COMO essa BOLSA ESQUENTA SEM ENERGIA ELÉTRICA?

Today we are going to test an instant hot bag that works forever that just arrived here at Manual do Mundo. It's pretty crazy here. There's some liquid inside the bag, it's at room temperature, it looks like any other Water, and if I press a little button, a little metal that's inside, it will heat up suddenly. And the craziest thing is that there's no battery here, there's nothing, and I still manage to do this over and over again. No, it is not infinite energy. Now if it really works, we'll see today. First of all, what is this thermal bag? It's a bag that usually contains water, something Else inside, that we heat on the stove, in the microwave, put on top of some parts Of the body that are hurting. It can even be placed on the belly to relieve some Colic. In colder countries, people also use these bags to warm the body. So, imagine you're leaving to go to school, it's minus 10 degrees, snow is hitting Your face, you take a little warm bag and put it in your pocket to warm your hands And leave the house a litte warmer. The problem is that this hot bag that holds Water is kind of boring to prepare, right? You have to put water inside the little Bag there, use a stove, heat it up… it's not all the time that you'll have a stove Nearby to keep heating the thermal bag. So, the guys invented these little hot bags That heat up by themselves, like it was magic. But here at Manual do Mundo, we always Know that it's not magic, and that's what we like to find out. So, in addition to Testing this little bag that I showed you at the beginning of the video, we wanted To test two more today. The one that is sold in Japan warms the body and the other That is sold in Brazil relieves colic. Let's test Japanese first, just because you Can't understand anything that's written. I can't even do this joke anymore, because, In reality, with Google Translate I can aim at the packaging and see what is written. It is saying that it lasts 8 hours, that the minimum temperature is 40 degrees, The maximum is 70 and the average is 58. It's hot as hell. Disposable body warmer. So, we already know that it can be used only once. It's saying that all you have To do is open it and shake it and it's already working. It's not to be used directly On the skin, because it gets too hot and you can't use two at the same time as that will be even hotter. But I want to see if this one will heat up. An empty bag. I mean, there's something inside, but I don't know what it is. 28 degrees, but then it was my body that warmed up this thing. 30 degrees, it got a little better. About two minutes later it started, it's already warm. If I had been cold, this would already help in some way. 35 degrees, it's not rising much beyond that.

I'll put it in my pocket, and we'll see later whether it heats up a little or not. Relax, in a little while we're going to cut that bag, yes. In the meantime, I'm Going to open this other one that is manufactured in Brazil, but it already says Japanese technology. Maybe it works in a similar way to another. It also says it Works for 8 hours and heats up in contact with air. Very similar to the other one, except that this one has an adhesive on the back that We can stick to our underwear, because we have to put it here near the belly, below. I'm not going to stick it on my underwear, it's going to be kind of weird. Look, in meanwhile, I can tell you that the little Japanese package that's in my pocket Got really hot. I don't know if it actually warmed up or if the feeling is different There. Look, 37. It's very comfortable to have this thing in your pocket. Let's open it up to see what's in it. Let's see here on the packaging. Iron powder, water, wood powder, activated carbon, vermiculite and salt. In Brazilian one, iron powder, water, activated carbon, water-absorbing polymer, sodium Tripolyphosphate, sodium sulfite, wood powder, vermiculite and sodium chloride. Practically The same thing. In fact, this one is already warm like the other one. Let's open The other one too. The Brazilian one is a little more humid, but they are very similar. It's pretty weird for us to think that iron powder will heat up for some reason, but it makes perfect sense. When it's inside here, the iron powder has no contact with the air. When we open it, the oxygen in the air starts to react with the iron powder and oxidizes the iron, rusting the iron. And this is an exothermic chemical reaction, that is, it is a chemical reaction that releases heat. So, basically, what we feel here is the little heat from rust forming. There is a bag that we tested a long time ago and I think maybe its color is a little Different. It's the same product, but you can see that this one is browner, probably Because all the iron here has already oxidized. In our day-to-day life, if you take An iron bar that is rusting, if you put your hand on it, you will not notice any Difference in temperature because this oxidation of iron is very slow. But here they did some things to speed it up, like putting the iron in a very fine Powder and mixing some other ingredients that will speed up the reaction, like salt, for example. And now you can put your hand and feel very warm. 50 degrees! Let's join with another one here that I want to see this thing heat up a lot. I'm Increasing the contact with oxygen, so theoretically it will warm up faster. I'm Making a small oven with my hand here and it's getting to 59 degrees, it's really Hot. That's why you can't put it directly on the skin. But these here are the disposable hot bags.

This reaction of oxygen with iron is not easy to reverse to use the bag again. The star of our video is the little bag that you can use endlessly. And it works in a completely different way. I'm not going to open anything, just give a tick, give that flat iron that's inside a little stir. Oh, it started, it started, it started, it started before time. I moved, no! Look how nice it is. It's hardening. Wow, what a beautiful thing. And it's already really hot, 54 degrees right off the Bat. Look, I'm going to tell you that this is more or less at the limit of what We can bear on our skin, ok? If I put this inside my clothes, right on my skin, It would burn me, it has to be in my pocket. This one is prettier, more instantaneous, On the other hand, all the heat it had to generate, it generated all at once. So, The temperature is already dropping, it's already 51 degrees, while the others there Last more or less 8 hours. An hour passed and it cooled down completely. It's already at room temperature, but it's become rock hard. Oh, I can even move it a little bit, but it gives the impression of, I don't know, a solid object. I can't just press the little metal here anymore and this thing gets hot again. I need to give it energy back. I have to wrap the bag in a cloth, put it in water Until it boils, then it will start to become liquid and there cannot be any solid Crystals inside. It's kind of obvious that at this point it still doesn't make much Sense for me to squeeze the metal again to make it hot, because it's already hot. In fact, it's above the temperature it was before, because I heated it on the stove. Can't hold it in your hand. For this to work again, we have to let it cool down. But there's a nice thing about it. If you lived in a cold country, you could heat It up here during breakfast, carry it in your pocket warm with the heat that came From the stove itself and, when it's time to go home, you press the little metal. In this case, what we are going to do here is wait for it to cool down. It's cooled Down and now I can squeeze the little metal. Remembering that where is the energy Coming from here now, right? That heat, the chemical kept it inside and will return It back to me. I provided this energy the moment I warmed up in the water. It doesn't Have infinite energy. It has to come from somewhere. Look how crazy it is. It's very beautiful, you can see the crystals forming in a Radial way, as if the center were the little piece of aluminum. What is the logic of that? That one was powdered iron. What's inside this one? What's in there is water along With a salt called sodium acetate. If you are an old known Manual do Mundo, you Have already seen this salt around here. So, let's repeat here what happened inside

The bag, but this time outside the bag so we can understand it very well. The sodium acetate is already a little wet, I'll add a little more water, ok? You can see that part of it has dissolved and part of it has not. This happened because sodium acetate has a limit on how much it can dissolve in water. In the case of water, at the temperature here, around 20 degrees, the limit is 46 grams For every 100 ml. This means that if I put more than 46 grams of sodium acetate In 100 ml of water, there will be a part that does not dissolve, that will be a solid part. But now I'm going to heat up this mixture and change something here. In hot water, sodium acetate can dissolve much more. You can dissolve 160 grams of sodium acetate in 100 ml of water. So theoretically this solid part will disappear. Ah, how amazing. It's 100% liquid. There's not a pebble of sodium acetate in here. I'm going to let this thing cool Down, and you've probably guessed what's going to happen, right? Those 160 grams Of sodium acetate that could dissolve in hot water, when it's cold, it's no longer 160, it's 46. So, this difference will get stuck, it will become solid again. No. If we let it cool here very slowly, without disturbing it, without touching anything, It will reach a normal temperature of 20 degrees and nothing will happen. Only part of the sodium acetate will be dying to turn solid again. And the trigger for us to make this happen, to make the sodium acetate solidify, to Make it precipitate, is throwing a little powder of solid sodium there, or we hit it. In the case of this bag, it has that metal plate and some crystals are embedded there. The moment you move the flat iron, we can make the sodium acetate precipitate. And as we learned very well from Ana Maria Braga, we already left a little sodium acetate in this condition. We heated it up, let it cool down and here it is full of it desperately wanting to become solid. I'm going to put a black background that improves visibility. Oh, seriously… It's very beautiful. The only thing I haven't told you yet is that this is very exothermic. It's a process that releases a lot of heat and that's why the glass is hot right now. And that's also why the thermal bag heats up the moment you touch the little metal Inside. Let's see the temperature that got here? Let me give you some good news

That I forgot to mention during the video. We've done this experiment with sodium Acetate several times in Manual do Mundo, it's really cool to do at home, but there Was a problem. People had to buy sodium acetate at the chemistry store. And that's kind of hard to do, but now you can buy this little bag right here. So, you look for a hot bag, hand warmer on the internet and then you can cut the bag Later and use the product inside to do the experiment. If you want to make crystals at home, but don't want to buy it here, maybe it's expensive, Hard to find… you can make a geode of crystals inside the egg using potassium alum, Which is something we know as hume stone.  You can find it in any drug store.