“The air in humid, hotter environments contains more water, which can condense onto the virus particles, make them bigger and theoretically fall to the ground faster. Wu compares the particles to a rock in this case — the more mass, the faster it falls.”
—-Washington Post Reporter Kasha Patel, forgetting about Galileo and gravity in an alleged science article headlined, “Covid-19 may have seasons for different temperature zones, study suggests.”
Her editors also seem to have missed 6th grade science. In truth, I believe I learned about Galileo’s experiment with the Leaning Tower of Pisa before the sixth grade, after Santa left a children’s book about “great moments in science” in my sister’s stocking. We shared it, and it ended up with me: it’s around the house somewhere. I think about the book every time I end up on Walter Reed Drive in Arlington, which is often. His story is also in it; I wish I could think of the title.
The full quote is…
Aerosol researcher and co-author Chang-Yu Wu explained that local humidity and temperature play vital roles in the size of the virus’s particles, which can influence its life span in the air. Drier atmospheres in colder regions will induce water evaporation from the particles, shrinking their size and allowing them to float in the air for longer periods. People also tend to seek shelter inside in colder environments and expose themselves to recirculated air that potentially contains the virus.
The air in humid, hotter environments contains more water, which can condense onto the virus particles, make them bigger and theoretically fall to the ground faster. Wu compares the particles to a rock in this case — the more mass, the faster it falls.
As Language Log (one of the useful website links in the right hand column of EA that almost no one sees or uses) notes, the quote by the Post raises the disturbing question of whether Chang-Yu, an alleged scientist, also is unaware of the basic scientific fact that Aristotle was wrong when he held that objects fall at a speed proportional to their mass, or the ignoramuses at the Post misrepresented Chang-Yu’s paper and his IQ as well as physics.
Other points:
- Aristotle had an excuse: he didn’t have the advantage of about 2400 years of acquired human knowledge, like the Washington Post staff does.
- This is another example of the mainstream media making readers more stupid rather than less. That’s unethical: an abuse of authority, incompetent, and irresponsible.
- The piece was published three days ago. It’s unchanged.
- Maybe nobody with a minimal scientific education reads the Post. That would be astute.
- Well, at least this episode clinched my decision whether to get a Post delivered as a replacement for the too pricey New York Times. I will not.
- The Washington Post’s motto is “Democracy dies in darkness.” Res Ipsa Loquitur.
- Interestingly, the article was in the section headed “Capital Weather Gang.” The “gang” often enlightens readers about climate change, using its pre-16th Century scientific acumen, and I see here that Kasha includes climate change among her specialties.
These are the experts we are supposed to trust, who explain the science we are supposed to follow. You know, like “the more mass, the faster it falls.“
Ethics Alarms 
OK, I am not an expert on virus particles and their behavior in the atmosphere — given their size and atmospheric effects, it could be that there are conditions that cause them to remain airborne longer.
If Wu had stopped there, it would have been ok. But a supposed scientist in any field to state that heavy rocks fall faster than lighter rocks?
Sheesh. Words fail me. I’ll bet that even my sister, who is definitely not a scientist, knows better.
The science is perfectly sound here. Particles fall due to gravity at an equal acceleration in a vacuum. However, aerosol particulars are dissolved in Earth’s atmosphere, and behave differently than in a vacuum.
Dry virus particles are supported by the atmosphere. Gravity pulls them down, but the wind blows them back up. Thus the virus particles are suspended in the atmosphere in cold regions.
In warm regions, water particles are dissolved in the atmosphere. Virus particles provide a tiny surface for water to attach to, so the water condensates onto the particles. The water saturated virus particles then fall to the ground, because the atmosphere can no longer support them. (This same principle is how rain forms in a cloud, where water clings to dust, and falls to the earth).
On the moon, virus particles would fall to the surface just as fast another other particle of mass. However, the action of the atmosphere suspends virus particles and other forms of dust and debris. Lighter particles will get blown about; heavier particles will tend to settle.
Rich in CT, agreed. Wind resistance is a huge factor here.
More mass means greater inertia and more resistance to wind. Hence, more mass will result in it falling faster. However, if his statement is one of first principles (as it appears to be), it is mind-numbingly wrong for the very reasons Jack explained.
-Jut
In atmosphere, it’s still an effect controlled by density and configuration, though, not mass, isn’t it? Otherwise, paratroopers would be having an even more difficult job 😉
At that scale, it’s not even about air resistance in they way we normally think of it (meaning: the shape of the particle isn’t really important), but more about density and buoyancy–like a helium balloon with JUST enough weight attached to the string that it won’t fall to the ground, but won’t rise up and bump the ceiling either.
In this case, sure, a moisture droplet in the air that has some viral particulate in it will be more dense and fall faster–because of its greater density and lower buoyancy, not greater mass.
BUT
It’s not even just that simple. In a hot environment, there is also the convention effect of strong sunlight heating up the ground, which in turn heats the air that comes in contact with it, forming slight updrafts. Which effect is stronger? I don’t know. It depends on the material. But I bet nearly all of you have seen the wavy lines in the air above black pavement on a hot sunny day.
I’m not going to even bother going into the issue of the Post actually printing something as ignorant as “the more mass, the faster it falls” which speaks for itself.
–Dwayne
“convection”, not “convention”
Which is why I doubt that the author of the paper used a rock analogy, and think it likely that the Post’s reporter put that junk in his metaphorical mouth.
First, I am NOT a physics major, so feel free to correct this.
However, it seems to me this statement is true given a few unspoken caveats:
1. The forces opposing that of gravity remains unchanged, or not increased greatly for the new size of the particle.
2. We are not in a vacuum.
Imagine a feather and a it’s exact duplicate made of lead. The lead feather will fall faster, even with the same amount of drag and lift acting opposite gravity as the actual feather. It’s mass counteracts the drag force through the atmosphere.
In a vacuum, they should fall at the same exact speed.
On the other hand, an unpowered 250,000 pound airplane will fall slower than a 10 pound bowling ball, because the airplane wings lift counteracts the downward pull of gravity, despite its immense mass. The bowling ball only has air drag to slow its descent.
Again, in a vacuum both would fall at the same speed.
So saying something falls faster with more mass, without the assumed caveats is incorrect.
I’m not sure the article writer cared to delve into those details, since:
1. From my reading of the article, it sounded like they made assumption number 1(since that was s the only way the article makes sense)and
2. We don’t live in a vacuum.
JutGory above has the right take. The Post says, as if it is a general principle, “the more mass, the faster it falls.” Without context, and especially using a rock as the analogy, that’s simply wrong, and outrageously so. Two identically shaped and sized rocks, one with twice the mass of the other—one hollow, one pure lead—will fall at the same rate, vacuum or not.
It’s simply a transparent ploy to explain away why Florida doesn’t seem to be having quite the same outbreak New York does, given the wide array in covid responses. “Uh… Warm moist air is really bad for germs, because they fall to the ground faster. Nothing to do with masks or shutdowns!”
Which is weird because the Post and many others en masse cited “experts” who accused Ron DeSantis of lying when he made the obvious point that there is a seasonal aspect to the virus. Whenever the humid parts of the country, Florida included, had their spikes, we got months of blather about how making masks optional was killing Floridians. And when the situation is reversed, or never places like Los Angeles were the epicenter of the whole pandemic, we get crickets, or, in this case, using Desantis’ same point, but only when it serves their political purpose.
I wonder if Kasha will report on this from the Johns Hopkins Institute for Applied Economics, “A Literature Review and Meta-Analysis of the Effects of Lockdowns on COVID-19 Mortality”
By Jonas Herby, Lars Jonung, and Steve H. Hanke
The authors’ conclusion, “While this meta-analysis concludes that lockdowns have had little to no public health effects, they have imposed enormous economic and social costs where they have been adopted. In consequence, lockdown policies are ill-founded and should be rejected as a pandemic policy
instrument.”
Fortunately, living here in humid Florida, I haven’t had to contend with lockdowns. On the other hand, I do maintain constant vigilance for those annoying, plummeting rock-like viral particles.
I agree with what everyone has been saying above. The one thing that really, really, REALLY annoys me is that either the writer, or the researcher, or both, could have gone with a paragraph explaining the subtleties we have just discussed here (no vacuum, wind resistance, etc.) Instead they went with the simplistic explanation assuming that is good enough for their audiences – that is, they think they’re dumb.
Or, if they aren’t, will soon be made so by pieces like that one…
I think it’s a fair assumption that, at this point in time, anyone who reads the Washington Post expecting scientifically accurate information is very likely a dumb person. Any WaPo writer who assumes that her readers are idiots is just playing the odds.
Likewise, I’m not sure Jack’s assertion that WaPo is making people dumber is true; anyone who trusts an organization with such a long record of disinformation and distortion is probably at the nadir of intelligence already.
As you might surmise, my opinion of this particular newspaper is not high…
Fog floats. I’m not sure any of this is actually relevant to anything, though. Outdoors UV radiation kills the virus, so whether it floats or not is sort of irrelevant. No one catches a dead virus. Indoors, air conditioning and central heaters remove humidity. An air conditioned Walmart in New York is probably going to have about the same humidity as an air conditioned Walmart in Florida. Humidity and temperature probably do have some effect on how floaty a particle is, but is it relevant or statistically significant in practical terms? Otherwise it’s just hysteria.
I don’t recall the media ever considering drag coefficients and terminal velocities for flu virus particles.
I don’t remember which grade science class I learned about Galileo’s famous experiment; it was definitely before high school. I was especially interested in the space program and the moon landings. I remember all of us sitting in front of the television when Armstrong took his first step and my mother saying, “Edward, you’re seeing history.”
Then on Apollo 15 Commander David Scott demonstrated Galileo’s findings with a hammer and a feather in the absence of an atmosphere on the moon.
I had forgotten that!