Masks and Critical Thinking - Why homemade masks really work against coronavirus #Masks4All

1 535
!!! A new video: !!!
Homemade masks are partly effective in individual protection, but they are essential for slowing the spread of the virus in the population. The main outcome of our studies was that they stop around 95-99% of viruses that people emitting by your breath, sneezing, and coughing. People are the most contagious first days without symptoms, that's why we need masks for all.
UPDATE: We have successfully tested the hypothesis at two main technical universities and it is highly recommended by a team of experts COVID CZECH under the coordination of the president of Czech Technical University in Prague. The team consists of a virologist, epidemiologist, doctors with specialization in population protection, chemists, and physicist with specialization if filtration. This group is an advisory expert group for the Czech government in Prague. Now it is obligatory to wear masks in the whole country.
Please share and help to spread the key message that can save lives and slow the pandemic.
#Masks4All: "I protect you, you protect me."
- The Chinese homemade mask tutorial:
- Another tutorial:
Scientific Studies:
- "We conclude that population-wide use of face masks could make an important contribution in delaying an influenza pandemic. Mask use also reduces the reproduction number, possibly even to levels sufficient for containing an influenza outbreak." Brienen, Nicole CJ, et al. "The effect of mask use on the spread of influenza during a pandemic." Risk Analysis: An International Journal 30.8 (2010): 1210-1218."
- "Any type of general mask use is likely to decrease viral exposure and infection risk on a population level, in spite of imperfect fit and imperfect adherence, personal respirators providing most protection." - van der Sande, M., Teunis, P., & Sabel, R. (2008). Professional and home-made face masks reduce exposure to respiratory infections among the general population. PLoS One, 3(7).
- "However, during a severe pandemic when use of face masks might be greater, pandemic transmission in households could be reduced." MacIntyre, C. R., Cauchemez, S., Dwyer, D. E., Seale, H., Cheung, P., Browne, G., ... & Ferguson, N. (2009). Face mask use and control of respiratory virus transmission in households. Emerging infectious diseases, 15(2), 233.
- Davies, A., Thompson, K. A., Giri, K., Kafatos, G., Walker, J., & Bennett, A. (2013). Testing the efficacy of homemade masks: would they protect in an influenza pandemic?. Disaster medicine and public health preparedness, 7(4), 413-418. PDF:
- Testing of masks at Brno University of Technology [in Czech]:
持续时间: 05:41


Petr Ludwig / Konec prokrastinace [CZE]
!!! A new video: !!!
Linda Liu
Linda Liu - 16 天 前
I heard the coronavirus could stay in the air for 2 days. Everyone should wear a mask during a pandemic. Protect yourself and protect others! I bought some N95 from Hope all this could finish as early as possible.
Humin Giskard
Humin Giskard - 个月 前
Thanks for your efforts.
I live in South Korea and South Koreans have realized how effective #Masks4ALL is. Especially I would like to recommend to compare the following two cases that demonstrate the power of mask.
Dr. Yu-Feng Huang
Dr. Yu-Feng Huang - 个月 前
Thank you are are hoping to do the same in Australia.
sandykelliott - 个月 前
So many different kinds of masks! One can’t really buy them now. You did not address what types, styles, patterns and fabrics are most effective.w
captainron47 - 个月 前
While I agree that a cloth mask may contain moisture droplets from talking, sneezing, or coughing. Social distancing is really the best defense. A mask comes with it's own set of issues and social distancing has seemed to be effect without using a mask. Everyone jumps on the mask bandwagon without really critical thinking the issue. Why, because it seems like the right thing to do. But is it really nessessary? There are a number of reports from good sources which indicate the mask has little to no value. These moisture droplets can enter your eyes as well, but there is no great push to for all to wear glasses with the mask. That actually would seem to be the most effective, right? Be smart and do your own research. The mask reeks of the herd mentality.
captainron47 - 个月 前
@goofball Calvin If you really look into this, doctors and nurses use masks AND eye protection. The Mask they use is a N95 or better. That is the key. Your eyes are just as venerable. But no one is telling you to wear glasses and a mask are they. It's just something to make you think you are doing something and to feel good. Wearing a simple cloth mask made from an old tee shirt is pointless. Keeping your distance from someone coughing or sneezing is your best protection. Along with washing you hands which is the number on thing to protect yourself. Don't let the goverment scare you into doing something thats not needed.
goofball Calvin
goofball Calvin - 个月 前
So mask protect doctors and nurses , but the rest of us don't need them ??
Відбірні Мемоси
Watching this because my teacher of English told me to view this video and write what it is about , lmao
Ria 8sept1988
Ria 8sept1988 - 个月 前
Ur experienced same like me.. i'm from indonesia and i work in prague.. all people were laugh at me bcs only me d one wear the mask although i feel well, just bcs i just want to protect my self of spread sneezing or coughing who not wear mask if they got sick. But its funny d end all people in czech must wear d mask when they go out by goverment command. 😂👍 ( sorry my english not so good) # just stay clean and health for ur self for stay safe 🤗
Monica Camino
Monica Camino - 个月 前
seguro, yo lo uso desde hace 20 dias, el cajero automatico es el principal foco de propagación, barbijo, alcohol en gel y toallitas desinfectantes
Owen Lee
Owen Lee - 个月 前
Stong stay together and over come the difficult time
Radical Edwards
Radical Edwards - 个月 前
Korona velki Internationalni zachranna, ale London metske policie, bez mask. Bez mask Pro proc?
Shah Ehsan ul Haq
Shah Ehsan ul Haq - 个月 前
Thanks for sharing, very useful
Vincent Kin
Vincent Kin - 个月 前
Masks are not 100% effective but they will slow down the infection rate
Albert Lovshin
Albert Lovshin - 个月 前
Ithink they finally woke up here in Canada . At first no mask as of Monday this week they are saying yes wear a mask to stop the spread . You protect me . I protect you. Keep your distancing and wash your hands.
Domingo k
Domingo k - 2 个月 前
If you don't wear masks you may spread virus
Yusif Cz
Yusif Cz - 2 个月 前
Hi from Czech Republic :D
globalman - 2 个月 前
Bravo Petr ...... You have done a wonderful thing. I will share this video.
Petr ....... why do you think the WHO officially stated that masks were not necessary for most people and only for those already infected and those who are caring for infected people??
I have lost all faith in the WHO and all such Institutions.
globalman - 2 个月 前
Critical Thinking and deductive reasoning in the USA is almost NON Existent. Alas. It has never been taught and stopped being nurtured after the 1950's. With the 1960's came the Television agenda and the dumbing down of usamericans. It has been quite successful.
The ignorance most recently is evident by the diatribe of the president and the gang of incompetents around him and how they dealt with the coming threat of the Virus.
Comparing the USA's non action to the pro active Czech Republic is seen in the statistics of infected and dead between March 22 and April 4. USA skyroceting numbers and the Czech Republic among the lowest.
Further in the USA like China the statistics cannot be trusted. The Chinese simply Lie. In the USA large numbers of people will not be counted as infected because they have no insurance and will not seek medical help. Some will also die at home in remote or rural areas and their deaths won't be known for some time and/or will be attributed to other causes and not Covid-19.
Most of the statistics are only Approximate and are in many cases far worse as no country is testing 100% of their populations.
WorldScott - 2 个月 前
Thank you Petr for helping bring about such a necessary change to helping save lives! Your work and that of the folks Jeremy Howard and Rachel Thomas made the case for your #Masks4All campaign! Thank you!!!
P Anderson
P Anderson - 2 个月 前
Sadly, this just from TIME magazine. Mandy Oaklander suggests people wear masks because they are superstitious. Please write to request it be removed. ".....Lynn Bufka, a clinical psychologist and senior director for practice, research and policy at the American Psychological Association, suspects that people are clinging to masks for the same reason they knock on wood or avoid walking under ladders."
P Anderson
P Anderson - 2 个月 前
Governments are finally coming around to this- how long into the pandemic? It is simple common sense.
MikeR - 2 个月 前
You probably will have helped to save countless lives with this advice ... I salute you and your message...and now wear a mask anytime I have to go out of my home. Masks 4 ALL. I protect protect me! Cheers from Nova Scotia.
Patrick Faith
Patrick Faith - 2 个月 前
Awesome message, great video for us in the USA.
Emily Smith
Emily Smith - 2 个月 前
Useful video! We know that when we're told it's useless to wear a mask, it is because there are no masks in shops. I home-made some masks and I also bought some masks from
1041992 - 2 个月 前
The Real Name : CCP virus , wuhan virus !
ken buie
ken buie - 2 个月 前
Rod Hoover
Rod Hoover - 2 个月 前
Great work!!
Listening Point
Listening Point - 2 个月 前
People from Czech clearly smarter than Americans.
Joe_Anroy - 个月 前
That’s why Czechs are the best country in the world. Most developed and have invented most of the things we use on a daily basis :) cheers!
MrMusiclover41 - 2 个月 前
Excellent video! I truly hope my fellow Americans will change their stance on wearing masks during this virus pandemic. I have been wearing a mask myself for several weeks when going into a public place. Thank you.
Alex Nugent
Alex Nugent - 2 个月 前
For those looking to make a mask, here is a current list of DIY face mask projects: @t
Paul Hardingham
Paul Hardingham - 2 个月 前
Great words "We are all global citizens". This is one of the great things that is coming out of this pandemic. We are all the same - we are all humans. Time for humanKIND
Exercise Caution
Exercise Caution - 2 个月 前
Let your voice heard - sign and trend the following petition #PetitionMasks4All -
Damon Mohammadbagher
Damon Mohammadbagher - 2 个月 前
thanks for really "important" information, smart People & Gov should listen to this information ...
Sir Tom
Sir Tom - 2 个月 前
The public (I mean everybody) should wear surgical masks (or similar) to protect others. Droplets can be greatly reduced in the air if everybody was wearing masks. South Korea’s Covid-19 expert Kim Woo-Jo (professor of infectious diseases) who over the last 30 years dealt with tuberculosis, AIDS, measles, SARS, swine flu, Ebola, MERS diseases says “Masks have been proven to prevent infection. In Asian countries people wear masks. In the meantime, if you look at many European countries and the US, the virus is spreading rapidly.” Watch this from 15m:51s.
Druanne Haugan
Druanne Haugan - 2 个月 前
is there a link to the info with Portuguese subtitles?
Lily White
Lily White - 2 个月 前
stevemcgowen - 2 个月 前
Most Americans won't wear masks. Even worse, most think covi is not worse than the flu...
Michal - 2 个月 前
Petře, to video je výborný počin a velmi se Vám povedlo. A už to letí světem. Hodně úspěchů přeji. 😊
Burnie Sanders
Burnie Sanders - 2 个月 前
😷The cure for Corona are governor acupuncture nipple rings 👀
Zuzana Halza
Zuzana Halza - 2 个月 前
Cuomo is Gimp 😛😂
Orlanda Guilande
Orlanda Guilande - 2 个月 前
Thank you Petr to confirm what I always thought the western countries should adopt!!!! I'm Portuguese, I'll share the word and your video here the most I can!!!
Stay home and healthy! Courage and wisdom to all the world in dealing with this and other virus!!! 🙏🏽💖💪🏼☀️
Iona Edmonstone
Iona Edmonstone - 2 个月 前
Please can you add a list of the 'scientific publications/data' that you refer to into the description section of your video.
Tom Panic
Tom Panic - 2 个月 前
It's amazing how little critical thinking there is in the world today. When the "experts" on TV say there is no point wearing masks most people just follow their advice like sheep. But the key question must be "If masks are ineffective in stopping transmission of infection then why do doctors and nurses wear them hospitals around the world???"
Well done Petr on getting people to see the other side of the argument.
Cinder Ella
Cinder Ella - 15 天 前
Dr's and nurses are exposed to a higher amount of all kinds of viruses and diseases, more than anyone on the street.
Justyna Wisniewska
Justyna Wisniewska - 个月 前
@Sara Brophy We're doing pretty fine thanks to them closing things down very early on but hopefully things won't be getting worse once they take some restrictions down, we'll see. Take care too ;)
Sara Brophy
Sara Brophy - 个月 前
Justyna Wisniewska that’s nuts about the gloves. It’s not hard to be careful with gloves! The only time I get tripped up is when I need to unlock my phone with my fingerprint to use Apple pay ... anyway, I hope you’re doing ok there x
Justyna Wisniewska
Justyna Wisniewska - 个月 前
@Sara Brophy yeah that is how they are doing it here. They introduced the masks first and now are going to loosen up other restrictions step by step.
Sara Brophy
Sara Brophy - 个月 前
Justyna Wisniewska really? Oh no. That’s terrible. I’ve been wearing masks whenever I’m out but that is not often. You do need to prep for it - I scrape my hair back so nothing tickles or irritate my face so I don’t need to touch my face. I am wondering if and when lockdown restrictions loosen up if masks are then necessary. I guess if they are touching the mask then they would be touching their face a lot too.... we have a lot to adjust!
Maker's Habitat KL
Maker's Habitat KL - 2 个月 前
Thank you for sharing the information! We are hoping to help change the public's perception and understanding of the importance of fabric masks as well. Cheers from Malaysia
Dynamite NOLA
Dynamite NOLA - 2 个月 前
You’re a global hero! You should calculate the value of reducing the viral load and getting people back to work.
Dynamite NOLA
Dynamite NOLA - 2 个月 前
Thank you!!
So many condemned me because it wasn’t n95 but I said any reduction is better!
Dynamite NOLA
Dynamite NOLA - 2 个月 前
Thank you!!!
RoyalTuxedo - 2 个月 前
It's kinda dumb how people in the west treat masks. I went grocery shopping a few days ago and wore a scarf over my mouth and nose and people were looking at me weird and the cahier who was wearing a mask, glasses, gloves and a face shield told me "I dont need to cover my face unless I have symptoms"....
Dynamite NOLA
Dynamite NOLA - 2 个月 前
RoyalTuxedo but just like that is changed! I wore my mask this week and all the clerks wanted to know how I made mine.
Rosemary Lacerda Ramos
Rosemary Lacerda Ramos - 2 个月 前
Petr, Congratulations for the video! I am Brazilian (Salvador - Ba) and we are at the beginning of the pandemic. You helped me to convince people about the importance of the mask.

I really enjoyed your video editing. I'm a teacher and I make videos for my students. Could you tell me which program you use for editing? Thanks!
N P - 2 个月 前
Eu moro na Republica Tcheca e acho incrível como é que ninguém no Brasil ( e no mundo) recomenda o uso de máscara. Aqui até os apresentadores do noticiário usam. O ritmo de infectados aqui tem diminuído. Ele tem outro vídeo sobre o uso de mascaras com legendas em Português. Procura no canal dele.
Theo James
Theo James - 2 个月 前
Prof L Axis
Prof L Axis - 2 个月 前
Jeremy Howard. Research Scientist. University SF on ABC7 news last night.
He refutes the misinformation we have been given so far.
That is to not use any type of mask in order to reduce the risk of transmission.
This is in stark contrast to best practice in the Asian countries which have much better results than The West.
Politician's egos take precedence over saving lives it seems.
UNOLIN 四城鄉事 - 2 个月 前
The latest news just came in. As of tomorrow, April 1, 2020. Taiwan will be producing 20 million surgical masks daily. (We also make other non-surgical grade masks in Taiwan, but now all people care, is the number of surgical masks.) This is not an April's Fool joke for sure. Most people in Taiwan just treat April 1 like any other day.
Matt Ender
Matt Ender - 2 个月 前
Love you guys. There is much we could learn from you.
Adriana Sabattini
Adriana Sabattini - 2 个月 前
B FP - 2 个月 前
Thank you! I hope your video will blow up in Canada.
Star's Tips & Tricks
Star's Tips & Tricks - 2 个月 前
Thank You*
Star's Tips & Tricks
Star's Tips & Tricks - 2 个月 前
please put a foto of you wearing your mask as your profile fotos
LowSocietyBand - 2 个月 前
Tasha Baddie
Tasha Baddie - 2 个月 前
Masks except from n95 or whatever the name is ( that you need training for ANDit gets difficult to breath in)DONT PROTECT.
with these other masks you still breathing the air surrounding you , bc they don’t sit tight around your face and whatever materials you will use also won’t do nothing , therefore it doesn’t work. Plus you need to be trained to use it “place it and remove it without spreading any virus” otherwise you did nothing really it will be the same as not wearing one or even worse bc you will be touching your face the most just to adjust that mask all the time.
And the way I see people Wearing them with no caution or responsibility
It’s even worse , if you was not to get the vírus now just because of that you may have . Just leave the masks alone , frontline workers need them .
Just think for a sec : Why do doctors use a full transparent face cover on top of the mask + surgical goggles ? EXACTLY .
Because that mask is just 1/3 of the full protection people.
mask in general keep the virus “ IN” to avoid spread AGAIN a good mask . Not a DIY ONE. don’t forget the spread is caused by air particles even from just talking not necessarily just caugh or sneeze
Cherriza - 2 个月 前
That's like saying the police shouldn't wear body armor because they can still get shot where they aren't protected. Some is better than none and can help slow the spread.
Red Dwarf
Red Dwarf - 2 个月 前
The founder (the money) behind is Martin Hausenblass, who owns one of Europe’s largest textile companies Alder ( and makes masks. This is a commercial.
Allen Pope
Allen Pope - 2 个月 前
Yes, big textile is trying to get us to wear masks. I can imagine the two neurons left in your brain working overtime as you typed this.
wayneboysad - 2 个月 前
I am from Hong Kong, a place very close to China and one of the most densely populated cities in the world. Our government refused to close borders to China until very recently but masks are basically de facto obligatory here and our total number of cases is relatively low (682), considering we have a population of 7000000. So I think masks certainly do help.
Ondřej Matějka
Ondřej Matějka - 个月 前
@wayneboysad We have to wear masks in Czech Republic mainly because of droplets, we new it can't filter virus if it's in air.
wayneboysad - 2 个月 前
@Traywey I think they help to a certain extent, although they can not filter the virus in the air they can still block the air droplets flying to your face when someone coughs at you.
Traywey - 2 个月 前
wayneboysad What are your thoughts on using bandanas? I don’t have money to buy masks, but I have bandanas.
Tsz Hin Chan
Tsz Hin Chan - 2 个月 前
Let's wear masks
It is good protect 👍
Add oil 💪💪💪
猴皇皮皮善 - 2 个月 前
Bombogor - 2 个月 前
Hi , ıs there any facebook frame for #Masks4All
You protect me, I protect you. I would make if i were techno savy . So I write as a suggestion .
Thank you .
Greg - 2 个月 前
Great job! I’m in the USA we need to do what you did. My son made a #Masks4All video too
dowtube1 - 2 个月 前
It seems intuitively, that a mask4all would be a great idea in breaking the chain of droplet borne transmission.
Specially when COVID-19 can be transmitted from relatively healthy infected individuals.
If the Czekhs can prove it, this would be a great advance in the fight.
MM's Post
MM's Post - 2 个月 前
Pink Pong
Pink Pong - 2 个月 前
Beyond your culture, please wear a mask to avoid droplet infection. Some people don't realize that they are infected. Because Corona virus' symptom is sometimes slight.
Jesus Gomez
Jesus Gomez - 2 个月 前
They data he cited is about influenza. Not coronavirus. It may reduce at some extent, not 100%👍
Lyssor - 2 个月 前
thats all you need and definitely better than 0%
Dynamite NOLA
Dynamite NOLA - 2 个月 前
Jesus Gomez let not perfect be the enemy of good
Andy Brice
Andy Brice - 2 个月 前
This is a reasonable point. We don't know if the SARS-CoV-2 virus behaves the same.
Wahyu Arfany
Wahyu Arfany - 2 个月 前
Thanks peter!! Thank you for sharing this! I'm Indonesian, the cases here are skty rocketing. Do you have any suggestion how to clean the mask before I reuse it. Can I just wash it? Or boil it? I don't have oven or microwave to heat it up to clean it.
Mona Elisa
Mona Elisa - 2 个月 前
@nellas1111 I haven't heard anything about that, but I guess that might work too (I'm no expert either though). Just remember that you have to also breathe through the possible detergent fumes later. So as long as you wash it well after so there's no detergent left it should be safe.
nellas1111 - 2 个月 前
I have some masks that cannot be boiled, so I put them into a (relatively concentrated) solution of detergent after coming home. After few days there, I wash them in washing machine. Any detergent or soap should destroy the virus (its coating), so I believe it works. But I do not know for sure.
Mona Elisa
Mona Elisa - 2 个月 前
For homemade masks I heard mostly: -Wash your hands before putting the mask on -Don't touch the cloth part of the mask while wearing it (touch only the straps) and if you do touch it, wash your hands right after -A 100% cotton mask (= one of the best and recommended materials to use) should be worn for a maximum of about 4 hours (before it starts to get damp from your breathing) -Remove it by only touching the straps and put in into a closed container and wash your hands after -Wash in about 90° Celsius (=194° Fahrenheit) or boil for 5-10 minutes (preferably in a pot reserved solely for boiling face masks) (Please correct me if I said anything inaccurate, I don't mean to spread any misinformation)
mobile tech
mobile tech - 2 个月 前
if you have mask from some cloth you can iron out it or boil it. and you have it disinfected
Anastasia Romanov
Anastasia Romanov - 2 个月 前
Search on CNcard to diy reusable masks
Kie 7077
Kie 7077 - 2 个月 前
Points missed in this video:
A mask is no substitute for self-isolating. Stay at home.
A mask will not stop you from contracting COVID-19, wearing a mask will reduce the chance of spread. It won't stop you contracting the virus via fomites and it will only reduce your chance of contracting coronavirus from airborne transmission. See fit-test & n95 = 95%.
Scarlet Pimpernel
Scarlet Pimpernel - 2 个月 前
The data don't support your conclusions to stay at home: the Czech Republic now (March 31) has a total of seventeen deaths. You can't give up the economy to save TEN LIVES. So wearing masks is BY FAR the most practical alternative to worldwide economic destruction.
Fleisch Berg
Fleisch Berg - 2 个月 前
There are "only" an estimated 2 billion people at home right now, thats still just a fraction. Majority of people is STILL working. What do you think where spare parts for cars, amazon orders and supermarket inventory are right now coming from? Oh, if you're dont sick and you sit at home uselessly, how about helping to save the harvest thats gonna be lost otherwise?
dean J mitchell
dean J mitchell - 2 个月 前
Sorry this is dangerous magical thinking, it’s of little use.
Amita Sharma
Amita Sharma - 2 个月 前
And your credentials for making this observation, as opposed to the virologists, filtration specialists and pandemic experts cited in the research above, on whose advice countries have lowered rates/incidence of spread after actioning the mask proposal, are ... ?
Psy Sonic
Psy Sonic - 2 个月 前
Natalie Williams
Natalie Williams - 2 个月 前
Thank you so very much, Petr!
Ra Denney
Ra Denney - 2 个月 前
My mask works well for men who have a beard.
Sandra D
Sandra D - 2 个月 前
Here in Italy we were told not to use masks in the beginning. Still so many people go out without a mask! I know it's late now but I hope wearing a mask becomes obligatory here.
lino dial
lino dial - 个月 前
Prayers for your compatriots Italy! -Lino in Michigan, USA
moltimondi - 个月 前
@Helen Peach the study is cited also by this CNN article.
moltimondi - 个月 前
@Helen Peach I double checked. It was actually 70%.. here is the study
Helen Peach
Helen Peach - 个月 前
@moltimondi where did you get this 79% statistic?
1point9and1half - 2 个月 前
@Andy Brice Not entirely, N95 and surgical masks are in short supply in the US, but the general population doesn't need what doctors and first responders need. I live in California, and at this point our State Governor is supporting the use of home made masks as this video suggests. I currently own several home made masks and believe in #Masks4all
alltheothernonesense - 2 个月 前
can you link to what are currently the best homemade designs?
alltheothernonesense - 2 个月 前
Marek Sýkora
Marek Sýkora - 2 个月 前
These are very popular:
schontasm - 2 个月 前
ode to mask
ode to mask - 2 个月 前
This is so cool - I'm so proud of you guys : ) I came to the same conclusion a bit later but from a different angle : ) congrats! Its so cool.. bunch of intuitive critical thinkers connecting the dots.. I'm sure there's a lot of us out there but wow I'm so impressed with what you achieved WELL DONE : D
UNOLIN 四城鄉事 - 2 个月 前
From Taiwan w/ love & cheers. May I introduce this video on my blog? Thank you.
Heimdall - 2 个月 前
Taiwan is the best! Good People there! Thank you for the Ventilators from Czech Rep!
Bombogor - 2 个月 前
Thank you Taiwan for best advices.
Sam - 2 个月 前
Fuck a mask I ain't no nerd
Robert Johnson
Robert Johnson - 2 个月 前
I found your video by guessing short urls
Ingrid Pufahl
Ingrid Pufahl - 2 个月 前
Thanks Peter! Your video is super important as even home-made masks can be very effective in stopping saliva from speech droplets. I just saw two new video's posted by some geeks who show that you can see these droplets with a high power laser: and that they are easily stopped with a washcloth in front of your face!
Ingrid Pufahl
Ingrid Pufahl - 2 个月 前
@Lina Bach My point exactly!
Lina Bach
Lina Bach - 2 个月 前
By some geeks!? One of those "geeks" is a novel prize winner :D
Jana Mauderova
Jana Mauderova - 2 个月 前
Sdílím kde se dá. 🙋👍🙏