Answer:
Issuen Shingeki... Messatsu!
Step-by-step explanation:
What you've just witnessed is something called "Buoyant force".
Buoyancy is the upthrust in the particles between the Atoms of the leaf and the water. They have the opposite charge, allowing them to repel each other- Ultimately allowing the leaf to float.
Or simply, the leaf is lighter and is less dense.