As you explore with your child what you have noticed they are learning about measurement and number and the different ways we compare size. Size can be compared using volume, capacity, mass, time and temperature.
By estimating how much a container can hold your child is exploring the different language and tools we use to compare and measure. If an object is solid or big, you could use number and counting to talk about how many there are, compared to how you talk about lots of small objects.
When you talk about small objects you don’t use number or counting. Instead you can talk about weight or the number of packets.