Pan Balance -- Shapes

  • Pan Balance – Shapes


    Build up to algebraic thinking by exploring this balance tool using shapes of unknown weight. Challenge yourself to find the weight of each shape in one of six built-in sets or a random set.

    Two other tools, Pan Balance - Numbers and Pan Balance - Expressions, are natural extensions.

    This interactive is optimized for your desktop and tablet.



    • Begin by choosing a set from the top menu. Random creates a new set every time you choose it.
    • Each shape is assigned a certain weight.
      • Try to find equivalent sets of shapes by places shapes on each side of the balance.
      • To grab a shape, mouse over the shape you want, move your cursor to the desired pan, and click to drop it.
      • To remove a shape, click it.
      • The pans move according to which side is heavier and which is lighter.
      • When both sides of the pan balance, the equivalent relationship is added to the right-hand table.
    • When you think you know any of the weights, you can check your guess.
      • Click Guess Weights at the bottom when the pans are balanced. This brings up the Guess Weights screen.
      • Enter your guess beside your desired shape, and then click Check. Correct values get a green check. Incorrect values get a red X.
      • Click Close to return to the balance screen. Note: All shapes always have positive whole number weights.
    • There are four additional buttons at the bottom to manipulate the tool:
      • Reset Table: Removes all entries from the table.
      • Count Items/Show Array: Toggles between what is shown on the pans, either counts of how many there are of a shape or each shape separately.
      • Reset Balance: Removes all shapes from the pans.
      • New Weights: Changes the weights of the shapes when you are in Random mode only.
      • When you are finished with a set, select another one from the top menu to changes the weights of the shapes.