What is it?[edit | edit source]
The Romaurie Effect (Romaurie-Effect) is a particular design of aquarium tank in which the use of gravity and a vacuum are used to good effect to create a tower of water.
Imagine a tall column type aquarium tank standing open side down inside another very shallow aquarium.
You then raise the tall tank a few inches off the floor of the shallow tank and fill the shallow tank with water. As the water level rises you place a hose into the air filled tall tank and remove the air. As you do this the water level within the tall tank rises so you add more water. You continue to do this until the tall tank is filled with water.
The weight of the water in the tall tank is held back by outside air pressure and water cohesion.