Chapter 16 - Consistency in Units

Measuring units – it seems so straightforward and simple, doesn’t it?  I mean… where could anyone possibly go wrong? You take a measurement tool and you measure an object.  Simple! No... apparently not.  The text brings up a great concern.  After students develop a concept of an attribute through comparison activities, they can move onto the measurement process.  Common questions can be something like “How long is the pencil?”.  The interesting scenario that the text brings up is that young children oftentimes don’t understand that units have to be equal size.  For example, they might measure something with pencils of different sizes and report that the object was three pencils long.  The problem would be the inconsistencies in the different sizes of pencils used to measure.  They are correct – the object is three pencils long… but three different sized pencils long.  I would imagine explaining that they have to use a constant unit for measurement would be difficult.  Besides telling them they have to use one unit, I wouldn’t really know how to explain further.