zelda-skyward-sword
I'm inside the Great Tree. In front of me are two floating platforms, hanging from ropes. I can leap across to the first platform, but can't leap to the next, or to the ledge on the left. How in the world do I get to the second platform?
I've tried running back and forth to get the platform to swing. I've tried doing a spin move out of the water, but can't get high enough. The only result is more stillness.
You can pick up the Mushroom Spores using an Empty Bottle. Just walk up to the mushroom, hit it to knock the spores loose and scoop up the loose spores.
Those chests are scattered all over the world above the clouds, and can only be opened by activating the corresponding Goddess Cube in the the world below the clouds with your Skyward Strike. Once you do that the chest changes colour and can be opened. When a chest has been activated by a cube, it will show up on your map as a rectangular shape .
This is a Goddess Cube:
Here is a map containing the location of two activated chests (indicated by the rectangular blue symbol):
Here is a picture of an activated chest, which is now able to be opened:
(images taken from: http://www.ign.com/wikis/the-legend-of-zelda-skyward-sword/Goddess_Cubes)
Best Answer
Use the Gust Bellows to push the platforms apart. Then they will rock back to where you can jump on the next one and make it across.