A balance is used for measuring mass of an object.
Beam balances, like a seesaw, measure an unknown mass by comparison to known masses.
Something like a seesaw is used for measuring mass of an object.
An object that can be used for measuring mass of an object is similar to what playground item?

* forces
* Slide
* barrel
* Seesaw
* Merry-go-round
* rockets
* Monkey bars
* matter