Using balance scales to explore mathematics

Today we dragged out our old balance scales to explore. They needed a little bit of attention, so we added two baskets (one to each end) and attached them with some wire. At this point both baskets were empty and of course level with each other on the scales – they were balanced.

We initially began to discuss the concept of ‘why does the basket go down’ when just one glass bead is placed in it. This led to some really good thinking, some great dialogue and it was clear to see the children developing their understanding about how these scales worked.

Makenzie “If you put more in here it won’t be the same level, cause ones down and ones up, cause there’s too much in here”

Pesiki “When you add the bead the basket, it’s going down. There’s nothing in the basket then it will get heavy (when the bead is added)”

Katie “This one goes down more as it’s the heaviest”

Ryan L “When nothing's in them, it’s going to be the same height”

Sharing and discussing ideas and listening to new perspectives

We familiarised ourselves with the scales, using different objects, the same objects, large and small objects in the baskets, all the while trying to predict what would happen.  A real surprise occurred when someone put one of our heavy but relatively small butterfly beads in one basket and a large pine cone in the other basket. All the children predicted the pine cone’s basket would go down, meaning it was heavier. But no, it was the glass bead that was heavier than the pine cone. This lead to some lengthy discussion about the size, weight and density of objects.  

After some more experimenting the children discovered that sometimes even though an object is large, it can still be light.

Constructing knowledge

As the morning went on and we had explored heavy and light we tried to work on finding different objects that would weigh the same. What a tricky task this was. In one basket went Tyler's globe, and we all estimated how many glass butterflies we would need to add to the other basket to make them balance. Our observations were then recorded through a simple chart.

Trial and error 

Predicting

Estimating

Observing

Working collaboratively with others

Here Ollie holds the scales still while the baskets get filled up with objects. After everyone has checked the contents and after some careful thought decided which basket they think is the heaviest, Ollie lets go. Hmm...who will be right?

Counting and sorting

Mathematical learning involves ‘exploring objects, materials, and events by acting upon them and noticing what happens’ and ‘engaging in simple investigations in which children make predictions, gather and interpret data, recognise patterns and draw conclusions’ (Ann Epstein, 2007)

Christine