Decades-old physics 'sprinkler' mystery has finally been solved

A decades-old physics mystery involving a water sprinkler has finally been solved thanks to a new study.

New scientific information is continually challenging the way experts think about things, like when scientists witnessed a cracked piece of metal appear to “heal” itself.

Now, new information has come to light that seems to have put an end to a long-held debate over what would happen if a water sprinkler head was submerged and sucked in water, instead of spraying it out in spirals.

Hypotheses range from the sprinkler head continuing to spin like it does when it shoots water out, that it would spin the other way due to the opposite force, or that it might stand still.

The debate first came about when the question was posed by the mid-20th-century physicist Richard Feynman, and is now known as the Feynman’s sprinkler problem.

A group of mathematicians have taken a stab at settling the debate for good and have published a study with their results in Physical Review Letters.

The group from New York University built an ultra-low-friction rotary bearing, allowing their custom-made reverse sprinkler to spin freely to ensure nothing counteracted the natural forces and changed the results.

The sprinkler device possessed two curved arms made from tubes, as well as a siphon that would suck water in from the top when submerged in water.

Other instruments such as coloured dye and high-speed cameras were used to record and witness the water flow to infer their results.

A sprinkler in slow motionwww.youtube.com

Leif Ristroph, New York University mathematician and one of the authors of the study, explained: “We found that the reverse sprinkler spins in the 'reverse' or opposite direction when taking in water as it does when ejecting it, and the cause is subtle and surprising.”

They found that, although the sprinkler did go in the opposite direction, it was not a steady spin and was 50 times slower than a regular sprinkler that was not submerged in water.

Sign up for our free indy100 weekly newsletter

How to join the indy100's free WhatsApp channel

Have your say in our news democracy. Click the upvote icon at the top of the page to help raise this article through the indy100 rankings