Comment: Feedback Physics World  March 2018

Flipping physics

In response to a Quanta story “Water-flipping physics” (February 2018) about the viral Internet craze of flipping a bottle of water until it lands upright.


New balls please Tennis balls in bottles may be used in the classroom to demonstrate flipping physics (Shutterstock /Passakorn sakulphan)

Being the coach of a junior football club, I am only too aware of the water-bottle flipping phenomenon, which, at least in Derbyshire, shows no sign of abating. What intrigued me most from your article was the suggestion from Netherlands researchers that a classroom demonstration could be carried out using two tennis balls inside the bottle. How, pray, does one get two tennis balls inside a bottle? Quantum tunnelling?

Simon Edwards

Idom Merebrook, Derbyshire, UK

The editor responds:

A good question Simon! I looked up the paper (arXiv:1712.08271) and the researchers use what they call a “tennis bottle”, which is a cylindrical bottle without a neck.