Scales are found in pairs or, in one case, 2 pairs, only in Pikmin 2 and only above ground. They are found one low enough to walk onto, the other higher but still low enough that Pikmin can be thrown onto them, and their purpose is to provide access to higher ground. To manipulate them, throw Pikmin onto the higher of the two. On whichever block the weight of Pikmin (displayed above the block) is greater, that falls to become the lower block. [edit]Use
To use the blocks, stand on the lower one and throw one more than half of all your Pikmin onto the higher scale, at which point the Captain and Pikmin left with him will raise up, allowing them to walk onto the ledge above. The Pikmin Captains apparently weigh nothing, or at least have negligible weight. Unfortunately, this means some Pikmin must be left behind, leaving you with fewer up the top and the chance of forgetting where the others are. Fortunately, there are a number of ways to get around this. With two Captains, have one remain at the bottom and take the other to the top by outweighing him with one Pikmin. Next, throw all the Pikmin from the lower Captain to the higher one. The drawback is that this allows only one Captain to get to the top. Alternatively, you can throw all Pikmin up onto the target ledge except one, then use that one to outweigh both Captains (on the lower block) and raise them to the higher position where the other Pikmin are. This, however, leaves one Pikmin down below.
2 pairs in Awakening Wood. 3 pairs in Perplexing Pool.