Explore concepts such as density, buoyancy, air pressure, and Archimedes' principle with these cool Jellyfish Divers. Fill an old soft drink bottle with water, pop the Jellyfish Diver inside, screw on the lid and give the bottle a firm squeeze. Can you make the Jellyfish dive down to the bottom? Release the squeeze and it will return to the surface again! For an extra challenge, can you get the jellyfish to spin around in the bottle?