dipper

The first 3D shape shows a cross section of a dipper that uses air pressure to hold water. Holding the knob on top between your index and middle finger, submerse the container in water. Then plug the hole in the knob with your thumb and lift the dipper out of the water. Water will stay in the container until you remove your thumb.

The project is to explain the physics involved and make a design based on them to demonstrate how they work.