A question for you – which of the five containers in the picture do you think holds the most water?
I instinctively guessed the big green shower gel, but the answer – you might be surprised to discover – is our trusty little orange tea pot!
Although very different shapes and sizes, the four bottles each hold 250ml whilst the teapot holds 270ml.
Bath time is a great opportunity for pre-schoolers to explore volume and capacity and make some surprising discoveries for themselves.
Tipping water between two containers that are different shapes but hold the same amount of water will allow them to discover that it’s not just how tall something is that matters, but also how thick and wide.
Intuitively, lots of us aren’t great at estimating how much different shaped objects hold and would usually guess that the tallest holds the most – something big brands exploit are very good at exploiting! This can make questions of volume and capacity tricky for us when we first encounter them formally at school.
But lots and lots of hands on experience and visual memories in the early years can really help.
A quick scavenge around the bathroom and kitchen cupboards should produce some great containers of different shapes with the same capacity that you can add to the bath toys – I’ve got my eye on a whole load that I’m just waiting for us to finish off! A small set of plastic funnels is also really handy for pouring between bottles.
Some other ideas that can help build up your child’s stock of visual memories of capacity are ..
- A tall thin beaker and a short fat cup that holds more
- Something square and something round of similar heights that hold the same e.g. box & saucepan
- Related items that hold part of something else e.g. 2 cups that each hold half as much as a plastic jug
- Small containers that can be used to fill a big container – e.g. yoghurt pots and a big bucket – so you can count how many of the small containers it takes to fill the big container
- A tall container with thick lining that holds less than a shorter container with thin lining which will help you explore the difference between the volume – the amount of space something takes up – and capacity – the amount of space available to be filled with something else
It’s also great to make all these different containers available at different times in sand so you can see that the same “rules” hold for sand as they do for water. And you can then move on to seeing what happens when you mix sand and water …. but that’s a whole different set of questions again … 🙂
For more maths ideas check out my maths pin board …
I would love to hear your ideas, do link them up below …
Number & Maths
Finally, I’d like to thank my mum for her help with this post – as with almost all my science and maths posts, it is based on ideas that she developed over many years in the Pre-School Playgroup Association.