Why do I always spill my coffee?

Here we go, just a short walk from the office kitchen to the desk and.... "urgh". Not again! Precious coffee coats your fingers - ouch, hot! - and maybe there are a few drips on the floor.

Why is it so easy to spill drinks while walking? Is there anything we can do to keep them in their mugs? Oxford maths PhD student Sophie Abrahams is here to explain...and show us the key to not spilling our coffee!

Subtítulos en español: Francisco Peralta, Andrea Mena, Pilar Barreiro, con la supervisión de Amalia Méndez Garrido (Facultad de Traducción y Documentación, Universidad de Salamanca).

[julyanpaul]

A significant disadvantage with the claw-grip is that, if you still misjudge your handling of the cup, the coffee overflows the rim and onto your fingers. As the coffee is likely to be at a temperature approaching that of boiling water, you are likely, therefore, not only to burn your fingers but also to drop the cup on the floor, spill the coffee everywhere, break the cup, ruin the carpet, etc. And you will have missed out on the coffee you were hoping to enjoy.

[danielhenderson]

I discovered some years ago that simply raising and lowering the mug in time with your step will keep the coffee quite still. It's like the up motion compensates for the forward sloshing and vice versa.

[giuly]

Resonance of the swing is actually obtained if you push it when it is speeding very fast at the bottom of the arc. This is because if you use your force to push it when a large distance is travelled you are doing more work, which yields a larger e increase in the total mechanical energy of the swing.

[CBMalloch]

I learned by watching diner waitfolk that putting a spoon in the mug fixes it. The sloshing coffee swirls around the spoon and the swirls damp its energy.

[johnpenner]

may i suggest the Reverse Wag? ☕️ you pitch back with the cup as you step forward, and vice versa in sync with the gait of your walk. like any music or rhythmic skill, takes a lil practice. 🍃 i also tend to cary cup with hand over the whole top to bear the cup from the above, which makes this maneuver easier than always computing the pitch relative to an up-angle when you hold it asymmetrically in front of you.

[JoeyRam.]

I got here because over all drinks one can think, Coffee is the one always spilled on tables and never cleaned up.

[creepervideo]

Always been using claw grip (before seeing this video) since ever started coffee, didn’t think it was weird but other people told me it was kind of weird but I still use it and only not when infront of guests.

[Iacca]

I walk slowly and more my feet so my movement is smooth and creates very little resonance. I will try the claw grip.

[demarcuscousinstheth]

Keeping your hand at the same level everytime works for me. Great video anyways

[TheNewPhysics]

Well... It doesn't seem like walking backward has anything to do with frequency (if the speed is the same). If you change your waking speed, that will change the frequency. It has to do with amplitude. The same goes for the change in holding the cup attitude.
So, Dr. Abrahans. You might be wrong about your analysis.

[rakshitarastogi]

Thought this would be analogy for something in life and not the scientific reason why it happens, pretty interesting and well explained video though.

[jasoncook]

So if I were to walk without rhythm it would have multiple benefits?

[rsmt]

I use the claw grip a lot.

I once had a coworker who fashioned a small wooden platform with strings attached at each corner and tied together at the top. He would carry his coffee on the platform, suspended by the strings. The resonant frequency of the resulting pendulum was, no doubt, something other than that of the coffee in the cup.

[cliverodgers]

Put a teaspoon in it. It breaks up the resonance.