Physicists Reveal Time to Get Last Drops From Bottles

Brown University researchers use fluid dynamics to determine optimal draining times for common kitchen liquids.

Published on Mar. 5, 2026

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Physicists at Brown University have used the Navier-Stokes equations and experiments to determine how long it takes to drain the last drops from containers of liquids with varying viscosities. Their findings show that low-viscosity liquids like milk can be drained to 90% in about 30 seconds, while more viscous fluids like olive oil can take over 9 minutes. The research also helped one of the physicists determine the optimal time to wait before draining residual water from a washed cast iron wok.

Why it matters

This research provides practical insights into the fluid dynamics of everyday kitchen tasks, from getting the last drops out of bottles to properly caring for cookware. Understanding the physics behind these common occurrences can help people be more efficient and avoid wasting food or damaging equipment.

The details

The physicists, Ph.D. candidate Thomas Dutta and professor Jay Tang, used the Navier-Stokes equations to model the behavior of thin liquid films and combined this with experiments to measure the time it takes to drain 90% of various liquids from a tilted surface. They found that low-viscosity liquids like milk drain much faster than high-viscosity ones like olive oil. Dutta also applied similar calculations to help Tang determine the optimal time to wait before draining residual water from a washed cast iron wok, which turned out to be around 15 minutes.

  • The research was published in the journal Physics of Fluids on March 5, 2026.

The players

Thomas Dutta

A Ph.D. candidate at Brown University who conducted the research and experiments.

Jay Tang

A physics professor at Brown University who collaborated with Dutta on the research and provided the inspiration for studying the wok problem.

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What they’re saying

“In both cases, the relevant physics involves the flow of thin layers of fluid on a surface. This physics is everywhere in our regular research as well, so we decided that this would be a nice training exercise.”

— Thomas Dutta, Ph.D. candidate (Mirage News)

“After I dump out the water from washing, there's always going to be a film of residual water. So I usually wait a few minutes to let that film of water collect in the bottom, then just dump it again.”

— Jay Tang, Physics professor (Mirage News)

“I was surprised and actually a little disappointed. I usually wait only about one or two minutes, but it turns out that I need to be a lot more patient.”

— Jay Tang, Physics professor (Mirage News)

What’s next

The researchers plan to continue studying the fluid dynamics of everyday phenomena to gain a better understanding of the underlying physics.

The takeaway

This research demonstrates how the principles of fluid mechanics can be applied to solve practical problems in the kitchen, providing useful insights that can help people be more efficient and avoid wasting resources.