Heavier or Lighter?

Compare the weights of objects using a balance and then sort the objects into two groups
based on their weights.

Low teacher engagement


  • Balance
  • Collection of five different objects. Choose objects that are small enough to fit in the
    balance cups and have different weights. (TIP: To increase students’ engagement,
    use materials they are not used to seeing.)
  • One base/reference object that students will use to compare the weight of the other
    objects. It should be of medium weight, different from the five objects, and fit in the
    balance. If needed, put a sticker on the base object to identify it.
  • Two containers to sort objects into “heavier” and “lighter” piles or the provided recording page to record the weight of the objects.

Setup — Less than 5 minutes

  • Gather the materials.
  • Place the base object, collection of objects, balance, two containers, or the recording
    page in the center area.


1. Students compare each object from the collection to the base object one at a time by placing the object on one side of the balance and the base object on the other side.
2. If an object is heavier than the base object, students put it in the “heavier” pile. If an object is lighter than the base object, they put it in the “lighter” pile.
3. Optionally, have children record the category for each object on the recording page and then move it to the corresponding pile.

Checks for Understanding

To deepen children’s learning about early math concepts, talk and ask questions while doing this activity together. Here are some examples to get you started.

Measuring Weight

“Which object feels heavier?”

Use an object that is a very different weight than the base object: “What happens when you put this object on the other side of the balance?”

“When you look at the balance, how do you know which object is heavier?”

  • “You figured out that the banana is lighter than the toy tiger, so where does the banana go? What other things were lighter than the toy tiger?”
  • “What are some things that are the same about all the objects in this pile?”
  • “Is your object heavier or lighter than the base object?”
  • “I see that both the penny and the block are lighter than the toy elephant. Which one is the lightest? What does it mean if something is the lightest?”
  • “Which one do you think will be heavier? How did you know that?” After weighing the two objects: “Which one is heavier? Did you guess correctly?”

Activity Modifications

Once you have tried out the activity, here are some other things you can do. Try these modifications to keep the activity interesting and challenging for students all year.

Introduce a Variation
  • Increase engagement by having students collect their own objects to weigh.
  • If you don’t have a balance or you want to add a variation to the activity, have students compare weights of objects by hand. Make sure the objects have very different weights to make comparison easier.
  • Count how many objects are heavier and lighter than the base object. Keep an ongoing count or tally for different base objects.
  • After weighing all objects, have students order the objects from lightest to heaviest.
  • Introduce non-standard units by weighing a base object, then weighing a lighter object, then adding more units of the lighter object to see how many it takes to outweigh the base object.
    For example, weigh a dry erase marker on one side and then add Unifix cubes to the other side to determine how many Unifix cubes it would take to outweigh the dry erase marker.