Jellyfish Diver

Sale price$6.00


The Jellyfish Diver is a science classic. The jellyfish floats in a bottle filled with water, then when the bottle is squeezed the jellyfish mysteriously takes a plunge to the bottom. Release the squeeze and up the jellyfish ascends to the top again. This kit also includes a fun activity where the aim is to hook a sunken weight and bring it to the surface.

Age: 7 +

What you get

Jellyfish Diver includes one coloured plastic jellyfish. You need to supply a 2 liter plastic bottle as the diving tank.

How does it work?

Buoyancy is the tendency of an object to float in a fluid. An object floats if it's lighter (or less dense) than the fluid, and will sink if it is more dense. The density of the Jellyfish Diver is made up of the plastic pipette bulb, nut, air pocket and water inside the bulb. When the bottle is squeezed, compressing the air inside the dropper and allowing more water to enter the bottle causing it to sink. When the bottle is released, the pressure drops again. The air in the dropper expands, pushing water out. This makes the jellyfish diver lighter, so it floats to the surface.


  • Floating, sinking and buoyancy
  • Relationship between air pressure and density
  • Difference in the properties of air and water


WARNING: CHOKING HAZARD Small Parts. Not for children under 3 years.

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