I’ve been using this algebra balance in my Algebra 1 classes to illustrate concepts having to do with equations. This balance is unique in that it has two pans on each side. The yellow pans represent positive quantities and the red pans represent negative quantities. The white chips and the green containers (representing the “x”) have the same weight so you can easily set up simple equations using the pan.
It’s been a minor hit so far. Students seem to understand that you can maintain the balance by adding or taking something away from each side of the balance. This and next week we’re working on making the appropriate moves on the balance and solving equations without the aid of the balance. I’ve gotten students used to solving equations like “2x-1=9” by inspection; the unintended consequence of this is that students are a bit puzzled why I’m going through so much effort how to add 1 to both sides, etc.