School In The Bath Tub

He practically schooled himself on the topic of volume while he bathed.

I wrote about this in Fun-filled Math Conversations With Your Child .  Notice the purple 330ml Ribena carton floating in the bathtub and the white basket filled with his bath toys!

I’ve reproduced Chapter 11 Volume below for your reading pleasure.


My little son loved to play in the bathtub.  Often, he would run dripping wet into the kitchen asking for containers to play with. Eventually his bath toys included straws, syringes, plastic pumps, water bottles, milk cartons, spoons, measuring cups and more. Needless to say, he schooled himself on this topic of volume while he bathed.  

We had a name for each toy so that we knew exactly what each other was referring to when we conversed outside of bath times.

Transparent plastic measuring cups and water bottles with measurement marks made great learning tools for us.

“This is a 500m water bottle.  See this 500m marking?  If you fill this bottle beyond this mark, there would be more than 500m.

“Do you see these
markings on the side of the bottle?  If you fill the bottle to this mark, you will have 100m of water,… and 200m here,… and 300m here…and 400m here, and of course 500m here.  This space in between 2 markings is called an interval.  Get it?”  I point to the markings as I spoke.

“So, if the bottle was filled halfway, and the water level was between the 200m marking and the 300m marking, how much water would there be?” (250mℓ)

“Shall we fill this milk carton to the brim?…What happens when I squeeze the carton? …Yes, the water will overflow,… that is because the volume of the container is reduced,… but has the carton become smaller?”

Composing spontaneous questions incorporating math (and science) language is an art that required background work on my part, to familiarise myself with the subjects.

“Let’s fill the water bottle to 300m… and  let’s drop 10 marbles (or stones or toys) into the bottle.  What is the new water level? (about 350m)

The marbles displaced the water by 50m.

What do you reckon is the volume of the 10 marbles?”

As always, I doodled tables in my son’s jotter book for him to record the measurements of his bath toys.

Toys Volume
Water Bottle 500 mℓ              0 . 5 ℓ
Milk Carton 1000 mℓ              1 . 0 ℓ
10 marbles 50 mℓ              0 . 05 ℓ
Tablespoon 5 mℓ                0 . 005ℓ

When it was time to formalise his understanding at a sit-down lesson (many months later), I drew this in his jotter book : 

“Let’s recall.  These are called markings and the space in between them is called …interval.”  I gave him time to recall while I wrote it down to prompt him.

You know that 500m plus 500m equals 1000m, right?  And you know that 1000m equals 1, don’t you?”  I write in large fonts as I spoke:

I guided him through the conversion of litres to millilitres and vice versa, limiting my questions to only mulitiples of 100mℓ for the start. When I was confident that he would be able to tackle practices on his own, I gave him some.

The conversion of the more complicated volumes below 100ml (eg 25ml, 5ml) were reserved for later day.


By the way,  I read somewhere that we all experience creativity when we shower or take a bath because of the rush of alpha waves in our brains when we are in water!  Isn’t that perfect?

Try it! 💐

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