25 Chemistry Experiments in 15 Minutes | Andrew Szydlo | TEDxNewcastle

Foreigners of

chemistry

have disappointed many people. He disappointed the Emperor of China in 59 BC. C. He was told that one of his court officials, Liu Siang, could make gold. A great party was organized at the end of which Liu Siang had to prepare a small amount of the precious metal after working with complicated devices for several hours the only thing he managed to produce was an unpleasant smell Leo Siang was executed on the spot this true story reflects one of the problems that humanity has faced since the dawn of civilization the problem of understanding how substances transform into different substances, this phenomenon of substances transforming into different substances has now become the great science of

chemistry

, so What is chemistry?

Chemistry is the science of substances and how they become different substances and very often we can recognize a chemical change. Because there is a color change when I pour my chemical water from one flask to another, you will notice a color change and this is because I am making a new substance each time. Chemistry plays an important, very important role in our daily lives. lives masses of substances and materials that we use daily or their existence thanks to the science of chemistry Plastics polymers diastas detergents perfumes toothpaste Pharmaceuticals fuels explosives a whole range of notable substances tap water sparkling drinking water masses of substances fertilizers must its existence thanks to the science of chemistry chemistry the science of substances and how they become different substances now here I have shown you some

experiments

with chemical waters and I have illustrated the principle of what chemistry is about the substances that are transform into different substances.

Now I'm going to move on to a different type of water that I have in my container here, this type of water that magicians call disappearing magic water. I'll pour some into my beaker here and now I'll throw it up in the air and show you how. It disappears and I will stand under there and don't look for it, you won't find it and the reason is because it has disappeared into thin air. Why has it disappeared into thin air? Because that is what this liquid is made of. Here I have one of the greatest triumphs of physical science: physics is the science of matter and energy and one of the greatest challenges of physical science in the 19th century was being able to reach temperatures that were low enough to convert the gases in the air into liquids and what I have here is liquid nitrogen and liquid nitrogen has a boiling point of -196 degrees Celsius now, as you see, it is evaporating in my plastic bottle here and the reason Why it's evaporating is because this rum is noticeably hot compared to the temperature of the liquid nitrogen we're in here, about 21 to 22 degrees Celsius.

Liquid nitrogen has a boiling point of -196, which is about as cold as you can get anywhere in the universe, absolute zero, the coldest temperature in the world. The theoretically achievable universe is minus 273 degrees Celsius. Now one of the golden rules when you have liquids that are boiling is to never put them in containers that are tightly closed, that is precisely what I am going to do now. Now I'm going to have these Sprite bottles here and I'm going to put the caps on them really tight and I'm going to gradually put them into these trash cans here now.

The reason you should never do this is because when liquids boil they undergo a huge coefficient of expansion by a factor of about 800. I have poured approximately eight one-hundred-centimeter buckets of liquid nitrogen into each of these bottles and that 100-centimeter bucket. centimeters will expand by approximately 80 liters. Now these bottles have a volume of 0.5 liters and therefore when that liquid nitrogen evaporates it will occupy about 80 liters, generating a pressure of about 160 atmospheres. Now these bottles are very clever, although they are made of shiny polymers, they simply will not withstand that pressure and therefore can explode. They don't always do it.

They explode, but when they explode, the noise is quite substantial and that is why, for example, for 50 reasons, I have put them in the containers now that they will continue to boil. You may hear very loud explosions, so please be warm, but in the meantime, I'd like to show a couple of fairly obvious

experiments

with liquid nitrogen. The most obvious, of course, is to freeze some water. Water freezes at degrees Celsius North and I'm going to pour a small amount of water in here and cover it with liquid nitrogen so it comes out. our water there and now I will pour liquid nitrogen over it and that will obviously turn the water into ice now, unlike the experiments I did with my chemical waters when I mixed chemical waters that were colorless and you saw a color change due to a new Here it is was producing substance, we have a totally different kind of effect.

You see, there is no color change and that is because we have a physical effect here. The real colorless liquids I have mixed are now changing states. one of them is changing from the liquid state to the solid state which is water and the other, liquid nitrogen, is changing from the liquid state to the gaseous state, so here we have the three states of matter in a very simple experiment. As the liquid nitrogen continues to boil, you may hear a slight crackling sound. This is because when water freezes, it expands slightly, and as it expands, the crystals take up a larger area and push a volume, I should say, and push against each other. and sometimes this can lead to huge mechanical forces being set up, which is what the cracking is all about and sometimes the glass can even break, so we'll keep our eyes on this, let the process continue and now I can hear the beginning of a crunch. just cut it off make sure we keep freezing our water and I wanted to tell you that when liquid nitrogen was first produced in the late 1800s, it started a whole new era in the history of technology and that's liquid. gas technology and thanks to that today we have frozen foods we have a large number of all kinds of effects that we benefit from, among them, of course, there are refrigerators now to continue with our experiment also the science of cryogenics to continue with our experiments with low By the way, these temperatures are about five to six

minutes

, you'll hear the bangs, so keep in mind that now I'm going to show you an experiment with a solid.

Here we have a piece of rubber tubing and it is elastic. The reason why it is elastic is. because when you stretch it it returns to its original shape. Now the reason it's springy is because I can hear the pressure building up, so you might hear a pop shortly. The reason it is elastic from a thermodynamic point of view. It is because it is very good here and because it is very hot here because it is very hot here these molecules here have a lot of energy however now I will place the rubber tube in liquid nitrogen and please observe carefully what happens when we lower the temperature and you will notice this effect so interesting what you see of a shower, a shower that comes out of the end of the rubber tube.

Now why is this happening? Well, it's for the same reason that bottles explode there and all. This is because, as liquid nitrogen boils fiercely when it comes into contact with a very hot rubber tube, it expands enormously, as I said, by a factor of about 800, and as it boils, it therefore pushes the liquid nitrogen outward, creating a pressure that is out there, as you saw. there we had uh we had nowhere to escape from and that's why the bottle finally gave way. The knowledge is to inspect our rubber tube that we have here and see what happened to the elastic property that it came into as an elastic solid. but now you see that it is no longer elastic and if I hit it while I am on this table, please watch carefully, then it will break into a thousand fragments.

Now the reason it splits into a thousand fragments is because at high temperatures all the molecules vibrate. a lot of energy, the molecules in the rubber tube have a lot of energy, so they all spin like this, but when you drop them into liquid nitrogen there is very little energy, so the molecules suddenly freeze, freeze, freeze. Of course I'm being silly, but I'm right on an important scientific principle now I just want to show you here, let's see in the meantime. I just wanted to show you how Beaker really cracked, there it is. a piece of glass has fallen and what that shows you is that it simply shows you the enormous intermolecular forces that are set up when water freezes, freezes, the molecules rearrange themselves to form an open network.

Now here I have a beautiful balloon. beautiful balloon and why does it have pressure? It has pressure inside because the nitrogen and oxygen molecules in it move because they have a lot of energy because it is very hot, but if we reduce the energy by pouring liquid nitrogen over the balloon, then you will notice a very, very interesting effect, so watch carefully. I'm going to pour liquid nitrogen over the balloon and when you notice the balloon starting to contract, you'll notice that they're getting smaller. and smaller and takes a very, very shape um it's a shape that doesn't have doesn't have no elasticity has completely collapsed now why is it okay once again it's the same reason because of the low temperatures in the I'm sorry, I think the floor is cracking under me, so everything is frozen everywhere, but we are still fine, please look carefully.

The balloon has now collapsed. It seems like it's very sorry, but we do allow it to warm up a little, shaking it and throwing it into the air. In a very short time let's see if I can catch it I'm sorry it's running away it's running away and as you see it has been restored to its full form now why? Because at warmer temperatures the molecules have more energy and therefore, they move faster and move faster. Now let's continue with my favorite topic, which is fire. This flame here represents this framework that represents one of the greatest traditions of the human race and that, of course, is our ability to make fire.

Know that in East Africa we are the first ancient civilizations, a hundred thousand years ago people could make a fire and maintain a flame. Now I'm going to show you how, thousands, ten thousand years ago, for thousands of years The flames burned like this this is a piece of cotton and you will notice that it is a terribly boring flame adjustments like why is it like this? Because cotton is surrounded by air. Air only contains 20 oxygen. Air was only discovered to be a mixture of gases about 300 years ago and we've been on this planet for a hundred thousand and once chemists discovered that oxygen is the vital component of air that makes things burn better, they started to combine fuels with oxygen or to mix them with oxygen and here I have a piece of cotton that has been chemically combined with oxygen, please notice how differently it burns and we put it here, I don't know, and it is making the flame explode.

I knew it would put out the flame, damn it. That's adding three extra seconds to my talk, it doesn't matter, let me show you quickly, we'll do it quickly. I was ready. I had my matches now. What I wanted to show you. I just showed you the world's first high explosive. There is no cellular Mitra. It was all rubber cotton. I would love to do an exhibition with it, but I can't, we don't have the time that I did to show you a propulsion. This is a mortar, it is a type of device used to propel fireworks into the sky.

I'm not going to set up fireworks. I'm going to push my ping pong balls. Sorry, I have four ping pong balls in my pocket. I have a cage here because I make a cotton cage, here I drop it to the bottom. Sorry, I haven't left. to the bottom I don't know so bad I'm going to I'm going to force it to the bottom I'm sorry I'm fighting a little against the odds and against time let me there we are I think it's I've reached the bottom, if it's not too bad, let's put a fuse there and hopefully when this plays we'll see it.

We'll go up to see how the ping pong balls fly. They manage to get to the bottom of it if they didn't, that's too bad, uh, we will, then they won't, we won't see anything, but there goes our fuse, hopefully, come on, Catch Fire. The time is finishing. Theory Theory, this is very bad. piece of fuse so I'm going to have to put my fingers in your elevator and there we go now to the final things here we have um there we are I don't know if something happened to them yes, they're gone now here we have surely very quickly we have here we have here a balloon full of hydrogen caused a complete sensation among scientists the lightest gas in the universe exploding that is pure hydrogen this is Ariana a mixture of hydrogen and oxygen and they don't it looks like this much stronger now because of my excellent work.

I have a mixture of hydrogen and oxygen here. I have a fuse that I'm going to make here and this will be my final experiment and we're going to have thunder and lightning. effect here we are going to have thunder, no wonder, sorry, everything is fine, man, let's get rid of this balloon that's getting in my way, now herewe are. I'm going to prepare some flash powder, some flash powder, fusing powder, that's how it will be. to summarize what I have been talking about about chemistry what I have been selling to you chemistry in simple and direct language chemistry for everyone so here we go crossing our fingers and there it is thank you very much thank you very much I really wish you all the best thank you for your kind attention thank you very much really thank you very much I took 15 seconds on the bus we are still in one piece I wish you thank you very much better thank you very much really thank you