Tips, Tools and Technology for Educators

Looking for a fun way to introduce students to the concept of equivalence? Try our free pan balance applet that we developed in conjunction with the National Council of Teachers of Mathematics (NCTM). It is freely available on their Illuminations website. The pan balance applet can be used with students in PreK (with some guidance of course!) all the way up through 8th grade to investigate relationships among the weights of various objects and explore the concept of equivalence.

How to use the pan balance:
Just roll your mouse to ‘pick up’ a shape and click to ‘drop’ it on to a pan. To remove a shape, just click on it to make it disappear. Watch the balance tip as students add shapes to either side. When the amounts on the left and right sides are equal, the results appear in the table on the right.

When students are ready to guess the relationships between shapes, they can click on the Guess the Weights button to enter the weights and then click on the Check button.

You can use the Reset Balance button to remove the shapes and the Clear Table button to remove the data from the table.

Each set has specific weights assigned to each shape. For an additional challenge, ask your students to click on the Random Set button!

Ideas for Exploration

1. Ask students to place one red square on the left pan and one pink diamond on the right pan. Are they equal in weight? Try to add more red squares or pink diamonds to see if they can balance the shapes. Which shape weighs more?
2. Once the students think they know the relationship between the shapes, ask them to add one shape on the right and then try to use logic to figure out how many of another kind of shape are needed to balance the pans.

Do you have other ideas on how to use this pan balance applet in your classroom? Let us know and we’ll feature them on our blog while giving you and your school credit!