Converting Celsius to Fahrenheit and Why It Works

Date: 04/03/2004 at 20:54:04
From: Kittra
Subject: Temperature

What are the Fahrenheit and Celsius patterns that will help me 
predict Fahrenheit temperature based on the Celsius temperature?

Date: 04/03/2004 at 22:20:47
From: Doctor Peterson
Subject: Re: Temperature

Hi, Kittra.

I don't know exactly what "pattern" you are expected to see, 
especially at your age, but I can describe how the two are related.

The Fahrenheit and Calsius scales are just like using two different 
rulers to measure the same lengths, and also starting at two different 
places.  If I wanted to describe where I live, along Interstate 90, I 
might choose to say it in terms of the number of miles from Boston, 
and someone else might give me the number of kilometers from Albany.  
They will use different numbers to identify the same place.  To change 
one measurement to the other, you have to know how many miles there 
are in a kilometer, and how many kilometers or miles it is from Boston 
to Albany.

Here is a "road map" that shows all the information you need to figure 
out one kind of temperature measurement when you know the other:

      0    32                                          212 F
  <---+-----+-------------------------------------------+--->
            0                                          100 C
         freezing                                     boiling

Looking at this, you can see how many degrees F there are in 100 
degrees C; and how much you have to add because F starts at a 
different place.  It takes 180 degrees F (212-32) to cover the same 
"distance" as only 100 degrees C; so every time you go up 10 degrees 
C, you go up 18 degrees F.  Each degree Celsius is the same as 1.8 
degrees Fahrenheit.  So to convert a Celsius temperature to 
Fahrenheit, you have to multiply by 1.8 (or 9/5) to get the right size  
of a degree, and then add 32 to change the starting point.

If you have any further questions, feel free to write back.

- Doctor Peterson, The Math Forum
  http://mathforum.org/dr.math/