The need to convert Fahrenheit to Celsius can pop up in odd times and places. For example, there was a story about a boy who had to stay home from school with a cold. After the doctor left the boy began acting very sad and depressed.
That evening the boy’s father observed him making a list of his favorite possessions. The father asked what he was doing and he said he was deciding who he wanted to leave his stuff to after he died. His father asked him why he was thinking about dying and he said he heard the doctor say his temperature was 100 degrees. His father said such a temperature is not unusual when you have a cold. And the boy said that a boy at his old school had died when his temperature was only 42 degrees.
Dad explained that in the old country they measured temperatures in Celsius degrees but in America they use Fahrenheit. Since this is a story that took place back when doctors still made house calls the boy could not just go on the Internet and find a temperature conversion calculator. So his dad probably taught him how to convert Fahrenheit to Celsius degrees. Although if it was that long ago they probably would have said Centigrade instead of Celsius.
The first thing this father probably told his son is that water freezes at 32 degrees F. And water freezes at 0 degrees C. That is obviously 32 degrees difference. If you subtract 32 degrees from the Fahrenheit temperature you get the Celsius temperature. Unfortunately that only works at the freezing temperature of water but if you can remember that you are half way to being able to convert any temperature. Remember the number 32.
Now suppose like the boy in the story you had a temperature of 100 degrees and you wanted to know how much that is in Celsius. You would start by subtracting 32 from one hundred. That’s sixty eight. If your temperature was 68 degrees Celsius you would be very very dead. This is a hint that your calculation is not finished.
What you must do next is multiply your 68 by 5/9. If you are as young as the boy in the story and haven’t yet learned to multiply fractions it’s all right. Just multiply by five and then divide by nine. Or if you are better with decimals than fractions, divide by 1.8.
The answer you get will be thirty seven point seven followed by a long row of sevens and then an eight. It doesn’t matter much how many numbers come after the decimal point unless you are taking a test. You can see that the number is slightly higher than thirty seven which is normal human body temperature.
If your temperature was 37 Celsius and you wanted to know what that is in Fahrenheit you would follow the same steps only backwards and upside down. You multiply thirty seven by 9/5 or you multiply by nine and divide by five. Or you multiply by 1.8. That gives you 66.6. This temperature is not any healthier in Fahrenheit than it is in Celsius. Don’t forget to add that 32 degrees that you took away from Fahrenheit to get Celsius. When you are going the other way you have to add it. 32 added to 66.6 is 98.6, normal temperature for a healthy human body.