Investigating Capacity

I bought a set of plastic measuring beakers (from Amazon) so the girls could get a feel for equivalent volumes in different sized containers. We just used water as the liquid, but I dyed it with some food colouring to make it easier to read the scales on the beakers.

First, I poured 50ml into the smallest (50ml) beaker and asked the girls to tell me how much liquid was inside, i.e. what was the capacity? Then I asked them to find the next largest beaker (100ml) and to tell me what they thought would happen if I poured all the liquid from the current beaker into that one? This seems like a pointless question, but it's easy to forget just how innocent children are when they have no prior experience of something! One of them said nothing would happen, just that it would all fit inside... Which it did! And so I asked them to tell me how many ml of water were inside this beaker. Note that to them it only looked half full as opposed to a full beaker before, so they were surprised to read the scale and see it was 50ml. To be honest, I was surprised they were surprised. 😂

We continued: I asked them to find the next largest beaker in size (250ml) and, again, what they thought would happen if I poured all the liquid in the current beaker into that one. This time, one said that they would end up with less water like last time because it wouldn't be as full... So we poured the water in and read the scale - still 50ml - and I asked if there was less water in the beaker or the same amount? She said less because it was less full, but her sister said no, there was still 50ml so it was the same amount - though she said it in a questioning tone herself. 😂

Again, they found the next beaker (500ml) and again, I asked them what they thought would happen... This time, they recognised that it would still read 50ml but they said it would look like even less because the beaker was bigger! And finally, we repeated the question again for the 1000ml beaker. When we poured the water in they all (including the 2 year old lol) found it hilarious how it was just "a little line at the bottom". 😂

To complete their understanding, I picked up the 50ml beaker again and asked them what they thought would happen when we poured the liquid from our current beaker back into this one... Would it fit? How full would it look? They both said yes, it would fit because that's where all the water started from! One asked if it would look almost empty like the 1000ml did, to which I asked her if that's what she thought would happen and to which she just laughed. Lol. So we poured it back into the 50ml beaker and they all squealed with delight to see it full to the brim. 😂😂

So if you're looking for a quick and easy "magic trick" to amaze your young kids, you know what to do! 😆

Next, I put a few different sized drinking vessels on the table for them to practise etimating with: one of their plastic cups, Papa's mug for tea and Mama's glass for water!

We poured water from the jug into them in turn, estimated what the capacity of each one was and then decided which beaker was the most suitable for measuring the actual capacity: i.e. would it be sensible to use the 50ml beaker? No! Why? Because the water would't fit and just spill over the edge. What about the 1000ml beaker? No, because the water would fit but it wouldn't fill the beaker properly and it's harder to see what the capacity is - brief introduction to accuracy but not the focus for this time so didn't go into it too much! Just that look, the 1000ml beaker doesn't have 50ml on it so we had to guess it was about 50ml in there but the smaller beakers did have 50ml on them so we could just read it easily.

Finally, I let them have some (supervised!) play with the water and beakers, so they could observe what happened to the perceived volume of water when it was poured between the different sized beakers and compare it to the actual reading on the scales!

When we finished and it was time to tidy away, the two-year-old wanted to help by stacking all the beakers up. MashaAllah she independently sorted them into size order first, then put them inside each other starting from the largest. 💕