The making of “Droplets”

Luke Groskin, Producer at Science Friday, joins Hari Sreenivasan to discuss the making “Droplets.”


Joining me now is 'Science Friday' video producer Luke Groskin.

This is nuts.

Just the idea that there's this much stuff inside a sneeze droplet is just cool but scary.

Yeah, we found it really straddles the line between gorgeous and terrifying.

It's this weird feeling when you're watching a sneeze at, you know, 10,000 frames per second flying, floating through the air, where you go, 'Wow, that's gorgeous.

Oh, my God, that's floating upwards.

That's a big cloud,' and it keeps going and keeps going and you're like, 'Oh, this is disturbing and beautiful.'

How do you get people to sneeze on demand for a study?

Ooh, boy.

So, if you watch the video, I'm actually in it, and it involves tickling of the nose.

The researcher, Dr. Lydia Bouroubia, she made me commit a vow of silence on the exact methodology that one uses to tickle the nose.


But her method works for me 100% of the time, but we had about a dozen grad students and, you know, post-docs in a lab trying to get themselves to sneeze.

It doesn't work all the time.

But I did it.

This is such a violent act.

There's so much force behind it.

Yeah, so, you know, Dr. Lydia Bouroubia, what she does is she tries to quantify all the different forces that are going on with a sneeze.

So, you have the actual exhalation of it, the actual force of the sneeze.

You have the buoyancy of the cloud -- this hot cloud as it drifts upwards.

You have the viscosity of the actual saliva and mucous.

You have, you know, the forces of gravity, and she actually takes formulas and actually quantifies it, and her formulas actually showed that sneezes travel way farther than you could ever possibly imagine, and it's not those big droplets you got to worry about.

It's this tiny little advecting cloud that drifts upwards into the ventilation system.

Oh, my gosh.

So, you know, we're taught to cough into our sleeves or into our elbows and use just some Kleenex, but the kind of force, it's almost like there's nothing that can stop this stuff from spreading.

Well, yeah, that's the thing.

She's just doing basic research to try to figure out, you know, what are the parameters here?

So, she has a lot of people just sneeze outward with no blocking.

And her next steps are to try to figure out how much viral load goes into each of those little droplets.

How much of those viruses actually survive?


And then after that, she's going to start to look at, you know, what happens if you block it, what happens if you muffle it?

What are the sort of measures that we can take to actually, you know, improve our ventilation systems or our own personal hygiene to improve, you know, the -- or to reduce the transmission of these diseases?

And what happens in a bathroom?

That is an entirely scary section altogether.

I mean, it just totally makes you want to -- 'Okay, I'm gonna Purell myself everywhere all the time.'

Every time, especially any sort of, you know, school or hospital.

Any place that has institutionalized toilets, one of those big, big mega flushers, you know, those things, when you watch them in slow motion and you actually visualize the droplets, and it's funny.

Nobody did this before.

It's not like somebody sat there trying to visualize the actual tiny little droplets.


You realize it's not these big trajectory droplets that you see that you're like, 'Ugh, those are gross.'

It's these tiny little invisible, fizzling, almost aerosolized droplets that are fizzling up during the flush out of the front of the toilet, and you're like, 'Oh, why?'

[ Laughs ] You can't unsee this.

You can't unsee it, and it makes you way more aware of your hygiene and also makes you question, you know, some of the practices of some of these institutions where they don't put a lid on the toilet.

It's not part of their philosophy.

So, what are the simple things we could do?

I mean, obviously put a lid on the toilet or close the lid before you flush.

That's simple.


I think there's, you know -- I don't think that the research at this stage is at a recommendation level simply because she hasn't looked at, you know, how long does, you know, a molecule or -- excuse me -- a cell of Clostridium Difficile, which is a really nasty bug that you can get in a hospital, how long does that actually survive?

I mean, she would tell you and I would tell you, and common sense says wash your hands a lot, cover your sneezes a lot, but there are a lot of, you know, things that need to be done at a hospital level that can improve -- or a clinic level to improve health, especially in third-world countries.

Yeah, I was gonna say, developing countries might not have nearly as much water or whatever.

It's the different kind of practices that you can take to prevent it in the first place.

Exactly, exactly.

How we design, you know, a ward for Ebola or for cholera or some of these diseases where you have these violent events, these violent expiration events, as they call them, and where do we put our ventilation in those situations, and how do we try to mitigate those sorts of situations?

And she's really deeply, personally invested in preventing those types of transmissions.

Luke Groskin of 'Science Friday,' thanks for joining us.

Thank you.

For more from 'Science Friday,' check out the link on our website.