Monday, July 29, 2013

The Demise of the Teeter-Totter - and Its Implications for Algebra

Years ago, I was teaching in an elementary school computer lab. There was a software program I was using, where the students were supposed to balance bags of gold. On one side of the balance was a bag, for example, weighing 7 pounds, and they had to balance it with a combination of two or three other bags, e.g., 2 and 5, 3 and 4, or 1, 2, and 4. I was AMAZED and discouraged that so many of the students found this difficult. You see, years before that, teeter totters had been removed from many public playgrounds, because of insurance mandates. Many kids just didn't and don't know how balances work. This has big implications for mathematics and equation solving.

A few years later, I was substitute teaching in a 5th grade and the lesson was on balancing equations.  Again, I observed that the students simply didn't understand how balances worked.  They could not predict what would happen if something heavy was added to one side of an equation that was balanced.  No wonder so many of them are lost in beginning algebra.  

I am not sure we can bring back teeter-totters, but we can certainly bring back playing with balances in the younger grades.  Get the equipment out and let kids play with it.  

Tuesday, July 16, 2013

Temperature in Celsius

I have long thought that the United States should go metric, because it is a much more sensible system of measurement.  The metric system for lengths seems simple and easily understood.   A meter is quite tangible and centimeters also look familiar and comfortable.  I can even get used to grams and kilograms.  Grams are a bit too light to make complete sense, and the prefix kilo- makes it seem much heavier than it really is, but I can get used to that, too.  Liquid volumes have become more familiar, now that beverages often come in liter bottles.  I have had a harder time, though, with temperature.  So, I decided to make up a rhyme for myself to help me remember the approximate meanings of the different temperatures.  I wanted something relatively simple - possibly something I could use with kids.  Here is a poster with my first attempt.