Melissa: 00:09

Hey. I'm Melissa.

Jam: 00:11

I'm Jam.

Melissa: 00:12

And I'm a chemist.

Jam: 00:13

And I'm not.

Melissa: 00:14

And welcome to chemistry for your life.

Jam: 00:16

The podcast helps you understand the chemistry of your everyday life.

Melissa: 00:20

Okay, Jim. Today's topic Yes? Is sort of a second part of a

Jam: 00:25

topic. Oh, really? Which one?

Melissa: 00:28

We're piggybacking on the deodorant episode.

Jam: 00:31

Oh, nice.

Melissa: 00:32

Yeah. We're gonna be talking about sweat.

Jam: 00:36

Sweet. I mean, sweat. Sorry.

Melissa: 00:40

Dang it. I didn't even see that one coming. Okay. Part 1 for sweat is 1, how does it cool you? Part 2 for sweat is what are scientists doing with our sweat right now?

Jam: 00:57

Should they be?

Melissa: 00:59

Doing stuff with your sweat? Yeah. Well, they are. So

Jam: 01:03

Yikes.

Melissa: 01:04

Whether you want them to be or not, they are.

Jam: 01:07

Yikes. This is gonna be a huge scoop. This is gonna the press is gonna have a field day on this one.

Melissa: 01:15

I think the press has already posted some information about this.

Jam: 01:20

Oh, okay.

Melissa: 01:22

So for the first part, do you know how sweat cools you?

Jam: 01:27

Do I know?

Melissa: 01:28

Yeah. Do you know? Oh. What's your baseline here?

Jam: 01:34

I would think because it's wet, it might help cool you, especially if there's a breeze.

Melissa: 01:40

Okay.

Jam: 01:40

That's all I can think of. I mean, my experience, it's only ever been, like, somewhat helpful. It was kinda a breeze. So you sweat and then The wind kinda hits you and

Melissa: 01:54

Oh my gosh. There's so much more to it.

Jam: 01:56

Yeah. That's all I know. That's it. That's it. But most times I've most times I don't really feel very cold by sweat, to be honest with you.

Melissa: 02:02

Well, you may be more cold than you know. But, also, we're in a humid environment, and that can impact it.

Jam: 02:08

Right. Right.

Melissa: 02:09

So we have talked about endothermic changes and reactions and exothermic changes and reactions.

Jam: 02:16

Mhmm.

Melissa: 02:18

Exothermic, heat exits. The heat leaves the system. So you mix 2 things together and they start to feel hot of their own accord, that's exiting that system. It's giving off heat.

Jam: 02:30

Right. Right. Right.

Melissa: 02:31

Exit exothermic. Yeah. Endothermic, you're putting the heat in. So that means to get from one thing to another, you have to heat it up.

Jam: 02:42

K.

Melissa: 02:42

So if you put a bunch of chemicals together and then you put them on a boiling Or on a hot plate. Yeah. That is endothermic. You're putting heat into it. Right.

Jam: 02:53

Right. Right.

Melissa: 02:54

So can you remember an example of an endothermic and an exothermic change?

Jam: 03:02

Endo, boiling water.

Melissa: 03:04

That's right. You put heat into it.

Jam: 03:06

XO, the hand warmers. Right?

Melissa: 03:10

Because they're giving off heat.

Jam: 03:11

Right?

Melissa: 03:12

That's right. Good job. Okay.

Jam: 03:16

When when you started using those words, I was thinking you might ask me, and so I was like, wait. Quick. What are the examples? What have we talked about?

Melissa: 03:24

You guys got big. Like, oh, no. So sweat is excreted by your skin. Don't really know the process behind that. But what happens next is something called evaporative cooling.

Melissa: 03:42

The sweat evaporates, so it goes from water to a gas. Essentially, the same process as boiling water.

Jam: 03:54

Okay.

Melissa: 03:55

It's an endothermic physical change. K. The heat from your skin, from your body is putting put into those water molecules until they turn into gas and evaporate.

Jam: 04:09

Weird. So it's gas? Why is there so much liquid then?

Melissa: 04:13

So the cooling effect is when the liquid turns to the gas. When the liquid evaporates because the heat from your body has been putting enough into where it can evaporate. However, if it is already humid, it's harder for those water molecules to turn into water vapor or the gaseous state because there's so much of that already in the air.

Jam: 04:35

Right.

Melissa: 04:35

So it just kind of stays on you.

Jam: 04:38

Right. Interesting. Weird. So it's like just sweat that Couldn't fully escape. I couldn't turn to gas and fly away.

Melissa: 04:48

That's right.

Jam: 04:48

Just kinda hung around in our bodies.

Melissa: 04:50

Mhmm. I think it does still have some effect because the specific heat of water is high, so it can take in eat from your body, but the evaporating effect requires the energy to turn it into a gaseous molecule. It goes away and then more I can come and take its place. Mhmm. So there you go.

Jam: 05:13

Weird. That's not what I thought.

Melissa: 05:15

That's not what you thought. How interesting.

Jam: 05:18

I mean, I just thought, like, like

Melissa: 05:20

I mean, the same thing. It cools you down

Jam: 05:21

a lot if you just, like, put some water on your head. You know? Like, Just having some moisture somewhere can kind of even if it's, like, room temperature water.

Melissa: 05:30

But that is because the water is absorbing the heat. So it's just like how right now. My computer has been overheating, So I put something beneath it that could absorb the heat, a cold pack

Jam: 05:46

Mhmm.

Melissa: 05:47

That has ample space to absorb heat.

Jam: 05:50

If only we had, like, built in cold packs.

Melissa: 05:53

Our sweat is a built in cold pack.

Jam: 05:55

Oh, sorry. I should say, wow. It's like a built in cold pack. I'm just kidding.

Melissa: 06:01

So the reason this came up is we were we rode our bikes to the town square

Jam: 06:06

Mhmm.

Melissa: 06:07

And my roommate and I, and her seat was in the sun just baking.

Jam: 06:12

Oh.

Melissa: 06:13

And then to cool it down, we poured some water on it, And the water evaporated so quickly. And I said, oh, how does your seat feel? Is that evaporative cooling work? That's how sweat goes too. And she said, what?

Melissa: 06:28

Because her seat dried up really fast, and then it was much cooler to the touch because that water absorbed the heat. The heat was put into the water molecules so that they had the energy to become gas molecules. That's evaporative cooling. That's how your salt works, and that's why it works to dump water on something.

Jam: 06:46

Weird. That's weird, dude.

Melissa: 06:48

Mhmm. You're just giving an outlet for the heat To go into.

Jam: 06:54

Yeah. So if you sweat when it's not very hot outside, does it also have a hard time Evaporating? Does that have an effect?

Melissa: 07:04

I don't actually know the answer, but I would assume the answer is has to do with If the external temperature is warmer than your body temperature, you're taking in all that heat into your body because it Sort of like what we talked about, how heat tries to evenly disperse, so everything's the same temperature. And if it's colder than your body outside, then your body is already putting a lot of heat out into the colder air. That would be my instinct in response to that.

Jam: 07:40

I've heard that if you Can help it not to sweat when it's really cold, like if you're in very cold environments, because again, cause hypothermia because it cools you off well.

Melissa: 07:54

Yeah. I'm sure that would that's another thing for your body to be giving heat off into. So it's giving heat already into the cold air and also to your sweat. And water can take in a lot of heat Before it starts to warm up, remember, because it has that high heat capacity. That's why the sun can beat down on it all day, and your concrete Super hot or the sand is super hot, but the pool water is not.

Melissa: 08:20

Yeah. Yeah. Or the beach is not the ocean.

Jam: 08:24

Thanks, wedding. It's pretty weird.

Melissa: 08:26

Yeah. I was worried this wouldn't be interesting enough on its own, which is why I added in our fun facts at the end.

Jam: 08:33

Oh, sweet. Well, I still love fun facts. Scientists. I always love fun facts.

Melissa: 08:37

Okay. Well, tell me this back, and then I'll tell you what the scientists are up to.

Jam: 08:41

Sweet. Okay. So You're hot. You're running around, biking around, walking around, working hard, whatever you're doing.

Melissa: 08:49

I'm doing Erica Davis Fitness LLC.

Jam: 08:51

Yep. Yep. And you start to sweat. Your body is taking the heat In your body.

Melissa: 09:04

Mhmm.

Jam: 09:05

Putting it into the water that's in your body, which we have a lot of. Right?

Melissa: 09:10

Mhmm.

Jam: 09:10

Into some water in your body. And because it can take a lot of it, it's doing that and pushing it out. I guess part of this is the the part that you didn't Fully understand, but, like

Melissa: 09:21

The sweat takes in the heat when it's already on your skin. So the sweating happens, and then there's water on your skin, and then it takes in the heat.

Jam: 09:30

Oh, got it. Okay. Okay. So it just pushes the yeah. You're hot, and so it puts water or not really water, but sweat, you know

Melissa: 09:37

Right.

Jam: 09:38

Out because you're hot.

Melissa: 09:40

Right.

Jam: 09:40

And then that starts taking in the heat from your body.

Melissa: 09:45

Right.

Jam: 09:46

And then it starts evaporating if it can. Right. And having evaporative cooling as it takes that heat away and takes it off up into the sky Yep. You become a little bit cooler.

Melissa: 09:58

Yes. That's exactly right. It takes the energy putting your body is putting in to the water molecules causes those water molecules to move around more and more and more and more as they take in more and more energy

Jam: 10:13

Mhmm.

Melissa: 10:13

Transferred in the form of heat. And eventually, they will be so wiggly and moving around that they're gonna break free of each other and go into that gaseous phase where they're not in the liquid phase anymore.

Jam: 10:24

And they can take in a lot of heat, so they're feasibly taking a good amount of heat away from you when they do that. Right? Mhmm. Because of a high heat capacity.

Melissa: 10:34

Right.

Jam: 10:35

Interesting. Yeah. I like that.

Melissa: 10:38

That's it. That's how sweat works.

Jam: 10:39

So your body's trying to help you by sweating.

Melissa: 10:42

We already 100%.

Jam: 10:44

Are near that part. But there is a lot of downsides that come with sweating. Like, we talked about the deodorant episode, obviously. It it can be because of bacteria and stuff like that cause not great smells, and then there's could just be, like, discomfort with sweating, Especially in a hot Texas summer. And so there's obviously a lot of downsides, but it is helpful to be reminded that my body is just trying to help me.

Melissa: 11:09

Your body's trying to help you. Your body is helping you stay at a safe temperature, a safe and comfortable temperature

Jam: 11:16

Mhmm.

Melissa: 11:16

To keep you alive and well.

Jam: 11:19

And that's the point.

Melissa: 11:21

That's the point. And there are some negative side effects perhaps, such as You're gonna maybe smell bad because of the bacteria.

Jam: 11:31

Mhmm.

Melissa: 11:31

But, I mean, what's that for the cost of being alive?

Jam: 11:35

Exactly. Would you rather be smelly or dead?

Melissa: 11:39

Exactly. I'd rather be smelly.

Jam: 11:41

Yep.

Melissa: 11:41

Or I'd rather be Like the listener who wrote in whose girlfriend didn't smell bad when she sweat. Yeah. So I'd rather be not smelly and not dead.

Jam: 11:51

Yeah. That'd be the best. We can that that could be one of the options. That'd be I'll I'll take it.

Melissa: 11:56

Okay. Well, here's the crazy thing that scientists are doing right now. Okay. Okay. So we talked about in that bonus episode and in the antiperspirant deodorant episode

Jam: 12:07

Mhmm.

Melissa: 12:08

Has sweat has all kinds of stuff in it. It's not just water. It has salt. It has all kinds of stuff including you can excrete Different smells based on your emotions and your medical health and all of that. Yeah.

Melissa: 12:24

So I remember this person came to a lab group meeting that we had and discussed something they were developing, and that is wearable technology, Like a Fitbit or an Apple Watch that can test your sweat.

Jam: 12:40

Woah.

Melissa: 12:42

And so I went and looked this up, and I found a paper that had a smartwatch. And this was a crazy cool one because it was self powered, But it was constantly measuring your glucose via your sweat.

Jam: 12:56

So

Melissa: 12:56

that's the sugar levels that are important to be tested constantly for people with diabetes. Yeah. So your sweat and the way scientists study it Could revolutionize health care for diabetics.

Jam: 13:12

Wow. Wow. Goodness gracious.

Melissa: 13:15

That'd be crazy.

Jam: 13:16

I mean, could have to pretty much prick their finger to test their blood sugar. Let's fight that right now. Right?

Melissa: 13:21

Mhmm. Okay. So that's one crazy cool way Mhmm. That they're harnessing the power of sweat for the betterment of humanity. Another cool way, A paper I found had Band Aids that you could just put them on your skin, And they're superhydrophobic, so they're repelling water except for these specific circles Superwettable.

Melissa: 13:57

So very trying to get wet Mhmm. Patches. So the sweat from your skin goes from your arm over to the Band Aid or whatever.

Jam: 14:09

Mhmm.

Melissa: 14:09

And on that superhydrophobic part, it just The water just slicks right off until it gets to these parts that really wanna get wet. Mhmm. And those little Pieces have chemicals in them to test the pH of your blood, so that's the acidity, to test your glucose, to test all these things to make sure they're in the normal range, and then you can pull out a smartphone and look at the color on the Band Aid that changes to indicate that. Dump. And boom.

Melissa: 14:38

You can check and make sure your levels are good just like that.

Jam: 14:41

Wow. Dang, dude.

Melissa: 14:43

It's I mean, I say a Band Aid, but it's Not actually to bandage a cut. It would just be an adhesive like a bandage that you just stick on your arm, and it tests all the sweat, and it gives you that information.

Jam: 14:55

Interesting. Yeah. So I guess yeah. Like like a like a like a Band Aid or like a nicotine patch or something like that that just Right. Is meant to just hang out on your skin.

Jam: 15:05

Mhmm.

Melissa: 15:05

Wow. With little wells almost, like, little collection sites that really want to grab that Sweat up, and then they have each it was 4 different areas that each tested a different thing, and you can look at it with your phone.

Jam: 15:19

Wow. Dang. That's awesome.

Melissa: 15:22

Isn't it amazing?

Jam: 15:24

It I didn't even think about the fact that sweat could have really valuable data in it. Like, Like, we've got whatever makeup we have to us, pH or, you know, glucose level or whatever it is

Melissa: 15:47

Right.

Jam: 15:47

Might Be really good, viable information to know depending on what conditions you have or what things you need to be monitoring or for maybe all of us at some point.

Melissa: 15:58

Right? It's I mean, it's a lot like having I have a Fitbit that I wear, and I know my heart rate, and I know all these things, and that's revolutionary technology

Jam: 16:06

Mhmm.

Melissa: 16:07

For our health, and maybe we can learn other things that are gonna help us be more informed about our health. Yeah. Yeah. Isn't that so cool?

Jam: 16:16

Seriously, I have an Apple Watch, and so I've also kinda gotten really into, like, just the metrics that it does have Mhmm. The things you can kinda get Information on and get interested in about, like, your heart rate or, like, what your resting heart rate is and what it is when you're active. And just kinda keeping up with that information is really interesting.

Melissa: 16:35

Right.

Jam: 16:36

And it seems like there's a lot of good value there for that kind of technology developing more.

Melissa: 16:42

Yeah. Isn't that so exciting?

Jam: 16:44

Yeah. You go, scientists. You can have all sweat and mind you need. Okay? I'm sorry about earlier.

Jam: 16:50

I assumed a little bit, I don't know. Questioning y'all's intentions about wanting my sweat, but now I'm a believer and you guys can have all the sweat of mind that you want.

Melissa: 17:00

I'm so glad that you're a believer and that the scientists are using our sweat for valuable options.

Jam: 17:08

Me too.

Melissa: 17:10

Well, that's all I have for you. I just wanted to give you the basics on how Sweat keeps us cool and to give you fun facts about What they're doing with sweat over in the science labs right now.

Jam: 17:20

Dude, awesome. I loved it. That's cool. It's perfect timing too. I'll probably be sweating a lot very soon with It being hot in Texas.

Jam: 17:27

So That's

Melissa: 17:28

what I was thinking, but then I saw the Instagram story from one of our followers, Shayel

Jam: 17:32

Mhmm.

Melissa: 17:33

Who's written in a couple times, and I think it's winter where she is in Australia.

Jam: 17:45

Chunk of the globe, we're experiencing the heat, so we're definitely jealous of you guys in the southern hemisphere.

Melissa: 17:53

Yeah. And also just because you live in somewhere beautiful like Australia, and we live in somewhere that's just okay. Yeah. I

Jam: 18:01

don't wanna say anything bad or too detailed, but I'll tell you it's no Australia. You know what I'm saying?

Melissa: 18:07

Yeah. I could I can agree with that.

Jam: 18:09

Is it time to talk about our weeks?

Melissa: 18:11

Oh, yes. Definitely.

Jam: 18:13

I've got some kinda nerdy, but fun things that I did this week that I wanna share with you.

Melissa: 18:18

That's very exciting. And I don't already know this, and you teased me with it saying you had some fun stuff early on.

Jam: 18:25

Mhmm.

Melissa: 18:25

So I'm excited.

Jam: 18:27

That's right. And I'm thinking about just slightly mentioning it a little bit and then changing topics so that you still don't know what I was gonna share about.

Melissa: 18:35

No. Tell me. I'm very

Jam: 18:38

Excited. Okay. So, this is kinda in the vein of what I shared about a few weeks ago with projects I've been doing to get ready for a baby being in this nursery, but also just house house projects and how satisfying those can be. So I've kinda continued down the Rabbit hole of messing with electricity some, in safe ways, by the way. But, so we had to replace We painted this hallway, which meant we had to replace all the outlets and light switches, to make them match color wise.

Melissa: 19:12

And Right. Right.

Jam: 19:13

That included some light switches that are I forget exactly the right wording, but I think they're 2 pole, meaning 2 different light switches control the same light, which means you get to wire them a little bit differently, and you actually have to buy slight different light switches for it. So I had to go down this rabbit hole of figuring out what that even was, wrap my head around how to do this myself, and I Failed the 1st time. I had to go buy the right switches, which is how I learned that they were different at all. But, after that hiccup, I figured it out.

Melissa: 19:48

And Oh, that feels good.

Jam: 19:50

It really does. With the help of YouTube, I have to give YouTube some cred, I figured out how to how to replace light switches. And they're also the, like, rectangular ones, which are like a big kind of rocker instead of a little toggle, Which I like how those look. And

Melissa: 20:06

Me too. Yeah. I like how those look.

Jam: 20:08

And there are 2 switches we had on one end of the hallway that were not intuitive. Like, the wrong one did the wrong thing, you ever experienced that, you like the one on the right, you kinda expect to do the light on the right, and it doesn't.

Melissa: 20:19

Right.

Jam: 20:19

And so I switched those to be correct now. So that was the first thing. The second thing is a little crazier is I replaced a light fixture. I switched it from a fluorescent light fixture that has, like, a, Like like a voltage converter thing and a lot of complicated stuff to it to an LED light fixture in our bathroom.

Melissa: 20:40

Nice.

Jam: 20:42

So I did that. That was dicey. Did that all by myself, and it was a little bit crazy because then the breakers are often there's not much light, so you kinda have to use a flashlight or whatever. But I did that, and I got it right on the 1st try, which that was

Melissa: 20:55

Oh, wow.

Jam: 20:56

Kinda nuts. And some people are probably listening thinking this is all really easy, and it is. But for me, I'd never done it, so it did not feel easy. Did not seem easy from the outside. And then I also had this There was a shelf that was falling out of the wall from the previous owners

Melissa: 21:10

in our bathroom. Mhmm.

Jam: 21:12

And so I I sanded and stained a piece of wood and Put it on the wall and mounted that really solidly to the stud and then put the shelf back on. And so I did all that in 1 weekend, and it just felt So good to get those things knocked out. I kinda needed to do them all together and get them done. But

Melissa: 21:30

Right.

Jam: 21:30

Just that feeling of getting A lot of projects done and them go pretty well and none of them failed really hard was great. So that was my week.

Melissa: 21:40

Wow. Congratulations.

Jam: 21:42

Good. Thank you.

Melissa: 21:44

I'm not sure how I'm gonna follow that up. I haven't done anything that interesting, exciting, or satisfying this week.

Jam: 21:50

You might have done things that were less nerdy, and potentially more exciting to most people.

Melissa: 21:58

Well, this isn't less nerdy, but one of the things that I've been trying to do just in this kind of new phase in my life, I've Been trying to read more books, so I just do 15 minutes of reading a book at night.

Jam: 22:12

Nice.

Melissa: 22:13

And I love reading, and I Have at different times. A lot when I was really young and then a lot when I first graduated from college. Read a lot or listened to a lot of audiobooks, and I kind of just got into another one of those phases right now. Yeah. And I have been knocking out books left, right, and center.

Melissa: 22:35

A book called Ghost Boys. Can't recommend it enough. Finished up David Sedaris, Me Talk Pretty one Day.

Jam: 22:42

Nice.

Melissa: 22:42

And I had been reading that book out loud to my mom in the hospital, so that was kind of a fun Trip down memory lane to to read and

Jam: 22:51

Yeah.

Melissa: 22:52

Finish that and think about how she would have enjoyed it.

Jam: 22:54

Yeah. And it's a funny book, so probably

Melissa: 22:57

Oh, yeah.

Jam: 22:57

List of spirits sounded like that too.

Melissa: 23:00

Oh, absolutely. And I am almost done with the book called l m n o p about Well, it's about letters, if you couldn't have guessed from alphabets alphabets.

Jam: 23:11

Letter. Right? Because l l m n a v is all one letter.

Melissa: 23:19

Oh, man. Well, it's actually Ella, e l l a, Minnow, p p e a. Oh. It's a girl's name, l m n o p.

Jam: 23:29

Dang. That's I like that. That's Sounds like a a really good character to have in a kid's book, honestly.

Melissa: 23:34

So I've just been getting into books again and then Just knocking them out and making room for all the books on my bookshelf that have been sitting abandoned because I just need to constantly buy new books and then never read them or borrow them or whatever.

Jam: 23:51

Dude, that's great. That feels great to get books knocked out and get back in a groove of making that habit again. That's awesome.

Melissa: 23:57

Yeah. I'm really excited. Thanks. Thanks for being impressed by my books, and thanks for sharing your Very impressive technology of electricity tasks, and thanks for coming to listen and learn about sweat.

Jam: 24:12

Anytime, dude. Thanks for teaching us. Appreciate it.

Melissa: 24:15

Was my pleasure.

Jam: 24:16

Mohsen and I have a lot of ideas for topics of chemistry in everyday life, but wanna hear from you. If you have questions or ideas, you can reach out to us on Gmail, Twitter, Instagram, Facebook at chem for your life. That's like to help us keep our show going and contribute to cover the cost of making it, go to kodashfi.com/chem for your life, and donate the cost of

Melissa: 24:39

a cup of coffee. If you aren't

Jam: 24:40

able to donate, you could still help us by subscribing on

Melissa: 24:42

your favorite podcast app and rating and writing a review on Apple Podcasts. That helps us to be

Jam: 24:47

able to share chemistry with even more people.

Melissa: 24:49

This episode of Chemistry For Your Life was created by Melissa Collini and J. M. Robinson. References for this episode can be found in our show notes or on our website. Robinson is our producer, and we'd like to give a special thanks to a Hefner and a who reviewed this episode.