The Pool Deck Is a Maths Room
Four short lessons on the numbers every swim family already handles: a clock that counts to sixty, times kept to the hundredth, yards against metres, and a sport where the smaller number wins.
For grown-ups, from what SplitForge teaches children at Spark & Anvil.
- Lesson 1The clock counts to sixty
- Lesson 2Hundredths, and a borrow of sixty
- Lesson 3Yards and metres
- Lesson 4The smaller number wins
The kitchen pace clock
You'll need: The printed Deck Clock face (or any clock with a second hand), a pencil, paper.
- Print a clock face from the Deck Clock, one for each person.
- Before anyone draws, everyone writes a guess: what shape will a :40 send-off make? A :45? A 1:35?
- Draw each one by jumping the pencil round the dial by the send-off, joining the dots, until you land on the top again.
- Compare the shapes with the guesses, and say why the :45 and the 1:35 differ.
Open The kitchen pace clock: run it, or print the seat sheets →
A little history, and what nobody knows
The clock
Counting in sixties began with the Sumerians in the third millennium BC and passed to the Babylonians, which is why a minute still has sixty seconds. Sixty has twelve divisors, and those divisors are where a pace clock’s shapes come from.
Why they chose sixty is not settled: historians find its origins less simple than the usual stories tell.
Source: Sexagesimal (Wikipedia)
The hundredths
At the 1972 Olympics in Munich, Gunnar Larsson and Tim McKee both swam the 400 m individual medley in 4:31.98. Larsson won by two thousandths of a second, and after that no swimming race was to be decided by less than a hundredth.
Which of the two was really faster cannot be known from a gap that small; the source does not say why the line was drawn at a hundredth.
Source: Swimming at the 1972 Summer Olympics, men’s 400 m individual medley (Wikipedia)
The same idea, with the world taken away
A clock counts to twelve. If you jump by five each time, how many places do you visit before you are back where you started?
Ask it, then let everyone say the answer in their own words. A child's rung on Spark & Anvil ends the same way, with the world gone and the numbers left.
The same idea at every age
- Ages 3–5Bead a Length and 3 more
- Ages 6–8Fives Round the Clock and 3 more
- Ages 9–14The Star and 9 more
- Ages 15–18The Points Curve and 3 more
Your child will meet this idea again at every age. The tools and courses here are the part for you.