Naledi and Hiroki are standing at the bottom of a swimming pool that is being filled with water. Naledi is wearing a balloon hat which lightly rests on her head, while Hiroki is holding an identical balloon at arm's length underwater. What will happen to the balloons as the water level in the pool rises?

Respond very briefly.
As the water level in the pool rises, both balloons will rise with the water. This is because the balloons are filled with air, which is less dense than water, causing them to be buoyant and float. Naledi's balloon hat will maintain its position on her head, staying above water as long as she stands. Hiroki's balloon, held at arm's length underwater, will exert an upward force against his hand due to buoyancy. If he maintains his grip on the balloon, it will remain submerged, but if he lets go, it will float up to the surface.