Saturday, November 20, 2010

Order Pairs in Real Life

     Many times when I teach a topic in math I notice that students understand how to do a problem, but have no idea why or how this relates to anything.  Just ask any trigonometry student what trigonometry means and you might be surprised at the answer.  I was explaining to a group of algebra I students the topic of order pairs which would lead to linear equations.  Most of the students knew how to check to see if an order pair is a solution to a linear equation, but had no idea that a linear equation relates two values and an order pair happens when the two values makes a true statement.  I decided to use the formula that converts Celsius to Fahrenheit to use as an example how a linear equation works.  Students usually do not recognize that the formula is a linear and would graph into a line.  I asked them if they know the formula and explain to them which variable is the independent and which variable is the dependent.   Most of the students understood that it does not matter which value you use for Celsius, but the value you solve for in Fahrenheit depends on which value is used for Celsius.  The interesting part was when I asked the students to come up with order pairs that would be solutions for the formula.  I wondered if they would use the easy pair, which are the freezing point and the boiling point of water. (0,32) and (100, 212) shows two relationships that work for the equation.  Many of the students, after they were told, understood how and why this works.  What is nice about the formula is that it is in slope intercept form.  Where 9/5 is the slope and 32 is the y-intercept.  In a couple of weeks we will be working with the slope intercept form and I will use this formula to show how the slope works and how it can be use to calculate the next order pair. 

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