WATCH: Video Explains How And Why Face Masks Function Using Schlieren Imaging

On Saturday, YouTube channel “It’s Okay To Be Smart” released a video showing how face masks work generally, and how they function as it relates to the spread of viruses like COVID-19.

Channel host and writer Joe Hanson first shows footage of a man breathing, talking, and coughing – all of which is captured using schlieren imaging, which makes certain airflow patterns visible to the human eye.

“This is how COVID-19 is spread – through air currents, potentially carrying microscopic droplets full of coronavirus,” Hanson says.

After discussing a man named Matthew Staymates, “a fluid dynamicist and mechanical engineer at the National Institute of Standards and Technology” who used the special imaging to capture the footage being showcased, Hanson jumps into the functionality of face masks.

“At 250 frames per second, it shows us exactly why masks work to slow airborne infection,” Hanson states.

Despite being unable to see actual viral particles, Hanson notes that the particles don’t travel by themselves, but “fly out in droplets of moisture,” many of which are caught by masks, thus leaving them unable to travel very far.

“And without a mask, some of those droplets can evaporate into super tiny particles of infection that can float on air currents far from your mouth or nose, and these microdroplets are extremely hard for any mask to filter out,” the host adds.

Hanson further explains that a secondary function of face masks is “that any droplets that do get through now have less momentum,” meaning they cannot “travel as far.”

As for which mask works best, Hanson says that many facial coverings have “a lot of droplet-blocking power,” but they do need to fit. A mask shouldn’t be too tight or too thick, as that could cause “more air” to shoot “out the sides.”

“A good test is to see if you can blow out a candle through your mask from about one foot away,” Hanson says.

Throughout his explanations, the host shows more schlieren footage demonstrating the effectiveness of masks.

Hanson also shows footage of an individual speaking under “laser light,” which reveals “microdroplets.” When a mask is worn by the individual, these droplets are no longer visible under the light.

Going further, Hanson cites an experiment conducted by a microbiologist who “sneezed, sang, talked, and coughed over petri dishes,” and reveals the stark difference between the masked and unmasked results.

After stating that because of asymptomatic transmission, face masks are important even for those who don’t know that they’re sick, and that it’s not true that masks lower “oxygen levels,” as demonstrated by those in the health care field, Hanson notes that masks are only one piece of the pandemic puzzle – along with distancing and hand washing.

The host pivots from the science to discuss the social meaning of wearing a facial covering, claiming that the benefits of wearing masks during the COVID-19 pandemic outweigh the unpleasant side effects like itching and fogged glasses.

Donning a mask, like wearing a prophylactic, is “a sign you want to protect others and have them protect you,” he adds.

“A mask can stop a virus, but it also sends a message: We’re all in this together,” Hanson says. “And that’s something we all need to hear right now and every day.”

There’s much more to the video than what’s described and quoted above, so you can check it out here:

In recent days, mask mandates have become a topic of debate.

On Thursday, Texas Governor Greg Abbott declared a mask mandate while COVID-19 cases in the state surge. On Friday, Tennessee Governor Bill Lee issued an executive order allowing county mayors to make decisions about masks – a move similar to that made by Arizona Governor Doug Ducey.

COVID-19 has infected over 11.3 million people worldwide, and led to more than 532,600 deaths, according to data from the Johns Hopkins Center for Systems Science and Engineering (CSSE) Global Cases map. Over 6.1 million people have recovered.

In the United States, there have been more than 2.8 million confirmed cases of COVID-19, and over 129,800 deaths. As of publication, 906,763 individuals have recovered from the virus in the U.S.