SUNSCREEN in UV

abroad for supporting PBS Digital Studios. Wow, it looks like I'm using really bad tanning oil. Hey, it's Diana, you're watching physics, girl, just chilling out here in the shade on this beautiful summer day, aren't you? Derek, yes, that's right. Diana, okay, but you're not needed for this video yet, so relax. A couple of months ago, some guys contacted me and told me they had access to a UV camera. Do you know what that is? Yes, it's basically a camera that allows you to see the world in ultraviolet, which meant a few things to me, it meant I could see what this looks like in UV, I could see what your face looks like without any lotion or makeup in UV and I could see how

sunscreen

appears on your face in ultraviolet, so I said yes, please come visit me in San Diego and bring your UV camera, and the guys from the very well done YouTube channel on how to do everything showed up at my house , this is what we did.

Yes, on your pants, your pants have tiger stripes. Now you have some weird tan lines after this. I was thinking that's crazy, oh, those are devil horns, yeah, bigger, better, yeah, yo, come on, let's do this, it's that show up thing, oh yeah, oh. Yeah, crazy, yeah, it was a fun day, but I have to explain why I'm here with Derek from Veritasium, who is also making a video about the world in UV. I've been making this video for about a year and I'm here to do it. he finished it, but for this video we are going to cut it several times to discuss the

sunscreen

controversies.

There are a lot of misconceptions about sunscreen and we're going to clear them up, yes, but for now I'm going to turn it around. to Diana in the studio back to you Diana the first thing I wanted to investigate was if different SPF, that is, a sun protection factor that is actually supposed to indicate how strong the sunscreen is, but I still wanted to see if Different SPFs of sunscreen look different. under ultraviolet light and then I wanted to compare whether a high SPF, such as SPF 100, is more effective than the normal high SPF, such as SPF 50.

Here was my thinking with a camera Ultraviolet: Things that look lighter emit or reflect ultraviolet light like the wall behind us. and things that look darker, like the shirt I'm wearing, absorb UV light, which is something I think you want to know when it comes to sunscreen because UV light, of course, is part of the light spectrum or electromagnetic. Waves from the Sun and UV rays are just on the opposite side of the violet part of the visible light rainbow, meaning it is a wave that has a shorter wavelength, meaning it has a higher frequency than any visible light and, in the end, it can do more. damage to molecules like DNA or cells and as we all know it's been linked to skin cancer so I thought if you look at your skin with sunscreen on you should see the UV light being absorbed so it should look darker and yes, like when we put sunscreen on it, it looked like face paint, we even managed to do graffiti outside the truck with sunscreen, but of course you can only see it with the UV camera, so my hypothesis was that the sunscreen with the highest SPF should look darker with the UV camera, so we tested a bunch of different sunscreens with different SPF on a grid on my arm drawn with permanent marker, this is what paint looks like, yeah, It looks like metallic black paint.

Initially we saw that yes, low SPF areas do show. Less dark, it can be said that they do not seem to absorb as much ultraviolet light, but curiously there is not much difference between 30 and 110 spfs and I have heard a rumor that with spfs above 50, something really high is no good. something more than SPF 50. So I looked in the scientific literature about this and actually found a study that came out this year in May 2018. that tested 199 people with SPF 50 and SPF 100 sunscreens over the course of about six hours of sun exposure the subjects burned more with SPF 50, but they put a little disclaimer at the end of the article that leads you to conclude that more research needs to be done on whether there are more long-term benefits from using SPF. 100 versus 50.

Hey guys, I just want to pause on this for a second because I still think it's weird that I've had this conception that above SPF 50 you don't get any more benefits and Derek, let me know what you think about this , but I think I found out where that conception came from and I think it's from a rule proposed in 2011 by the FDA, the Federal Drug Administration, yes, they proposed a rule that would limit the maximum allowable SPF labeling to more than 50 thoughts. I do not know too. I think the idea that the vast number of sunscreens are basically equivalent is strange.

You know, when I lived in Australia, people were limited to putting only 30 or so in bottles of sunscreen and now they've moved it to 50+, but I think that's still the case. It's a good idea because as those numbers increase, you get diminishing returns, so what's the difference between 50 and 100? Well, actually it's not that much, because much of its effectiveness comes down to how much you apply it and how well you apply it. Just so you know, I think it's just a marketing gimmick to say this is a 75 or this is an 80 or this is a tiny 9, so obviously SPF and the effectiveness of different sun protection factors is still an area active research anyway.

For the fun day at hand when we were looking at sunscreens with different SPFs, we tried a different sunscreen with SPF 25 and something strange happened. It was actually lighter, very light, this means it doesn't absorb UV light, but could it still be sun? yelling yes, if it reflects UV light, which is most likely. What's going on here with this sunscreen that contains zinc oxide, which is a substance known to reflect some types of ultraviolet light? So this is where I got very confused. I started looking for some sunscreen. ingredients and what they do and why some are reflective and others are absorbent and I ended up falling down the rabbit hole of sunscreen controversies.

I'll get to the discussion of the health effects of different sunscreen ingredients in a minute, but I found out that Hawaii recently banned some sunscreens in the state, the reason being that the ingredients were found to be oxybenzone and octanoxate which contribute to coral reef bleaching, a process by which coral polyps expel the small algae that live inside them, actually sounds like an exorcism, but it is actually a bad thing, so from 2021 Hawaii will ban any sunscreen with those ingredients. This ban was based on recent research that raises the question of whether the health effects and environmental effects of sunscreen ingredients are not well understood.

Well, I'll pause here again. because I feel like this is a good discussion for us, there's a lot to go over here, but I want to start with that SPF 25 sunscreen that really came through, yeah, I mean, there's two main ways that sunscreens can protect your skin from ultraviolet light, one of The way is by absorbing that light and converting that energy into heat. Another way is by reflecting light and what you saw was clearly more of a reflection. Now in the media they are often called physical versus chemical sunscreens, which may not be the best designation I have.

I don't think it's the best because you know they're all chemical maybe it's a better distinction to say that chemical sunscreens are organic because they are organic molecules that have these carbon chains and the so-called physical sunscreens are inorganic molecules like titanium. zinc dioxide and oxide, so they reflect a little more but they also scatter light, absorb light. This chemical versus physical distinction bothers me, as you know, because I think it's used misleadingly on a lot of health blogs and in a lot of media saying that you should avoid these chemical sunscreens because they're chemicals you don't like.

I don't like it because they're all chemicals, right, they're all chemicals, right? I think there is a deeper reason. why would people say chemical versus physical because chemical might describe by virtue of its chemistry that's how it interacts with light, whereas you know a physical sunscreen by virtue of its structure is actually how it interacts with light, you're right when you say For marketing people try to use the chemical label as some kind of negative term and I think it's actually hiding an important discussion about the potential safety issues of what they call chemical sunscreens, so we're finding out things about the ingredients. of sunscreens all the time.

For example, recent research has shown that some sunscreen ingredients and, in particular, some organic sunscreen ingredients can reach the bloodstream and breast milk through the skin, leading the FDA to recently state This is an important discovery that should be considered as We continue to evaluate the health and safety of sunscreen ingredients. In fact, the FDA recently rejected eight proposed new sunscreen ingredients because it felt there wasn't enough science to prove these ingredients were safe, but my question is, now that we know the ingredients in sunscreens. can enter the body through the skin if we were to reanalyze those 16 ingredients, if we were to look at them through the lens of new research and judge them with the same thoroughness with which we judge these eight new ingredients, for example, so The surprising thing to me is that there is still a lot to learn about sunscreen.

I think it's a little strange because on one hand you say these health blogs say chemicals are bad, but on the other you say maybe chemicals are bad. Because they haven't been tested yet, that's not why people say they are bad, and in fact, some of them may be perfectly fine and are lumped in with the ones that do cause skin allergies, like saying because they are chemicals, is the reason you could potentially lose a ton of great sunscreen ingredients that are going to be really effective in protecting the population from skin cancer, but people have lumped them into this chemical category which really just means molecule organic. category maybe we'll find ones that don't absorb into the bloodstream as easily, you know what I mean, yeah, there's a lot to learn, but at the end of the day I think you have to put on sunscreen at the end of the day.

The day you want skin cancer because it's the most common cancer in the US? You heard it from the man that we're sunscreen kids. Oh yeah, also thanks for watching this video and watching Derek's video which will be about world in UV something about sunscreen but mostly also really cool experiments that we filmed yesterday check out the how to do everything guys video at the end they made sunscreen yeah awesome yeah look I'll link to both videos in the description and at the end of this video or whatever thank you so much for watching and happy physics thanks to Curiousstream for supporting PBS Digital Studios Curious Stream is a service subscription streaming service offering documentaries and non-fiction titles from a variety of filmmakers, including Curious.

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