Jump in the bath or get the water table out for this one.
You'll need containers of various heights and widths. Beakers, yoghurt pots or empty shampoo bottles will all do.
Take two identical bottles. Fill them to the same height. Do they contain the same amount of water? Your preschooler should say yes. Now pour the contents of one of those bottles into a third, wider container. The water level will be lower in this one, of course. Do they still contain the same amount of water? Of course they do, but your preschooler will say no. They do not yet understand conservation.
To a preschooler, the tall, thin bottle looks like it contains more water than the short, fat one. They think that some of the water disappears on its way to the wider vessel. The water is not conserved.
Other fun ways to test for conservation:
- Take two balls of play dough. Stretch one. Do they both still contain the same amount of dough?
- Arrange two identical lines of coins in parallel. Now stretch out one line so that it's longer than the other. A preschooler believes that there are now more coins in the first line.
So what's the answer? How do children eventually understand conservation?
Lots of it. Lots of free experimentation with sand and water, play-dough and loose parts.
Why do we insist on teaching our children maths and science before they have had the chance to get a sense of what these concepts really mean? Once you have a feel for number, learning arithmetic at school is easy.
Here's the rest of the series:
Encourage open-ended play for creativity and focus
Understanding schema play in toddlers
Independent play and why it matters
Insider Guide: Small World Play and Language
Tell Almost Any Story with Just a Handful of Figures
A simple guide to choosing the right toy