Procedure:

1. build a platform no more than 8 blocks above a one block deep water source
2. Place a Skeleton on the platform.
3. Push the skeleton with your body such that it lands in the water.
4. Count how many attacks it takes to kill the skeleton .
5. Place a second skeleton on the same platform.
6. Hit the skeleton with a snowball such that it lands in water.
7. Repeat step 4.
8. Compare results of step 4, and 7.

Expected results: the first skeleton and the second skeleton should have the same amount of health

Observed results: !(Expected results)

This isn't all that serious it just means that you can't use projectiles for mob transportation in mob systems, if they fall 7 or so blocks into water after, which happens to be the exact height that mobs would fall after being knocked off a mob spawner into water in an optimized mob spawner farm