You can add a little Data Science into any lesson, but Measurement in Primary School is just crying out for a little added Data Science. And when I say Added Data Science, I really mean added critical thinking and scepticism. Here is a Grade 6 lesson that I just trialled at Gillen Primary School in Alice Springs, where we took a basic measurement lesson on height and injected some cool data concepts. This lesson might be worth splitting over two lesson times, depending on how the discussion goes.

The goal here is to be asking questions and evaluating what you’re doing at every step.

- Pick two students that are very different heights, and have them stand at opposite corners of the room. Have the kids guess who is taller.
- Now pick two students that are very close in height, and do the same thing. Have the two students stand back to back and work out who is actually taller. Now ask the kids: which was easier to guess? Why?
- Class discussion: what does it mean to “estimate” a value? What’s the difference between an estimate and a guess? If an estimate is an educated guess, what factors did you use to “educate” your estimate of who was taller? (One student today said that the taller person came further up the board than the shorter person, which was a great way of using comparisons to inform your estimate!)
- Have your students make a list of the people in their class who are here today and rank them by height, without talking to each other or comparing answers.
- Class discussion: Did you all rank every person the same? Which positions were easiest to rank? Often the tallest and shortest students are really easy to rank, but sometimes there are a few students very close in height that make it difficult. The middle positions tend to be the hardest, and you can have some discussion about why this is.
- Ask the class who is the tallest student. Take one answer and then ask if there are any different answers, until you have the set. Then do the same for shortest. You can do some back-to-back measuring at this point to settle these questions.
- Ask the class why their answers might be different, and discuss how estimates are not exact.
- Now get the class to stand up and sort themselves into height order. You might want to get the tallest and shortest up first, and then gradually fill in the middle one or two students at a time, to avoid chaos.
- Class Discussion: How much easier was it to do in person than try to compare them in your head? What made it easier?
- Now for the measurement! Put the class into groups of 3-5. Each group picks one person to measure, and every other person in the group should measure that person and write down their height, without telling the other members of their group what height they got.
- Groups compare their results and see how similar they were. Each group should record the size of the range of their measurements. So a group that recorded measurements of 143, 145, and 146 would record 3 as their largest, because the lowest value was 143 and the highest was 146.
- Come back together as a class. Class Discussion: How accurate do you think your measurements were?
- Class Discussion: Did every student use the same measuring technique? What were some different ones people used?
- Class Discussion: How big was the biggest difference between measurements? What factors made the measurements hard? We heard things like:
- The person we were measuring was taller than us.
- The person was taller than the tape measure (at this point you can explore strategies for solving this problem! Eg measuring against the wall, marking where the tape measure stops, and putting the tape measure above that mark to measure the remaining length, or measuring them lying down on the floor).
- It was hard to hold the tape measure straight.
- It was hard to hold the tape measure still.
- It was hard to read off the exact value because of the distance between the tape measure and the actual top of the person’s head.
- The actual measuring part of the tape measure starts a few centimetres in from the start of the tape, getting it exactly in the right spot on the floor is hard!

- As a class, brainstorm techniques for making the measurements more accurate.
- To wrap up the class, ask them again how accurate they thought their measurements were, and then ask them if they think they were accurate enough? Think of several scenarios where you might need to measure height, and ask how accurate each needs to be. The goal here is to consider that data is rarely completely accurate, but it can still be accurate enough. Eg.
- Measuring the length of bed someone needs. Because beds come in fixed sizes you only need to know which range the person fits into.
- Measuring whether someone will fit through the doorway. As you are very unlikely to have primary school kids who won’t fit through your doorway, it’s reasonable to think they don’t need to be very accurate! “Are you less than <however tall your doorway is>?” can usually be estimated rather than measured! Consider whether they might know someone for whom this would not be sufficient – eg a professional basketballer.
- Measuring whether a cape would fit
- Pilots in some aircraft have to be under a certain height to fit in a cockpit
- Sailors in a submarine (because the ceilings are low)
- What others can you think of?

There are many more questions you can explore using this lesson, and many more types of inaccuracies you could consider. As always, these steps are a starting point, and some points to ponder. You can use a subset of the steps, or expand on them.

If you modify the lesson it would be wonderful if you could share it back by emailing it to contact@adsei.org so that other teachers can learn from your approach.