SUNSCREEN in UV

How to Make Everything Video: • How to Stop the Sun fr...
Veritasium Video: • The World in UV
To learn more about CuriosityStream, go to curiositystream...
If you liked this video check out these:
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Creator: Dianna Cowern
Videography: Chris Peck, Dianna Cowern, Derek Muller and Eric Birkemeier
Editing: Jabril Ashe
Thanks to Dan Walsh, and congratulations on his PhD!
Thanks to Kyle Kitzmiller and Unicorn Snot
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Resources and Further reading:
“The Food and Drug Administration (FDA) is proposing to limit the maximum labeled SPF value for over-the-counter (OTC) sunscreen drug products to ‘‘50+.’
www.gpo.gov/fd...
NYT Article on SPF 50
www.nytimes.co...
FDA: Understanding over the counter sunscreens
www.fda.gov/dr...
Sunscreen Penetration of Human Skin and Related Keratinocyte Toxicity after Topical Application
www.karger.com...
Regulatory Policy Information for the Sunscreen Innovation Act (information on FDA’s rejection of new sunscreen ingredients)
www.fda.gov/Dr...
www.ncbi.nlm.n...
NEW SIA (sunscreen innvation act): www.fda.gov/Dr...
Schedule of sunscreen lettesr: www.fda.gov/Dr...
FDA blog safety and effectiveness data: blogs.fda.gov/...
Sunscreen + coral reefs
www.washington...
”SPF 100 vs 50 study”
www.sciencedir...
Screenshot of “health blog”
www.huffington...
Overview of suncreen ingredients
www.ncbi.nlm.n...
“Titanium dioxide and zinc oxide provide UV protection primarily via absorption of UV radiation and not through significant reflection or scattering.”
onlinelibrary....
From the FDA’s website:
“Although the protective action of sunscreen products takes place on the surface of the skin, there is evidence that at least some sunscreen active ingredients may be absorbed through the skin and enter the body”
www.fda.gov/Dr...
In 2014, the FDA updated sunscreen ingredient proposal rules
www.fda.gov/dr...

[@kfitch42]

"At the end of the day, put on sunscreen" -- uhhh wouldn't it make more sense to put it on at the beginning of the day? 😀

[@joe-zr9sq]

Here, take your *like*. You deserve it.

[@onqproductions]

Derek's throwin down some bad advice there

[@YTANDY100]

@Kevin Fitch just getting ready for the next day , hehe :-)

[@matthewread3030]

You beat me to it! Have a like.

[@piteoswaldo]

Unless you do welding work at night, it would be useless to put sunscreen at the end of the day. Happy physicsing!

[@davidjordan2336]

I have always heard the two sunscreen categories described as "chemical" and "mineral." I don't think the chemical bit is an intent at scaring people. It's just descriptive of how the sunscreen works. When in the video they say that these types of sunscreens "absorb" the UV light, what they really mean is that the UV light induces a chemical reaction within those chemicals, where they are broken down into smaller molecules. By giving energy to the chemical reaction, the light becomes less dangerous, and its frequency shifts down so that it is mostly heat rather than penetrating rays. And this is why they say you have to reapply the sunscreen every few hours: the chemicals get consumed as they work. They also get consumed if the sunscreen in left in a hot location, so it's best to not leave your tube of sunscreen out in the sun when you're at the beach. The mineral sunscreen, on the other hand, are physical barriers that are placed between the light and the skin. No chemical reaction takes place (or only a tiny one). The light simply bounces off it. This is also why you can generally see mineral sunscreens on people's skin. It's an actual physical barrier. But they also make tinted varieties that are less noticable. Both chemical and mineral sunscreen contain chemicals that are potentially toxic to some degree. The chemical sunscreens we use in the US are banned in Europe and vice versa. (But this might also just be protectionism because the chemicals in European sunscreens are produced by European companies, and the US sunscreens' are made by US companies). However, the molecules in mineral sunscreens are orders of magnitude larger than those in chemical sunscreens, and the latter get broken down into even smaller ones. So the chemicals in chemical sunscreens are much more likely to make it into your bloodstream than those from mineral sunscreens. Regarding effectiveness, my understanding is that the chemical ones tend to work somewhat better, although they need to be continuously reapplied because the UV light is constantly breaking them down. With mineral sunscreens you also have to make sure that they have BOTH zinc oxide and titanium dioxide in them, as the two minerals are effective against different light wavelengths. My personal sunscreen strategy is to use a mineral sunscreen as my every day walking about sunscreen. I mix an untinted and tinted so that it matches my skin color. If I'll have a long sun exposure, then I have a sunscreen that is primarily mineral but also contains some of the chemicals. To me that seems the best tradeoff between safety from the sunscreen vs safety from the sun.

[@Dk._]

Your comment was way more informative and helpful than this video, thank you for taking the time to explain!

[@joshaxxe7259]

which specific brands do you recommend?

[@gerrittlighthart]

The bit about American sunscreen filters being banned in Europe isn't quite right. Avobenzone isn't approved in Europe, but there is a lot of overlap in chemical UV filters approved in both the US and Europe. Homosalate, octocrylene, oxybenzone, padimate-o, ensulizole, sulisobenzone, and ecamsule are all organic filters approved for both regions, as well as the reliable inorganic filters. It might be better to say that American sunscreen formulations can't be sold easily with the same formulation and packaging in the EU due to regulatory differences, some of which are related to unapproved ingredients, but most of which come down to labeling and testing processes that are inefficient and costly. Much easier to formulate EU specific products than deal with developing and marketing the exact same product in both regions.

[@davidjordan2336]

@@gerrittlighthart Good info. Thanks.

[@davidjordan2336]

@@joshaxxe7259 I don't think I'm qualified to recommend any specific brand. I'm just some random guy on the internet who has read up on this. But I have no insight into how well the various brands are formulated. The brand I use at the moment is called SkinMedica, which is pretty expensive, but since I'm only putting it on my face and neck it doesn't make that much difference. I'd use something else if I were going to the beach (which I haven't in a while). But I chose them primarily because it seemed easier to remove at the end of the day than other brands I had tried. (Sunscreens are usually formulated to be "waterproof," presumably for use at the beach or pool, which makes them difficult to wash off). That plus they seemed to be a reasonably serious company. But this is in no way a recommendation. I have no idea how well it's actually working.

[@QyetOne]

One thing I'm surprised went unmentioned: "SPF" is defined by a testing method, where the SPF number is the threshold of how much UVA/UVB doesn't make it through the product (applied in a standardized layer). It's a very simple bit of math! SPF 4 = 1/4 or 25% of the radiation is not blocked (absorbed/reflected) SPF 8 = 1/8 or 12.5% SPF 15 = 1/15 or 6.7% SPF 30 = 1/30 or 3.3% SPF 50 = 1/50 or 2% SPF 100 = 1/100 or 1% SPF 150 = 1/150 or 0.67% So it makes good sense that you can't readily tell the difference at higher SPF's because the difference is getting tinier and tinier. The difference between SPF 15 and 30 is 3.4% radiation getting through, but the difference between 50 and 150 is only 1.3%. This is also interesting in terms of evaluating the UV camera's receptivity, because SPF doesn't discriminate between how it gets results (absorbing vs reflecting), but the camera is registering the UV radiation emitted/reflected, so as you observed absorption darkens and reflection may be invisible or actually lighter. So if you had two different brands achieving the same SPF value by different combinations of the two mechanisms, they may appear different on the camera even though they have the same efficacy from the skin's point of view.

[@baronislove3063]

Very well said.

[@fenestrapain]

QyetOne yes math!

[@rich1051414]

I was surprised it didn't look white to the UV camera, since white would be reflection of UV... Absorption would be black and would also work, in both cases the UV isn't making it to the skin.

[@__mye__8830]

so what number is best?

[@TheJetfire169]

Why so complicated? Basically Sun Protection Factor is the FACTOR how much times longer you can withstand sunlight as with your skins self protection! For example: if you can go 10min without sunscreen before you get an sunburn - with SPF 2 you can go 20min, with SPF 30 its 5h and SPF 50 its 8,33h and so on...

[@pomodorino1766]

9:39 And that's why it is important to spread scientific literacy as much as possible. Thanks Dianna for your work! (and thanks Derek also, I'm a great fan of him as well)

[@craigcorson3036]

That's only ONE of the reasons. There are MANY.

[@alveolate]

this isn't even up for debate. it is actually every govt's responsibility to make sure every child has the opportunity to be scientifically literate.

[@marcoaguilar9063]

Pomo Dorino I

[@StucklnAWell]

shame about our current Secretary of Education :(

[@Nevulas]

Isn't FDA "Food and Drug Administration" ?

[@zaesrvnge9584]

Benoît Pilet counts as a topical drug doesn't it?

[@zaesrvnge9584]

IhaveaPlaystation4 oh thank you

[@HMABH]

came down looking for this .. i got confused for a bit

[@mikejones5110]

Fda. Joke. Pushes what they are told.

[@adriandacruz9018]

I knew I'd find this comment here :)

[@AnacondaHL]

tfw you're subscribed to both channels and don't know which to watch first, so you just freeze and sit there looking at your sub box

[@doommaker4000]

Same bruh

[@acspider10]

When you are subscribed to all 3 lol

[@whuzzzup]

Both? I'm subscribed to all three of them.

[@keriezy]

Physics!

[@alex0589]

The 3 simultaneous uploads caused a great deal of anxiety here also. It's like trying to watch buffy and angel with the right timeline, we need a watching guide ;)

[@lexboegen]

I've had skin cancer (caught early, fortunately) so I'm very protective of my skin when outdoors. I prefer to use UV-blocking clothing, wide-brim hats and gloves, but I do use sunscreen sometimes. I don't want to use sunscreen often because I don't know what long-term use will do to my health. People forget that the skin is the largest organ in the body. I figure that clothes are "safer" than topically applied chemicals. I have a photo taken of me a few years back fishing from my kayak, and you cannot see any skin at all--I have 100% coverage (including my face).

[@k8lynmae]

You do know that sunscreens actually cause skin cancer right ??? they block Vitamin D which is NEEDED to prevent skin cancer and other cancers. You can also get burnt through clothes which is why some clothes are now SPF. There are many foods that when eaten or applied to the skin is a safe and natural way, rather than toxic chemicals.

[@natam5fot]

@@k8lynmae vitamin D is produced by the body via photolisis tho (you can also just get it in milk or fish) it isn't something that's just floating around so that's not really what sunscreen is doing Plus everything you put on your skin to prevent sunburn is a chemical that prevents uv light from getting to your skin be it by absorbing it or reflecting it that's who it works, if it doesn't do any of those things then you're just rubbing things on your skin for the fun of it

[@traceyannsteele]

Coconut oil monoi oil is the best keep skin moisturised to stop burning, sun cream causes cancer , u need vit d from the sun to prevent from cancer , u never hear of skin cancer in the tribal regions, because they use oils and get the vitamin d they need through the skin

[@melaninunique4364]

🤣🤣🤣😂😂😂

[@sappy.3xe]

Katelyn Not all chemicals are toxic. It isn’t fully proven that sunscreens cause cancer, though it is being investigated. And I doubt putting food on your skin is any better. The risk of cancer without sunscreen is high, better to use sunscreen- but hey, it’s your life.

[@petras01582]

I'm not so surprised that the effects of sunscreen on the environment (e.g. coral) aren't so well known. What I am surprised at is that Hawaii is going to take 3 years to ban certain sunscreens. I just don't understand what part of the ban should take so long when they know it is causing damage to the coral.

[@longpinkytoes]

Young Marshall: What advice do you have for a budding anthropologist? Dr. Aurelia Birnholz-Vazquez: So you want to be an anthropologist? Young Marshall: Yep. When I grow up, I want to go live with the gorillas, just like you did. Narrator: What she said next changed his life. Dr. Aurelia Birnholz-Vazquez: Oh, that's wonderful, but I'm afraid you can't. They'll all be dead by then.

[@sidney_wilke]

When I went on a vacation on the Cayman Islands, you musnt were sunscreen when snorkling etc.

[@christianavance9124]

Hawaii is applying a more immediate ban on the SALE of these sunscreens anywhere in the state. The 3 year timeline applies to tourists bringing them in from other states and countries. This allows time for the trickle of important news which travels at the speed of snail, while entertaining news travels faster than light.

[@busteraycan]

They are giving time for the local shops there to finish selling their stock of bad for environment sunscreens.

[@stargazer7644]

Because having a sunscreen shortage in a tropical vacation spot like Hawaii would be far worse than letting a little bit of coral die for the next couple of years.

[@fingernailclipper2152]

Woah didn’t veritasium and how to make everything make a video similar to... Oh it’s alright I saw them on... this is intentional.

[@ErinShellyMason]

Maybe it’s just because I’m ghostly pale, but I definitely have found that a higher spf is less likely to turn me into a lobster 😂 I’m going to stick to my 100+

[@monsieur.Chipmunk]

You sure does look like one, you should probably stick to 100+

[@tracywofford3384]

Higher spf is better. Spf has to do with the time it takes you to burn. So spf 100 means it woyld take you 100 times more time in the sun to burn than if you wore no protection. So keep screening and eaven double later allowing 10 minutes after each application and wear everyday. You got this!

[@ParadigmUnkn0wn]

@@tracywofford3384 SPF is based on the amount of UV radiation that gets through a layer applied using a standardized method and resulting thickness; it's a lab test using analytical equipment. It's also a logarithmic scale, so SPF 100 does *not* provide double the protection of SPF 50. SPF 25 = 1/25 or 4% of UV light passed SPF 50 = 1/50 or 2% SPF 100 = 1/100 or 1% SPF 150 = 1/150 or 0.67%

[@rsmith02]

Try a good quality zinc/titanium sunscreen. You should not turn into a lobster even with an SPF of 30. Check out EWG's ratings re: toxicity and UV effectiveness.

[@ErinShellyMason]

@@rsmith02 I’ll have to try that out, I’ve had some bad sunburns in my lifetime so whatever works is a lifesaver for me! Haha

[@baconcassoulet849]

The perks of SPF 50+ is that in France the UVA protection has to be at least 1/3 of the SPF, so between SPF 30 and SPF 50+ the UVA protection is really different !

[@theomnivert]

I like that there wasn't a single mention that they're doing a collaboration While still doing it WOW

[@Kraigon42]

"Ladies and gentlemen of the class of '97: Wear sunscreen. If I could offer you only one tip for the future, sunscreen would be it. The long-term benefits of sunscreen have been proved by scientists, whereas the rest of my advice has no basis more reliable than my own meandering experience."

[@Ghazala_Aizal]

Can we use sesame oil as sunscreen?

[@sab-ali]

Every time i put sunscreen, i hear this in my head.

[@bumblebii2225]

@@Ghazala_Aizal what? Bro sesame oil is not spf, just wear spf

[@Broadpaw_Fox]

"I will dispense this advice...now". :)

[@fonkenful]

Golden oldie as far as the interwebs are concerned.

[@JcGross93]

When strictly speaking about the camera method of checking the UV protection you have to keep in mind that the absorbing sunscreen absorbs TWICE. This is something that you didn't adress in the video, I don't know if you've factored this in. But essentially the sunscreen lets through a small part of the UV light and absorbs the rest, and when it reaches your skin again some part is reflected and absorbed. When you get to factor 50+ it becomes hard to tell from a camera if the light had been absorbed once or twice (meaning maybe the 100 factor sunscreen absorbed almost all of the UV light the first time around, and the 50 factor one only absorbed some first, and some more on it's way back). I hope I'm being clear in what I say, I'd be interested to hear back if you factored this in.

[@timwcronin]

Retina vs tapetum lucidum

[@anonnymouse2402]

If you absorb the UV the energy does not go away, it is just transferred. As some of the chemicals used have a photocatalytic effect, the energy absorbed can sometimes do more damage to cells than the raw UV. Zinc oxide based sunscreens are the lowest risk based on current knowledge, but the best option is to stay out of the sun where possible.

[@robertowens6674]

Enjoyed this, and I love Physics Girl and Veritasium, but I'm a bit disappointed they didn't mention sunscreen should be the last line off defense. Most dermatologists say to wear sunscreen, but also to use shade and protective clothing (hat, swim shirt etc) as your first lines of defense against the sun.

[@NaveedAhmedWaghani]

Love you Physics Girl!! Please get well soon! ❤💐

[@jg7736]

The spf number doesn't mean that the suncreen is strong per se, but it will protect you from the sun for longer.

[@mohamadeen]

Veritasium and the tumbnails matched in my subbox D:

[@jardelelias5625]

I happened here too. At first glance i was like "wait, what?" haha

[@MaxOakland]

I think it’s interesting that most sunscreen absorbs UV instead of reflecting it

[@islander4986]

I believe UV light exposure is also how the body makes non-dietary vitamin D, so moderate UV exposure can be considered to be healthy. Glad you mention that many sunscreen ingredients have unknown properties/effects on the human biology, and known detrimental effects on marine life. As far as I know, old school zinc oxide is not unhealthy to us or corals.

[@asmahaque8558]

The graph for effectiveness of spf is not linear. Which means that while SPF 100 is better than spf 50, the difference between them is still lesser than that of between spf 10 and 50

[@TheExpeditionUK]

widespread sunscreen use has coincided with increased melanoma, research has suggested that sunscreen is bad because it blocks uvb well, but not uva, and it's the uvb that has a protective effect, see University of California-San Diego.

[@joermnyc]

I think the zinc and titanium are better since it’s reflecting the UV away... somehow that makes more sense than absorbing it into a film that’s sitting on your skin.

[@billcornelius1383]

many insects see uv (also shrimp for some reason), and flowers have special patterns that show up in uv to direct pollinators to their nectar. butterflies raised in cages can find artificial nectar if it's in conjunction with some kind of uv reflecting item, like plastic beads. The moral here is if you collect butterflies and don't want to be seen, :) some sunscreen might help.

[@frederickdyson-fereday553]

Yay, two favourite KZbin Derek and physics girl

[@TheDisneylover23]

The number is supposed to indicate how often you need to reapply it.

[@thedownwardmachine]

Simple chemicals (usually inorganic) have mostly been known to science for quite a while and their effects on people are usually fairly well characterized. Complex chemicals, usually organic and especially new ones synthesized in a lab or derived from exotic plants, tend to not have their effects on people known, which does not mean they are dangerous, but it does mean that if they are dangerous then you might spend decades using it before you find out, and by then it's too late.

[@gwynt909]

My brother lived in Cairns in Oz from 1979 to 2013 and was religious in putting heavy duty sunscreen on every single day. And he died in 2013 from melanoma - skin cancer.

[@Bibblesupremacy1992]

If you get constant sans exposure every day it’s bound to happen

[@steveshea6148]

I've read that polycarbonate (e.g. Lexan), which essentially blocks almost 100 percent of the nonvisible spectrum, absorbs uv energy, in the process creating a reverse chemical reaction which degrades the polycarbonate back to its bisphonol-a and, presumably, phosphene gas, constituent components. I'm not sure how efficient this reaction is in decomposing the polycarbonate.

[@anakarmelalopez7962]

Mostly, it is about concentrations. Yes, the dosage is important. But if a person is in the water it washes off. Also, people with more melanin and less melanin have different absorptive mechanisms. I am not so sure about the bleaching effect on corals if it kills the cells, that is most likely also being used for disinfection, used on cosmetics as preservative and just so people do not have skin infections afterwards or products do not expire easily. The place of manufacture is also important. And people should read the details on the labels. It will also depend on the UV concentrations in areas where these sunscreens are used. And also the person's diet, health conditions, etc. Either way...everything too much is not so good. With or without sunscreens.

[@thedon1262]

You are so handsome and smart diana! Thanks for making these videos ^^

[@yzScott]

Seems like looking at the transmission of UV through glass treated with sunscreen would work all the time.

[@robertfournier7050]

2018. That means we have six years to catch up with you. UV light well give a little thought to snow. What happens with bright sunny light on snow deflects the light. That brings up a whole bunch of ideas.

[@misterglod8893]

I love her and i love you veritassium!

[@worldtraveler930]

So what are we talking about? Is the actress who was painted gold in "007 Goldfinger" had she the best of all sunscreens???

[@arrtea]

I thought sunscreens reflected uv light🤔🤔🤔

[@ParkerAnderson1]

A K yeah me too! It was so cool too see how it really works

[@arrtea]

Parker Anderson Yes .. very cool👌

[@joussefabouali4795]

Sorry I am late, but there is a brand called Bioderma with 100+ SPF rating. I have to always put on sunscreen due to my sensitive skin and I used many different brand in the past years. I have found out that it usually depends on which brand to trust, not the rating(I am not a scientist), but usually a 50 SPF in a brand is sometimes not as good as another.However, when I tried Bioderma there is a huge difference than putting on 50 SPF with other brands. I personally tries putting the 100 SPF with another 50 SPF spray sunscreen, and I was totally burned in the areas where I had the 50 SPF, but I had minimal burns in the areas with 100 SPF Bioderma.

[@ryang256]

Higher SPF sunscreens come into play when considering length of protection. SPF 100 and SPF 50 sunscreens offer nearly identical protection when first applied. However after an hour of swimming the protection from the SPF50 will be significantly diminished where as the SPF 100 will not have lost nearly as much.

[@dwellspompano]

Thank you for the great video. I'm still a little confused about UV absorbtion vs reflection. I would think reflection for sunscreen would be best. Why would you want to absorb the UV ? Or is it the sunscreen absorbs the UV instead of your skin absorbing it?

[@SharonPorts]

One thing they forgot to talk about was UVA and UVB rays. The sun protection that protects us from BURNING ( UVB) reflects. The sun protection that protects us from AGING (UVA) absorbers. Using a sunblock that has both of these is called BROAD SPECTRUM. You will want both because one will save you from burning and the other will protect you from aging. The UVA rays go farther into the dermis breaking up collagen, elastin,other important molecules and damage your DNA. This is why you age fast in the sun over time.

[@Lotuseater1990]

Same question from India 🇮🇳

[@angelinakodjabashia7416]

Sunscreen absorbs the UV and converts it to heat energy, the effects are not noticeable, you won’t feel your face heat up, the heat dissipates.

[@MrPDawes]

I think you need to distinguish between UVA and UVB. We need UVB to synthesis Vitamin D which right now is very important for our bodies immune system in combatting Covid and other diseases. This is why during Winter and people who spend all their time inside like people in care homes don't get the UVB they need to produce Vitamin D and have been the hardest hit during this pandemic. We need sun block which blocks only UVA.

[@TacDyne]

Skin cancer cases diagnosed in Australia in 2021: 16,878 In Argentina? A little over 1.000. In Indonesia? 1,900 give or take a handful. In Germany? 31,468 cases. In the US? 331,091 cases, Yeah, that's a good case for sunscreen cause and effect. it's also a good case for eugenics too, considering the whiter the population, the higher the skin cancer rates are.

[@nehaparmar3544]

Sunscreen is imp for sure .. but exposure to sun is important too to heal certain diseases..so pls don’t fear it so much

[@ladyn24]

FDA is food and drug administration not federal drug administration. Any spf above spf 60 has the same effect as spf 60 but it lasts little longer or protects little longer thats the only difference. So its not the efficacy it's the length of protection.

[@cocococo9752]

Soooo satisfying..

[@theshinyskuntank5955]

Now this is a near foolproof way to check if you missed a spot!

[@michimelody4036]

Spf does not have anything to do with how strong the sunscreen is. It's how frequently you're supposed to reapply the sunscreen. It's meant to be how long your skin takes to burn without anything on it times the number on the bottle is how long you're supposed to reapply the product. It has absolutely nothing to do with the actual strength of the lotion. So therefore anything over the spf 50 is pointless because you're supposed to reapply after that point normally anyway..... PLEASE PLEASE PLEASE pay attention to this comment! The companies trained us about this while i was a beauty advisor at Walgreens.

[@deyaniscamarena3707]

Sunscreens only reach up to 50 +++ spf, more than that they are just commercial numbers. And you could not choose the worst brand of sunscreen

[@MikaelMattsson-h8l]

If you wanted to judge the reflective and absorbent sunscreen in a similar way, could you not have put it on a transparent surface and looked how much UV went through. Both would be dark on the "back", right?

[@marcmacd2706]

Loved this video!

[@MYtimeNspace]

I am an electronic engineer of 45 years. Watching your videos it seamed strange to me that no one said anything about black body absorption of the radiation, The UV energy even though the sunscreen may not be letting the UV through is it causing the energy to be converted to lower frequencies of energy say IR, and heating the skin and basically cooking the skin ??? The energy has to go some where. Seems to me you need to do full spectrum transmissive test not just reflective testing. I would love to see those results.

[@princenephron7546]

8:15 - Ehhhhhh, technically, Helium is NOT a chemical, because it is monoatomic. There are no "chemical" bonds. It's an element. It's an atom. It is NOT a chemical.

[@sto-humanfriendly]

a chemical is any substance consisting of matter are you thinking of compounds???

[@culwin]

The long term benefits of sunscreen have been proved by scientists. Whereas the rest of my advice has no basis more reliable than my own meandering experience.

[@samara4367]

[@k8lynmae]

And your sources ?? Sunscreens ARE a SCAM and actually cause cancers as the chemicals in MOST sunscreens BLOCK Vitamin D which is NEEDED to help prevent cancers. Not to mention the chemicals entering our blood supply ... There ARE SAFE and NATURAL ways to prevent sunburn and block the UV rays

[@andresvillanueva5421]

@@k8lynmae Vitamin D? You can get it from food. That's not a problem.

[@andresvillanueva5421]

@@delve_ Oh, thanks for the info!

[@vacafuega]

@@andresvillanueva5421 A quick addendum to say that you cannot actually get enough vitamin D from food alone. I found this out when I became severely deficient last winter, and the doctor laughed when I told her I eat a lot of eggs and fish. If you live in a northern hemisphere country and you don't get much sun or take a supplement, you are probably deficient to some degree, which is a big deal since vit D is involved in so many of the body's essential processes.

[@trulsdirio]

I don't even care about skin cancer, just avoiding the short term pain of a sun burn is enough for me to make me use sunscreen.

[@Sytanya]

is it only me, or are these two the perfect couple? :)

[@LungsOutJem]

Blackface isn't offensive if it's for *SCIENCE!*

[@mohammadrafiq2899]

Your chemistry is best....

[@prithvirajdj]

Ok. Isn't it *common sense* go take off your footwear before sitting on that couch?

[@ayasongpizza8197]

the backround music is giving me persona5 vibes

[@dennis4248]

03:18 - Yes :-D But it also looks like face paint in visible light :-D

[@dr.delacruz-balagotbalagot8934]

still watching this in 2020. anybody?

[@HappyfoxBiz]

Chemicals.... The word has been demonised for quite some time, and still is today, my suggestion to people is do your own research on it, for example fibre glass is deadly to you in some circumstances such as skin irritation and lung damage, can cause blindness and so forth if handled inappropriately but... If handled appropriately it is safe as insulation, strong in bridges, is great as a strong replacement for plastics when it comes to corrugated boards that you use for your patio and pergola, it can be put into concrete to increase the strength making it so that instead of big rigs ripping up the road it flexes and returns to the original shape unlike asphalt which tends to go brittle or sag into potholes and unlike asbestos is not a huge risk when mishandled. The same with spray foam and many other chemicals, but ffs understand that with H2O it tends to kill a lot of people as well as keep them alive, people need to understand dangers, they aren't putting mercury and lead into sunscreen, and for the antivaxxers, ffs vaccinate your kid before I sneeze on them, if they are years old they are middle age.

[@OneFlyingEye]

You really need a biology person on your team for stuff like this, I've got a degree and willing to travel ;)

[@E60N]

Even if some sunscreen are harmful they're not nearly as harmful as cancer

[@bnicely1779]

I am a welder/fabricator. It would be interesting to see the UV from the MIG welding process.

[@unddxchjnuisseedxgi6ideexc604]

i see there isnt much different of physical and chemical sunscreen. they both are good

[@afrost8516]

The physics girl is so good she makes vsauce look silly 🤭

[@cipherxen2]

Thumbnail - Diana : battle Angel

[@crazylegoman]

It's not the best choice of words to say, "At the end of the day, wear sunscreen."

[@marianamohammed605]

this is sooo informative!

[@Das_Beachy]

Can't remember which brand it was but I found a sunscreen I was allergic to as a kid. I would start itching and sometimes get hives within a couple hours of application. We thought it was a chlorine allergy because the symptoms would start after going swimming at the neighborhood pool so my parents would have me shower in the locker room at the pool before leaving. We realized it was the sunscreen after the same symptoms appear when we went to an airshow and I put on sunscreen. My parents took me to a dermatologist who recommended Coppertone Sport. Used that ever since.

[@amyarmbruster8313]

I Luv physics

[@Heyitspat]

Chemical sunscreen really make it feel 'toxic' to the common public. But naming it Organic sunscreen, which really means the same chemical carbon based sunscreen, just all of a sudden makes it feel so much "healthier". This is the entire issue i have with the organic, chemical = less healthy perception.

[@lyngirasol5773]

I was told ...don't use anything under 60 or it's not worth it...but I'm Irish/ German...so maybe based on heritage is different to everyone

[@oagid]

Havaianas flip flops! ^^

[@meetrii]

Invisible melanin interesting

[@masterminstrel]

What would've been cool is if you'd filmed in UV the affects of going in water with sunscreen on, or maybe a time lapse to show how much it fades throughout the day.

[@Mystixor]

True, having a camera setup like this is just so amazing

[@rosepinkskyblue]

Yes definitely I need to know if we really need to reapply even when we’ve been indoors 🥲

[@adriennemiller.music.]

but not in natural water

[@peterjobrien]

Almost nothing in this video made use of the UV camera and we learned almost nothing from the UV camera shots apart from the obvious. I kept waiting for the timelapse or... something. I guess they ran out of time spraying the van.

[@Luke-es2ej]

@@peterjobrien If you watch the How to make everything video in the description they do a lot more of what you're talking about

[@veritasium]

I love how on the day we filmed this I got sunburned because I couldn't wear sunscreen or else it would show in the UV camera. I like that my stealth filming of you telling us how you really feel made it into this video. Also, why do I look so serious? Happy Physicsing Dianna!!

[@ajayrawat9317]

You guys uploaded your videos at the same time

[@leonidizakov1189]

+AJAY RAWAT For me there was a few minutes of delay on this video, I wonder why?

[@JustYaeWendt]

Possibly because the current UVC, B and A rays have been setting at extreme levels for quite some time now..

[@GlenHunt]

Your cancerous demise isn't for naught, my friend. Your sacrifice is for the greater good.

[@RomanoPRODUCTION]

Leonid Izakov, testing KZbin notification system maybe ?

[@jefferylegere]

I had a discussion not long ago where I was in favor of including UV cameras in cell phones for creative purposes and others saw no benefit to having them. This would be a great use for them, you could see if you had applied your sunscreen properly.

[@kg4boj]

Sony handicams with nightshot mode had that feature, as it turns out they see right through many clothing articles and the tan through clothes are as transparent as saran wrap!

[@InservioLetum]

except that much of our "invisible" tech operates entirely on the premise that humans cannot discern UVA or B over visible light from the same source.

[@MissMoontree]

It would be super nice to be able to use a selfie for that

[@mars2101]

frr i need this

[@vadnegru]

Maybe useful as an add-on, like flir camera

[@physicsgirl]

OH MAH GARSH. Benoît, you are very correct. FDA stand for Food and Drug administration. Apologies for the error, all.

[@spiritusinfinitus]

You might want to look up common vulgar British English usage of the last word of the first sentence there! ;)

[@dentoncrimescene]

Lol.

[@Lost_isle]

better heart your comment to stay pinned

[@raztubes]

I'd really go with GOSH there. Trust me on this one :)

[@xredskaterstar]

Just curious, how well can you trust a federal program such as the fda with all the controversy of these programs being paid off by big companies? Also you remind me of Denise Austin in her younger days when you were sitting on the couch.

[@davidmaes3253]

At 10:28 Derek says "At the end of the day, put on the sunscreen". Bad advice. I would put it on at the beginning of the day. :-D

[@artdeco777]

Copied.

[@lindsayguillen7]

I think he meant something like "but over all, you really should be putting on sunscreen" but good pointing that out !

[@daledo8604]

@@lindsayguillen7 r/woosh

[@jonnyjazzz]

Best Comment.

[@topdawg4854]

Ayyyeee

[@user-dz2hj6jo5h]

Can’t help but sing “THE SUN IS A DEADLY LASER”

[@BosonCollider]

(after applying sunscreen) NOT ANYMORE THERE"S A BLANKET!

[@kdiamroyal06]

Sun is for superior ppl it’s natural energy unlike man made light. It goes to show u why blacks are hated I never knew THE SUN DESTROY NON BLACKS that’s crazy it gives me energy everyday especially coming out these cold buildings. I understand why they keep trying to block out the sun lol bc of vengeance lol

[@kdiamroyal06]

Obscurianus my whole family sun gaze not no one family ever was scorn no skin cancer my melanin protects us that’s why we were able to build in spaghetti with no hats nor sun block all we needed was food n water MELANIN IS WORTH N COST MORE THAN GOLD DIAMONDS OR ANY RUBIES I KNOW MYSELF

[@kdiamroyal06]

Obscurianus nothing lives in winter no plants grass etc my hair grows up towards the sun ☀️ Because it gives melaninated people LIFE that’s why our hair texture is different from any other nation it doesn’t go downward like animal hair but Up in Afro manner only looking for the sun n waiting on water...

[@jarosawpe4353]

No, it's not a laser.

[@Hepcat83]

There’s a plant called Heracleum, which is pretty common in Russia (and the whole northern hemisphere if the Wikipedia is correct). It’s very invasive and grows very fast. If not destroyed it can cover very large areas very fast. What’s worse is that its juice causes severe burns. That’s common knowledge in Russia. A much less known fact is that those burns are not caused by juice itself. These are actually sunburns. The plant’s juice causes chemical reaction which dramatically increases skin’s photosensitivity. So it’s basically a reverse sunscreen. And those severe (sometimes even lethal) burns can be avoided just by covering from sunlight.

[@loading1345]

Hepcat83 woahhhhh

[@Cyruscosmo]

Wow... That is my interesting fact of the day. Thank You HepCat83!

[@Anbuhiro]

hah.. that's interesting. the more you know...

[@koyaaanisquatsi]

борщевик?

[@Hepcat83]

Toma да

[@Ema-fm5zy]

I don't get why people think inorganic is bad and organic is good. Poison can be organic as you can get it from snakes, scorpions and animals like that. Water is inorganic, air is inorganic. People really nead to understand what can do damage, to who and in what quantity. It's like I'd be against using peanuts for any purpose because some people are allergic.

[@almarma]

I have a theory: First, most people are not interested in science at all, so the interest / knowledge about chemistry is very limited. The second factor is the BIG MISTAKES the chemistry industry has made in the past. Maybe young people have not experienced it but I'm 43 and I remember huge mistakes made by them during my life: - DDT - The CFCs and the Ozone depletion - Pregnant women taking some medicines and children developing illnesses or deformations. Also the greedy tactics some big companies like Monsanto or Bayer against Third World countries or against farmers, damage the reputation of anything labeled as "chemical".

[@PapaKlimentino]

Need*

[@jfj876]

Loooool

[@chevychase3103]

Human bite would be organic but full of bacteria!

[@chevychase3103]

@@almarma the theory that GMOs are safe! Not they're designed to absorb chemicals like Roundup! So we absorb those chemicals!

[@TyBraek]

I was super surprised at the spray sunscreen. I always thought they feel like they cover, but aren't covering as well as normal lotion.

[@fortusvictus8297]

Spray sunscreens are necessarily easier to wash/rub off of the skin, so they seem to be worse at protecting over a given period of time (I apply in the morning, lunch, and after about 3pm). If they were 'stickier' or thicker they wouldn't spray very well at all...and they already have an ick factor that most salves and lotions don't have.

[@htme]

Thanks for helping us with our experiment and trying on the sunscreens, it was a blast!

[@PlaybyPlay225_2.0]

I was wondering, exactly what camera did you use for the UV?

[@RenTheGreat]

@@PlaybyPlay225_2.0 you can use any camera. You just have to take the UV filter off

[@sivadurgasri9446]

Can't understand...is it good to use sunscreens or not

[@beingme._.eilonwy4571]

@@sivadurgasri9446 You absolutely need to use sunscreen.

[@arianne6404]

Uhmm I think FDA stands for “food and drug administration” not “federal drug administration” 4:56 I love the video though❤️

[@Tribul936]

Disappointed that no distinction was made between UVA and UVB.

[@catherinej4369]

the distinction is UVA will stop at the Ozone layer and get reflected, UVB has shorter wavelengths so its UV will pass through clouds and come in contact with our skin causing skin cancer and eye damage. But, note that the most distinct thing between them is if we didnt have the Ozone layer, UVC could get through and is the most harmful and can damage our inner layers and theres nothing a bit of sunscreen can do about it. Hence we really should prevent global warming.

[@angelvelasquez2381]

@@catherinej4369 you are thinking of UVC not UVA

[@Kamlloki]

catherine j UVC is stopped at the ozone layer. Around 95% of UVA will hit the earths surface.

[@AnhLe-zl4ws]

catherine j UVA does come in through the ozone layer. UVA causes aging and skin cancer because it affects deeper layers of the dermis whereas UVB affects tanning and burning. Also the SPF rating only takes into account UVB protection and not UVA protection.

[@Madithemuggle]

Also Zinc Oxide is the only reliable sunscreen ingredient that protects against UVA rays effectively, which is why I always opt for mineral sunscreens, or combo sunscreens.

[@noisy99_]

how to be a toxic person: Use reflective sunscreens, persuade your friends not to wear one, and give your friends skin cancer

[@es5398]

Reflective sunscreen are safe! Zinc oxide and titanium dioxide are the main ingredients of physical sunscreen

[@lambgaming1347]

@@es5398 The joke is that your sunscreen will reflect off you and onto your friends who aren't wearing sunscreen..

[@es5398]

@@lambgaming1347 it’s doesn’t work like that hun! 😂

[@lambgaming1347]

@@es5398 That's not the point... doesn't matter if it actually works, its a joke.

[@aname3116]

Actually that’s a myth, most of the uv light is absorbed by both mineral and chemical sunscreen, and the information in the video is slightly outdated/now proved to be wrong. I’D recommend for example Dr Dray’s channel, she’s a dermatolologist and she talked about it a few times. There is a lot of contadictory info online now btw

[@Mr._Du]

the best sunscreen is staying inside to watch physics girl and veritasium videos all day

[@ianscott947]

He means being a hermit.

[@Amberzit]

You'd also need to stay away from windows, as UV-A radiation goes through glass (and some textiles), and is actually pretty dangerous. But you'd probably do that anyway, otherwise you can't see your screen properly!

[@ryantan8666]

Will probably die from heart disease instead of skin cancer

[@patrickmccurry1563]

It is possible to exercise at night, assuming you're equating going outside during the bright daytime with sedentary lifestyles.

[@Skeptical_Numbat]

And end up with low Vitamin D levels... I live in the South-West of Western Australia, where we used to get the hole in the ozone layer move overhead during summer (40°C+ temperatures). You couldn't wear enough sunscreen to prevent long-term skin damage & tens of thousands of people ended up getting skin cancer. The social impact was huge, with massive government campaigns to indoctrinate kids into using waterproof sunscreen & protective clothing ("Slip, Slop, Slap"). Now, the current generation of parents are so paranoid that they would wrap their children in lead foil if they thought that it would help prevent cumulative skin damage & cancer.

[@coreywild]

WOW where di you find all these people who are actually interested in learning something!!?? Well done!! Nature is AWESOME cool Vid!!

[@mishkabaloo1447]

It is natural for people to be curious! So no wonder to that. Actually I believe that curiosity is been killed in the most schools. Because in school they provide all the answers, even before you ask them. But it kills curiosity

[@TheJerbol]

What an utterly strange question

[@Rubiecat]

are you under the impression that you're the only person who likes to learn things ?? what an ego...

[@NewMessage]

SPF is also the noise you make when you accidentally open your mouth when spraying sunscreen on your face.

[@GIR177]

While i know this is a joke, the label literally tells you to spray it on your hands, and then apply it. It's people's own fault.

[@101be8]

HAHAHAHAHA

[@danielfogli1760]

🤣🤣🤣🤣

[@perfectfae3534]

I need a camera like this, so I can see if I put my sunscreen on correctly.

[@utbigpapa]

11 months later.. there is a product call Sunscreenr that connects to your smart phone. We have one. It works. No more zebra stripes 😂

[@bellaknightR597]

Same, I'm sooo pale and burn so bad that I can't miss a spot

[@giselleo5976]

@@utbigpapa where did you get yours! I can't find it online anymore and the ones on the market emit a hella harsh uv light which completely defeats the purpose

[@MeepMeep88]

Thanks, now I know which sunscreen to get.. Sharpie

[@gracygeorge7506]

thats what i thought too !!

[@forgy_man311]

Candi Soda yup !

[@Amelia-rs7qv]

Why is your pfp a clown

[@vikj1255]

a bandage ;-)

[@deeperlayer]

a better test for "physical" and "chemical" a piece of uv transparent glass coated with different sunscreens with uv source behind it and camera infront to see how much uv passes through

[@djcg]

yes, this is what i want to know! great idea!

[@ujjwalbansal3246]

It would be a good way to compare reflective and absorbent type sunscreens too

[@deeperlayer]

Ujjwal Bansal yea its much better since reflective type could simply be not working no way to know using their method

[@The757packerfan]

I agree. And it's pretty ridiculous that this experiment wasn't done in this video. The quality of her videos has gone down a lot as she no longer gets into the weeds and just stays on the surface.

[@jeffroberts3136]

Did you try smearing sunscreens on a clear filter and putting it in front of the camera lens? This seems like a better test of sunscreen effectiveness since reduced transmission is really what you want to test regardless of the cause be it, reflection or absorption. Sorry if this has already been proposed in the 2 years it took me to find this video. Love your channel!

[@georgeelgin3903]

The optic's involved is like trying to measure radiation through a mirror.. retina's are trained to respond to visible light pupils limit amplitude cones to spectrum and rods to intensity

[@GeekProdigyGuy]

@@georgeelgin3903 it's a UV camera.

[@sshum00]

It's as bad as when people say they don't eat chemicals.

[@MobiusPeverell]

God, that's bad. Specificity is a virtue.

[@stevethecatcouch6532]

Most chemicals are fine. I just quit eating metals. My food tastes very bland and my nerves are having trouble firing.

[@ethanpoole3443]

Yep, no chemicals in my body - nor any molecules or even elements. I’m pure spirit and imagination. So it must be true. :-)

[@WouterCloetens]

Ethan Poole That was a vacuous comment. ;-)

[@adamgh0]

I just want to know what happens if you spray sunscreen on a solar panel. Would it still work as well?

[@dakotadawn5789]

Good question

[@rosscameron6585]

I found this.... "Sunlight energy that reaches the ground is around 4% ultraviolet, 43% visible light, and 53% infrared. Solar panels mostly convert visible light into electrical energy, and they also can make use of almost half the infrared energy. But solar panels only use a small portion of ultraviolet." If by "small portion" they mean "somewhere less than 50%", then an SPF100 sunscreen on a solar panel would decrease its' available total energy by less than 2%. Obviously the sunscreen would not absorb into the solar panel, like it does your skin; so you'd end up with a visible film over the panel, which would also block a small amount of visible light. Conclusion: You can stop your solar panels from getting sunburned if you're prepared to lose

[@Rickmakes]

Spray sunscreen doesn’t seem to make much sense because you are essentially protecting your skin at the expense of your lungs.

[@richardsandwell2285]

It is all toxic and should not be on your skin. I even avoid shower gels, I actually manufacture my own bar soap so that it does not have unnecessary chemicals in it. Sunlight in sensible amounts leading to a full tan is healthy for us, that was proven years ago by proper scientists who were not bribed to say one thing or another.

[@Veda7ate9]

@@richardsandwell2285 b did you watch the video

[@richardsandwell2285]

Yes.

[@eleob9098]

There are safe sunscreens, it just takes a lot of searching lol. Zinc oxide seems to be generally safe

[@samara4367]

They've also been known to make people freakin BLIND (mostly children) which is horrifying.

[@Blackmark52]

3:55 Dianna is making a mistake here not acknowledging gamma compression in grey scale values. Our eyes just aren't made to distinguish linear value changes so that part of the scale gets compressed. Just because it LOOKS like there's not much difference between 50 and 100 doesn't mean that the 100 isn't ACTUALLY twice as dark.

[@m.c.v.a.8586]

Blackmark52 wow I had no idea about this, I hope she sees this comment

[@patrickmccurry1563]

It's the entire reason for so much false color in fields like astronomy. It lets us see so much more detail we would otherwise miss.

[@oliverwilson11]

no the brigher parts get compressed more

[@Alex-ki1yr]

+

[@Blackmark52]

oliverwilson11 "the brigher parts get compressed more" Maybe it's a matter of which way we're looking at it. The point is that our eyes are less sensitive to linear changes in the dark end and more sensitive in the light end. kzbin.info/www/bejne/jXvdnpaAhqufl9E