All Exhibits
Giant Bubble
Step onto the mat and pull the ring and surround yourself in a giant bubble!
The bubble is trapped between two rings. What shape do you think it will make? Was your prediction correct?
If no one was inside the bubble, how big could the bubble be?
A bubble will always try to make itself as small as possible. The smallest shape is usually a sphere, unless the bubble is trapped between some other objects. In this activity, the giant bubble is trapped between two rings. When you pull the rings apart you make a tunnel-shaped bubble, with a ring at the top and a ring at the bottom. You might think the bubble will make a cylinder, but a cylinder is not the smallest possible shape for this bubble. Instead, the bubble curves inwards at the middle. This shape has a smaller surface area than a cylinder and is called a catenoid.
The curve of a catenoid is called a catenary, and is the shape made by a freely hanging rope or chain.
