The year's last measurement is the sneakiest: not length, not time, but rotation. The descriptor asks children to identify, describe and demonstrate quarter, half, three-quarter and full turns in everyday situations — and every one of those words is a fraction of a circle, the very circle the fractions unit shaded and the clock unit swept. A turn is an amount, it has a size, and the size has a name: that is the whole idea, and the body is the best instrument for measuring it.
The turn dial
One arrow, one circle. Every press sweeps exactly one quarter of the way round.
Facing the start — no turn yet.
Four landmarks on one circle
The dial gives the four turns their places: a quarter sweeps one corner of the circle, a half faces you exactly backwards, three quarters leaves just one corner to go, and a full turn brings the arrow home with the whole circle shaded behind it. Children should stand up and be the arrow — the descriptor's demonstrate is meant literally — because the feeling of facing backwards after a half turn anchors the word better than any diagram can.
Two ways to turn
The same quarter turn can go two ways, and the ways have names borrowed from the clock.
Two ways to turn: the way clock hands travel, and the other way.
Named after the clock
A turn has a size and also a direction, and the directions borrow their names from the previous unit: clockwise is the way every clock's hands travel, anticlockwise is the rebel direction against them. In Australia we say anticlockwise where some countries say counterclockwise — same idea, same clock. The deep fact hiding in the toggle is undoing: a quarter turn one way is cancelled by a quarter turn the other, which is a child's first taste of an inverse operation, wearing a costume.
The spinning kid
Stand in the middle of a room and turn. The descriptor says demonstrate, so demonstrate.
You face the whiteboard. Make a half turn. Where do you face now?
The room is the protractor
Inside a room, turns become visible without any numbers: face the whiteboard, make a half turn, and the bins are suddenly in front of you. This is the pathways unit returning — turn right there was always a quarter turn clockwise here — and it is the cheapest classroom equipment in mathematics: a child, a room, and four things to face. Families can play it at home with the fridge, the window, the couch and the door, one spinner and one caller at a time.
Turns in the wild
Taps, lids, handles and clock hands all turn. Name the turn each one makes.
The minute hand has gone from the 12 round to the 6. How much of a turn is that?
Reading turns off the world
Once the names exist, turns appear everywhere: a tap opens with about a half turn, a door handle drops through a quarter, a jar lid spins through several fulls, and the minute hand performs a perfect full turn every hour. Naming the turn an object makes is the descriptor's identify and describe in the wild, and the pale-to-dark arrows in the game train exactly that eye: where did it start, where did it stop, and how much circle lies between.
Turn the key
A wind-up robot only turns clockwise. Compose quarters and halves until it faces its exit.
The exit is on your left. Turn the wind-up robot until it faces the green mark.
Turns that add up
The wind-up robot only turns one way, so reaching an exit on the left takes either one three-quarter turn or a quarter pressed three times — and discovering that those are the same thing is discovering that turns compose: quarters add to halves, halves to fulls, exactly as fractions do. With that, the measurement strand closes and so does Year 2 itself. After a year of tens and arrays, clocks and calendars, maps and graphs, the year ends facing the way it began — a full circle.
Quick self-check
1. A half turn leaves you facing...
2. Two quarter turns the same way make...
3. A full turn leaves you facing...
4. The minute hand going from the 12 to the 3 makes...