Design Idea wk5: Mechanic driven
As James said it is okay to write design idea without following the design idea instruction given, so I have come up with a game that does not use fluid dynamics. Although it does not use fluid dynamics, it is still related to physics knowledge. It applies the lever idea as basis.
The aim of the game is simple, given the lever and the object, and the target, player has to hit the other side of the lever so that the stone/object can be transferred into the target basket, like this:

As players proceeds on to higher levels, the target basket will be smaller and smaller and eventually be just enough to let the stone in, so the challenge of the game actually increases over levels. Also, instead of using one sized lever, the lever length varies, so that the player does not get too used to the same length of lever. The longer the lever, the greater force player will need. The pivot point will change as well. The closer the ball is to the pivot, the greater force player needs. It is in expectation that players will need to try a few times and experience on the projection before they can get used to the lever as well as the pivot point. At later stages, we can even add in wind direction. Say if the ball goes against the wind, the player will need to hit harder to offset the wind. On the other hand, if the ball goes along the wind direction, then player cannot hit too hard, otherwise, it will be too far away from the target basket.