Place one red square on the left pan and one blue circle on the right pan. Are they equal in weight? If not, which weighs more? Try to make the pans balance by adding another shape to one pan. Which pan should get another weight? Why?
Continue adding either red squares or blue circles to the pans. When the balance, an entry will be added to the table. Do you think you know the weight of the blue circle? Check by clicking the Guess Weights button and entering your guess.
Is there another combination of red squares and blue circles that will make the pans balance? Try to find at least one more.
Conduct similar investigations to find out how red squares and blue circles are related to pink triangles and yellow diamonds.