Episode 5: Fun with Antibubbles

Astronaut and chemist Dr. Don Pettit does physics demos that are out of this world. Currently on board the International Space Station, Dr. Pettit presents fantastic physics that can only be demonstrated in micro-gravity.

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Challenge Question: When the water sphere rotates, why do the bubbles center themselves?

Challenge Answer: When gravity is taken out of the equation, I can only see another force that acts on the bubbles: the centrifugal force. Water is denser than air so it is pushed to the outside of the bubble as it feels a greater centrifugal force (but H20 also has strong intermolecular forces so it doesn`t scatter) and air is accumulated in the middle (as the other space is taken by the water).

Challenge Winner: Lidia Luque of Rubi, Spain