I wanted to send along a list of the “big ideas” in measurement for primary grades. As you recall from our conversations, the primary curriculum has changed with respect to the measurement strand. The learning outcomes promote exploration and comparison in a developmental way through grade 3, when we introduce standard units of measure like cm and m.. In considering lessons for primary then, it’s a good idea to construct experiences around the big ideas, such as the following…
• When we measure, we compare.
• When we measure, it’s a good idea to line things up – to use a common baseline.
• When we measure it’s important to use the same units (all unifix or all straws for example and not a mixture of them)
• Mathematicians know that when we change the size of units we use, we get a different measurement for our object.
• There are many aspects we can measure. (height, mass, capacity)
• It’s a good idea to choose big units to measure big things and small units to measure little things.
• When we can’t bring 2 things together to compare them – like a door and a window – or when something is curved, we can use another object as a measurement tool (like a piece of string). Mathematicians call this indirect comparison.
• We can measure how many units it takes to cover an object – to see how much space it takes up.
• Mathematicians use personal referents when they think about standard measures – like the width of a finger (1 cm) or the length of a giant step (1 m).
I hope this list proves helpful.