chemical reactions are some of the most important processes on earth after all without them life would have never developed and there wouldn't be the compounds necessary for our survival some chemical reactions are exciting to witness that in mind don't forget to put on your safety goggles and stand back as we take a look at 15 incredible chemical reactions number 15 cesium and water most of us in science class will have seen what happens when a small piece of sodium is placed into a tank of water in a short period of time it begins to violently react and if you're lucky it may even explode but sodium is only second on the list of the alkali metals and if you look further down the periodic table you'll see that cesium with an atomic number of 55 is fifth it's actually the most reactive of all the metals while it has a range of uses such as medicine industry and in scientific research the best way to use it is to throw it into water and see what happens in a similar way to sodium when you cut into cesium which is remarkably soft you'll see it instantly react with the air and bright and shiny surface becomes dull and tarnished when it's added to water though the reaction is virtually instant and it's something that should only be done under controlled conditions with experts it produces a huge amount of heat will shatter most containers that this happens in and is over in an almighty bang while it's visually spectacular the speed of the chemical reaction it causes is also lightning quick by adding the cesium to h2o it produces cesium hydroxide and large amounts of hydrogen gas which explains the violence of the reaction the flammability and the power and pressure that it creates number 14 briggs rauscher oscillating clock the briggs rauscher oscillating clock is a surprising experiment that shows that even when you think a reaction is complete it may still have some way to go as an oscillating reaction the volume of each substance in the reaction is constantly changing and this gives the impression that it keeps going backwards and forwards before it's finished to create the effect you need three colorless liquids potassium iodate a mixture of melanin acid and manganese sulfate monohydrate and finally some hydrogen peroxide with the potassium and iodate already in a beaker that's being mixed the second liquid is added and then the third and the mixture will soon begin to turn amber in color suddenly it'll turn to a dark blue but this will then strangely begin to change back to amber then blue again and this will repeat for up to five minutes before settling on the dark blue that smells of iodine the reason why this happens is that the process that sees it turn blue and produce free iodine is only able to take place when there's a low concentration of iodide as more iodine is created the secondary process turns it into iodide which means that the first process stops and the liquid turns amber again at this stage all of the iodine has been used up so no further iodide can be produced and when its concentration has fallen low enough the process to make iodine begins again and the liquid turns blue once more in theory this can continue happening for as long as there's enough of the constituent solutions remaining in the beaker and it's a fascinating example of two reactions taking place at the same time which directly impact the performance of the other 13 diethyl zinc and air diethyl zinc is a compound made up of zinc at the center which is bound to two ethyl groups it was the first organo zinc compound to be discovered when it was first created in 1848 and is now an important chemical reagent that's used in a variety of applications it is however extremely unstable when exposed to water or air and this has led to a secondary use where it forms a part of self-igniting rocket fuel so to show this effect and the reason why it's so useful in rocketry all you need to do is squirt some of the liquid into the air and it'll ignite almost instantaneously this makes it extremely tricky to store and transport because just a momentary exposure to air or moisture will cause this reaction so it needs to be handled with what's called an inert air technique number 12 red phosphorus and bromine red phosphorus is one of the most common forms of phosphorus that you'll find and on its own is relatively stable there are strict controls surrounding the possession and purchase of a chemical not because it poses an imminent danger to anyone handling it because it's one of the ingredients that's often used for the production of methamphetamine this means it's a lot rarer to see any reactions with red phosphorus which is a shame because it can be used for some incredible experiments probably the most impressive is when it's exposed to bromine or chlorine vapor because in these environments the otherwise inert substance becomes explosive in the experiment all you need to do is put some powdered red phosphorus in a jar and then pour a small amount of bromine liquid in even before the liquid makes contact the reaction begins and will burn up all of the red phosphorus when the reaction is finished you're left with a yellow substance which is phosphorus pentobromide and some yellow vapor that's released needless to say this is an experiment that definitely shouldn't be tried at home bromine in itself is dangerous enough to handle and the gases that are released can be extremely toxic and will cause serious damage if breathed in number 11 nitrous oxide and carbon disulfide the reaction of nitrous oxide with carbon disulfide is often called the barking dog experiment and once you see it it becomes clear exactly why for it to work the nitrous oxide is put into a tube with a stopper at one end a few drops of carbon disulfide are added and then the stopper is replaced and it's mixed together this allows for the vapors to form then when the stopper is released and a flame is inserted an exothermic reaction takes place a blue flame shoots through the tube and there's a sound that's just like a dog barking what's happening here is that a combustion wave is created that travels down the tube and the blue light that's formed is a rare example of a chemoluminescent reaction taking place the nitrous oxide acts as an oxidizer and the reaction creates nitrogen carbon monoxide carbon dioxide sulfur dioxide and sulfur it was first shown in 1853 by a chemist called justice von liebig and was so popular that he was asked to show it a second time during which the explosion was so large that it injured the cheek of the queen of bavaria due to these potential dangers of the experiment it's one that should be done in lab with all necessary safety precautions number 10 thermite and dry ice thermite is a mixture of finely ground metal and metal oxide typically aluminum and iron oxide is often used in engineering because of its controllable explosive properties touching it with a flame will cause it to undergo an exothermic oxidation reduction reaction whereby electrons are passed between two constituent parts and energy is released because the aluminum is highly reactive it creates aluminum oxide and a huge amount of heat but what's strange about thermite is that you don't have to expose it to a heat source to start this chain of events and it can in fact be triggered by something very cold instead like dry ice and this can cause a violent explosion quite why it reacts with dry ice like this isn't fully understood it's believed to be because the initial reaction releases a huge amount of energy that instantly turns the ice to vapor which then condenses around the thermite particles which forms a steam thermite aerosol that explodes when particles are thrown into the air the only other explanation is that it causes the ice to break down into hydrogen and oxygen and it's these gases that cause the explosion when they're ignited by the heat either way it leads to a spectacular effect one that should only ever be done under controlled circumstances number nine elephant toothpaste the elephant toothpaste experiment is visually amazing and it's one of the best experiments that's safe enough to do at home to create the effect you need some hydrogen peroxide liquid dishwashing soap food coloring water and some yeast to start with you add the hydrogen peroxide soap and coloring into a plastic bottle and mix it together while combining warm water and yeast in a separate cup when you're ready the yeast mixture is added to the peroxide mixture and the result is a huge amount of foam being produced that looks just like what you'd expect an elephant to use as toothpaste but why does this happen well the yeast in the mixture acts as a catalyst and this quickly breaks the hydrogen peroxide down and separates the oxygen from it this produces a huge amount of small bubbles which combine with the soap and are filled with more oxygen than normal so it expands extremely quickly if you do this experiment for yourself you'll also notice that the bottle gets quite warm this is because it's an exothermic reaction the foam that's being produced only contains water soap and oxygen so isn't dangerous in itself but we still wouldn't recommend trying to use it to clean your own teeth we are constantly adding more people to the top fives production team to bring you all the best content be sure to subscribe with notifications on and hit the like button number eight pharaoh serpent if you've ever tried indoor fireworks then you're more than likely be familiar with the black snake experiment that produces a long tube of ash but this is simply the safer and less spectacular version of something called the pharaoh serpent which was first discovered in 1821 by using a lump of mercury thiocyanate and applying a flame to it you can trigger a chemical reaction that was described as winding out from itself at the same time to many times its former bulk out of a very light material of the color of graphite there's no doubt that when you see it that the ashes snake that's formed looks like the actual venomous snake of some kind and in many ways the ash snake is equally as dangerous the mercury thiocyanate is broken down into mercury sulfide carbon disulfide and carbon nitride while the main component of the ash is graphitic carbon nitride which is yellow in color because of the toxicity of the gas and the ash that's produced it's only safe to demonstrate the pharaoh's serpent in a fume hood to prevent anyone from inhaling the mercury the black snake versions that you'll find in indoor fireworks boxes are only made up of sodium bicarbonate and sugar so are far safer to be used at home number seven aluminum and iodine you don't normally think of aluminum being a particularly reactive substance after all it's used in a range of construction processes but when it's in the right environment the results can be spectacular to create aluminum iodide the metal can be reacted with iodine by using water as a catalyst for the experiment powdered iodine and powdered aluminum are mixed together and still at this stage they don't interact with one another it's only once a few drops of water are added that things begin to happen and soon there's a vigorous reaction so much heat is produced that some of the iodine evaporates to create a purple plume of smoke and you may even see some other colors forming too if the aluminum starts to burn as well it's the final product aluminum iodide is used in a range of chemical processes and is what's known as a lewis acid which because it possesses an empty orbital is actually able to actively absorb moisture from the air again it's not an experiment that's safe to do at home because of some of the chemicals that are created you most definitely wouldn't want to breathe in any of the purple smoke that forms number six hot ice sodium acetate as we all know water turns to ice at its freezing point if you were to hold it it would feel very cold in your hands but what if there was a way to make ice that's warmer well by using sodium acetate you can certainly create the illusion that this is happening even though you're not technically creating ice this experiment relies on the principle called supersaturation whereby you're able to load water with a large number of crystals which will then collect together and form what looks like an ice formation you probably know that there's a limit to how much sugar you can stir into water but then if you warm the water up you're able to dissolve more sugar into it which will remain there even if the water cools down again that's exactly how this experiment begins by adding sodium acetate to warm water and then letting the temperature drop all you need to do is add a sodium acetate crystal to the cool water and this acts as a nesting site for all of the crystals being held in solution when given the chance they fall out almost immediately and appear to quickly form into ice what's weird is that the process is endothermic so you'll notice warmth being emitted from the liquid which is something completely at odds with what you'd expect when handling something that your brain is registering as being ice number five the halloween clock normally when you mix liquids of different colors together you'd expect them to slowly change color but there are some experiments where the reactions take place so quickly that an entire beaker of liquid will change color virtually instantaneously and almost look like it's a magic trick one of the best examples of this is called the halloween clock or old nassau to do it you need a source of starch sodium metabisulfate mercury chloride potassium iodate and some distilled water already you can see that some of these ingredients are highly toxic so this is definitely an experiment that should only be attempted with the assistance of experienced chemists all of the parts are mixed together in a beaker and the reaction begins straight away to begin with the metabo bisulfate ions react with the water to create hydrogen sulfide ions then these reduce the iodate ions to iodide ions and once these are present in high enough concentrations a mercury iodide solution is produced which is orange in color and instantly turns the whole solution orange things aren't over yet though because a redox action then takes place and sees a molecular iodine being formed and once this happens the liquid turns a dark blue black color instead named after halloween because these are the two colors most associated with the celebration or old nassau because these are the two colors of the house of nassau it's a great experiment to show that even once you've observed to change there still may be other processes taking place that will ultimately leave you with a completely different end result number four nitric acid and copper everyone's familiar with copper it's used in the production of coins and is often used in plumbing and electrical wiring the main reason why it's so common is that it's relatively inert and won't react too much with the environment there are some chemicals that can get a reaction out of copper though one of them is nitric acid the nitric acid causes the copper to oxidize so to start with after it's added the solution is highly concentrated and takes on a green color soon after though this will turn greenish brown and eventually turn blue but this isn't the biggest effect that's caused at the same time the nitric acid is reduced to nitrogen dioxide which is a foul-smelling poisonous brown gas that gets released in a large plume as you can see in the experiment the beaker is soon filled up with the gas and is carefully extracted because if anyone were to inhale it it'll cause some serious health problems it's an experiment that's often shown at science demonstrations to highlight how even what seems like an unreactive substance can produce something highly toxic and dangerous that's the reason why the commercially available products that contain nitric acid will always have warnings on them about letting it come into contact with copper and other metals number three sodium and chlorine the next time you sit down for a meal you probably won't think twice about adding some salt to it it's a common type of seasoning that's used around the world and we hardly even think of it as being a chemical but its formula is sodium chloride and it's made from two highly reactive elements sodium as you probably know violently reacts when it's added to water and chlorine was used in the first world war for chemical warfare most salt that we use has formed naturally but if you want to create it in a lab the reaction is surprisingly violent to do it you need to fill a flask with chlorine gas and one way to do that is by reacting hydrochloric acid with potassium permanganate once this is done a couple of pieces of sodium are put into the flask and a few drops of water are carefully put on top of it the result is a bright flash and an exothermic reaction that produces a white smoke that's full of sodium chloride dust which could then theoretically be collected and formed into salt crystals the only question is after seeing all the chemicals that went into making it would you feel comfortable putting salt that's been made this way on your fries number two nitrogen try iodide and touch nitrogen tri iodide is a highly unstable inorganic compound it has an extremely complex structure that scientists don't yet fully understand because most techniques of studying it aren't able to do so safely enough first discovered in 1812 the more common way of making it is by reacting iodine with ammonia and when this is done at a low enough temperature in anhydrous ammonia it creates stable and usable nitrogen triiodide the reason why it's relatively unstable though is because its chemical composition involves a small nitrogen atom at the core and three iodine atoms held very close to each other they're basically looking for any excuse to break these chemical bonds and the first chance they'll get they'll take all you need to do is gently touch nitrogen tri-iodide and it'll explode with a poof of purple smoke but beyond being amazing to look at there are very few practical uses of it this is because it's simply too unstable to be used in controlled explosives even nitroglycerin which is similarly shock sensitive can be altered to be safer to handle but there's so far no similar process that can be done to nitrogen tri iodide to demonstrate just how delicate it is you don't even need to touch it with something of significant weight a feather is enough and so is a slight breeze the light of a laser and even a quiet sound wave and it's also known as the only chemical explosive that detonates when it's exposed to alpha particles and other products of nuclear fission number one dancing gummy bears gummy bears are undoubtedly one of the most fun treats you can get but there's a reaction that can make them even more entertaining imaginatively called the dancing gummy bear experiment it's possible because of the high sugar content of the sweets and this is one that must only ever be attempted with the assistance of experienced chemists it goes as follows an ignition tube is filled with a small amount of molten potassium or sodium chlorate and the brave gummy bear is dropped on top almost immediately it produces a huge amount of purple smoke the gummy bear can usually be seen violently jumping up and down inside the tube and then there's a bright light as the gummy bear is fully consumed by the reaction rather than one process happening there's actually a series of things going on here at first the potassium chlorate is melted which is an endothermic process and then this molten potassium chlorate begins to decompose which releases oxygen this at first produces potassium perchlorate which then breaks down and then allows for the sugar inside the gummy bear to undergo rapid oxidization which produces carbon dioxide and water along with a huge amount of heat and light the purple smoke has nothing to do with the gummy bear but is actually the remnants of the potassium it's a great experiment to demonstrate the energy that's stored within sweets and any other products that have large amounts of sugar in them in theory it would work with any type of candy but there's something that just seems right about using gummy bears to demonstrate the effect watch our binge watching playlist if you'd like to watch all of our most popular top 15 videos grab a drink grab a snack and get ready to binge you