字幕表 動画を再生する 英語字幕をプリント (Intro) (Warning) Hello everyone! Today I want to tell you about such element as oxygen and show its properties along the way. I think many of you already know that oxygen resides in the atmosphere and is essential for life, and is also involved in the combustion process, i.e. oxidation. Oxygen is the most abundant element on Earth, our atmosphere contains only 21% of oxygen. The remainder of the oxygen on Earth is distributed in the form of compounds - that is oxides, carbonates and water. We have all seen that lots of different things can burn down in oxygen such as wood, paper and plastic. Though if we increase the oxygen concentration then things start to burn quite more intensely. Also, like any gas, oxygen can be condensed, i.e. liquefied. For the condensation of liquid oxygen we've used liquid nitrogen. The boiling point of liquid nitrogen is 13 degrees lower than that of oxygen, so by passing pure oxygen from a cylinder through a copper coil that is cooled by liquid nitrogen we can obtain liquid oxygen. The oxygen liquefaction itself looks very fascinating. (it's so beautiful) Fun fact - in large hospitals oxygen is normally stored in liquid form in large tanks to save space and for easy transportation. And we've obtained the liquid oxygen, let's look at its properties. The most interesting fact is that in liquid state oxygen is not a transparent liquid, it's in fact blue! All because of the light absorption spectrum of oxygen atoms. Also, liquid oxygen is paramagnetic and is attracted to magnets, by looking closer we can see small droplets rising towards the magnet. For the experiments with oxygen, we took a sponge, toilet paper, chips, tea, T-shirt, crackers and a few other items. To begin, we take a dry crust of white bread and try to burn it at normal oxygen concentration in the air. As expected, the bread does not want to burn. Now let's soak it with liquid oxygen and try to ignite it again. (rip bread) The liquid oxygen dry bread turned into a real jet cracker... ...even gave little traction. If we add some more oxygen to the smoldering cracker it starts to burn again. Now let's take a toilet paper and soak it in liquid oxygen and then set it on fire. (rip toilet paper) I think we have just created a new kind of rocket fuel out of toilet paper. In fact, in the rocket engines of Shuttle liquid oxygen served as an oxidant and liquid hydrogen was the fuel. Unfortunately, we don't have any liquid hydrogen, however, look at this lovely tea bag! In the cup filled with liquid oxygen it doesn't want to brew (meaning we won't have any liquid oxygen tea today), however in the subsequent ignition it then turns into a real powder. (rip tea bag) Also, if you soak a cotton T-shirt in liquid oxygen and ignite it, it will turn into a real bomb! (rip T-shirt) DO NOT ATTEMPT TO REPEAT WHAT YOU HAVE JUST SEEN! From the close contact of oxygen molecules with the T-shirt material, its combustion is magnified. The same thing happens with a cotton wool... (rip cotton wool) ...as it absorbs oxygen very well and has a large surface area of the particles. Though the most rapid combustion reaction with liquid oxygen was acquired with an ordinary kitchen sponge. (rip kitchen sponge) The soaked in liquid oxygen sponge simply disappeared when it was ignited without even leaving a piece of it as a memory. If you like chips, think of how bad they can be for your health, how much fat and harmful substances is contained in them. It is better to throw them away, but wait, they contain a lot of energy! With the addition of liquid oxygen all the energy contained in those chips breaks out in seconds. (rip chips) During the combustion of chips, as well as everything before them, carbon dioxide is formed and hydrogen monoxide (which is water in the form of steam). Also, for those who don't have strong positive feelings towards oat porridge, we have specially soaked it in liquid oxygen for you, and ignited it to show you how much energy it contains! Oatmeal is not only full of beneficial vitamins and minerals, but it also energizes you for the whole day! Also, if we lower burning sulfur into a flask with liquid oxygen, it will light with a very beautiful blue flame. It looks absolutely glorious. As a result of this reaction, oxygen and sulfur have formed sulfur dioxide. And finally, we decided to burn iron. Everyone knows that iron does not burn in air. But if you make it into more like thin chips of wool, and set on fire, it will burn well. What can we say about liquid oxygen? Adding steel wool to it will make it a real lava - burning in seconds and turning into iron oxide. From the heat of the reaction, the steel saucer even melted. Oxygen in nature typically exists in gaseous form and in low concentrations that save us all from the fire randomly appearing everywhere if there would be more oxygen. Oxygen has a two-atom molecule, but there is one other molecule that consists of 3 oxygen atoms! That is ozone. Such a phenomenon is called allotropic modification. In the troposphere, we don't have much ozone. and it's mainly found on a higher altitude. The ozone layer protects us from the strong ultraviolet radiation coming from the sun. Without it, our eyes would have ceased to see in a couple of hours. The retina would have simply been burned and life on Earth would be pretty much impossible. Also the molecules that make up our body contain a lot of oxygen. In our body, it has the most presence if we compare it by mass. Oxygen is produced from photosynthesis in plant cells. Think about it before cutting down the trees! 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B2 中上級 酸素 - 地球上で最も豊富な元素! (Oxygen - The MOST ABUNDANT Element On EARTH!) 26 0 Wongwl に公開 2021 年 01 月 14 日 シェア シェア 保存 報告 動画の中の単語