in, unless you are told otherwise. I have re-included the section on BODMAS or BIDMAS below in case it is needed.
A formula for the conversion of temperature may look like this: Cº = (Fº – 32 )5/9. To convert 77ºF to centigrade, the order of operations is: 1) Cº = (77-32) 5/9; 2) 45 x 5, and ÷ by 9; with a mix of multiplication and division the order does not matter, so 3) 45 ÷ 9 = 5, and 5 x 5 =25. The final answer is that 77ºF is the same as 25ºC.
As previously mentioned, beware of the tempertaure calculations that lead to a minus or negative number!
BODMAS or BIDMAS
The abbreviations of the words contained in the short form above informs everyone on the order that calculations must be done in for our number system to work. ESOL learners may have their own version of BODMAS or BIDMAS using their first language, and it could be worth displaying all the different versions on a poster in the classroom, firstly as a memory aid, but also to show that maths skills in the first languages are acknowledged and valued.
‘B’ stands for brackets (like this)
‘O’ stands for operation of powers, such as when we square or cube a number, such as r squared, or when we find the square root of a number. / ‘I’ stands for indices, which is the posh name for powers or roots (Examples include: 3², 5³ or √25)
‘D’ stands for division
‘M’ stands for multiply
‘A’ is for addition
‘S’ is for subtraction
Thus, using the correct order of calculations, 27 + 0.4 x 3 would be 1) 0.4 x 3 = 1.2, then 2) add 27 to the answer, so = 28.2.
If I don’t use BODMAS I would get 27.4 x 3 = 82.2; this is the wrong answer and it is very different, though in this case interestingly the numbers are transposed, i.e. the 2 and the 8 have swapped position.
JMS 2026