Bowl Riddle Solution (Plus 2 BONUS riddles) ft. Kurt Hugo Schneider part 2/3

For the bowl riddle, if you found something to cover the water with, and then inverted the whole lot, bouyancy would push the ball to the top of the bowl. Of course, you would struggle not to touch the ball with the cover, so that kind of violates the last rule. If you had a really good pair of lungs and a long straw, you could blow lots of bubbles in the water below the ball, which might lower the bouyancy sufficiently to allow the ball to touch the bottom. Finally, though not going to work in the exact bowl setup you have there, you could spin the bowl sufficiently to throw all the water to the sides, allowing the ball to fall down the middle.