Why Dual Systems Of Measurement Are Important For Kids To Learn

Recently, I wrote about how measurement can be confusing for children and why that might be. I've been thinking about this a lot lately and I decided that I needed to explore this further and provide some ways to help it all make sense. I hope these tips help.

Sometimes I stop and think about how mixed-up measurement can feel, even for us as adults. We check the outdoor temperature in Celsius here in Canada, but in the United States, the temperature is usually shown in Fahrenheit.

In Canada, we buy gas in litres, but in the U.S., people buy it in gallons. We measure water in millilitres for a science experiment, and then we use cups when we bake. We talk about kilometres or miles when we drive, and we measure our height in feet and inches.

​Even as adults, it can be a lot to keep straight, and it’s no wonder our students sometimes tilt their heads and ask, “Why do we use both?”

That’s such a good question, and it’s one I’ve thought a lot about over the years.

Sometimes we tell children, “Science uses metric,” and that’s true in many cases. Most scientific experiments are done usining the metric system. Metric units are used because they are built on tens and can be used universally. This makes converting measurements simpler and easier to share around the world. But even that isn’t the whole story.

Some tools and situations still use the traditional units we’re used to. Cups, ounces, feet, inches, Fahrenheit, these all exist because people have used them for a long time, and the world didn’t start with only one system.

Children notice this, and their curiosity is the perfect starting point for learning.

One thing I always like to point out is that many tools actually show both types of units.

A ruler might have centimetres on one side and inches on the other. A measuring cup may show millilitres and cups. Some thermometers even display both Celsius and Fahrenheit.

​These tools make it easier for children to see the same measurement in two different systems. They can look side by side and compare numbers, which makes the idea of mixed measurements much more concrete and less confusing.

A simple way to explore this in the classroom is by letting children become “measurement detectives.” Give them common tools such as a thermometer, a ruler, a measuring cup, or a scale, and ask them to look closely at the units on each.

Together, notice patterns: some tools use metric, some use traditional units, and some might even be tools they’ve seen at home rather than at school. Children begin to see that the same concept,  length, volume, or temperature, can be measured in more than one way.

​Even young children can notice this difference, and just noticing is the first step toward understanding.

As children share their observations, ask gentle, concrete questions: “Which units do you see most often?” “Which tools are used at school, and which have you seen at home?” “Do the same measurements sometimes use different units?”

These questions help them make sense of the mixed measurement world we live in. They don’t need to decide which system is better; they just need to see that different tools and situations use different units, and that’s okay.

As I watch children explore the tools and units around them, I’m always reminded that noticing is the first step toward understanding.

​Simply giving them space to see how centimetres and inches, millilitres and cups, Celsius and Fahrenheit relate to each other can make a huge difference. 

The light bulb comes on as they start to see the connections, and they begin to develop the tools to handle the different real-life situations.

In my next post, I’ll share a few simple activities you can try with your students to help them connect these observations to real situations, so they begin to understand why different units exist and how they’re used in daily life. 

​Check out my recent blog post to get free resource using non-standard measuring units as a start to exploring the world of measurement.

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