Create a Balance Scale: Defining quantity and weight

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Using a balance scale can be a great way to help your toddler understand some math concepts!

A homemade balance scale helps a preschooler to visualize concepts like comparing heavier and lighter items, and can even be a tool to talk about quantities by demonstrating greater, equal to, and less than.

It’s a quick and easy project that packs a punch of knowledge!

How to make the Balance Scale math experiment

Supplies you will need

For the Balance Scale experiment, you’ll need:

  • A hanger with notches
  • String or yarn
  • Two plastic cups
  • Scissors
  • Small objects to place on balance scale
Supplies for homemade balance scale experiment

Before you start

You will need to use sharp scissors to cut holes in the plastic cups, so be sure to watch your little one while you are cutting the holes. Once the holes are cut, they have sharp corners. Watch your child’s fingers while placing the yarn or string through the holes.


Here is how to do the Balance Scale experiment with your toddler:

Step 1: Cut holes in both plastic cups

Step 1: Cut holes in both plastic cups

The holes should be across one another on each cup.

When I cut the holes in our cups, I ended up pulling the yarn up to the rim of the cup, allowing the yarn to drag the hole up. This ensured that the yarn was holding each cup in the same spot.

It’s easiest to use a hole punch when you’re cutting the holes, but since we did not have that available, I simply used a pair of scissors.

Step 2: Cut two equal pieces of yarn or string

Step 2: Cut two equal pieces of yarn or string

I pulled out between 2 and 3 feet of yarn and cut it. Then, I folded that long piece of yarn in half and cut the midway point so that I had two equal pieces of yarn.

Step 3: Feed the yarn or string pieces through each cup and create a knot

Step 3: Feed yarn or string through each cup and tie a knot

Try to keep the knots as close in size as possible to start the experiment with balanced cups.

Once I tied each knot, I pulled the yarn knots toward the top of each cup until the knots reached the rim of the cup. That way, there’s no sliding during the experiment and it keeps your cups in balance.

Step 4: Hook the yarn or string onto the notches in the hanger

Step 4: Hook the yarn or string onto the hanger notches

Simply hang your yarn from the hanger using the notches in the hanger. This is why it’s important to have a hanger with notches: you don’t want your yarn or string to slide off!

Get your preschooler involved: Have your toddler hook the yarn on the hanger so they can create the balance scale.

The science behind the Balance Scale experiment

This homemade balance scale teaches:

  • Comparing objects – finding differences between two objects you’re weighing
  • “Heavy” and “light” – how you know it’s heavier
  • Quantity – greater than, equal to, and less than

How it works

A balance scale is a great way to visualize a few concepts, like what it means to be heavier versus lighter, comparing objects, and talking about quantity with your preschooler.

Our balance scale starts by being completely balanced because we used the same materials for each side of the scale. We know it is balanced when the hanger is level with the floor and not tilted to one side.

When we add objects to each side of the scale is when we see the action begin.

If one side of the scale is holding objects that are heavier than the other side, the balance scale will tip down to the heavier side.

If the objects being compared are of equal weight, we will see that the hanger stays level with the floor (i.e. not tipping to one side).

This is a great experiment to allow your toddler to take over. Have them gather small toys, kitchen gear (like forks, spoons, or fridge magnets), or other small objects from around the house to compare.

Comparing objects

When you are comparing objects on the balance scale, it gives your toddler the opportunity to see how different objects add up to one another. Ask questions like:

  • “These two objects are different sizes but are balanced. Why do you think that is?”
  • “What do you think will happen if we only put an object on one side of the scale?”


This is a great opportunity to talk about “heavy” and “light”. Ask questions like:

  • “Before we add these two objects to the scale, can you tell me which you think is heavier?”
  • “The balance scale is tilted down to the side with this object. What do you think that means?”


By only using one type of object that you have many of (like pom-poms, for example), you can talk about greater than, equal to, and less than concepts. Ask questions like:

  • “Let’s count out how many we are going to place in each basket. Which number is greater?”
  • “Once we placed our items in, it looks like the balance scale is staying level. Why do you think that is?”

Even if your child cannot directly answer the questions, they are good to get the conversation started. Then, if your toddler is struggling, you can help guide them and practice with more examples on the balance scale.

More math experiments to try out with your child

FAQ about the Balance Scale experiment

What is the purpose of a balance scale?

Creating a balance scale is a way to visualize greater than, equal to, and less than concepts in math. It’s also a great way to explain what heavier and lighter means to a young child! While you can explain these concepts in words, it’s best described using something like a balance scale to incorporate play into the explanation. Plus, it gives a great visual when one side of the balance scale tips to the heavier side.

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