7 year old and his science question

My son was in the bath tonight and he discovered something I could not explain. He had a bowl and he "stuck" it to the side of the tub. Somehow the force of the water below it helped it adhere to the side of the tub almost like suction. The bowl sort of floated on top of the water but remained stuck to the side of the tub. Can anyone understand and explain the science behind it so I can get explain to him?

Just seeing this. It probably formed enough of a seal and had a pressure differential between the inside if the bowl and the water outside it. I'm assuming the opening of the bowl is to the side of the tub. Its how a suction cup works. You squeeze out the air underneath the suction cup, causing a lower pressure under the cup than the air around it.