The Strength of GRAPHENE Explained

[Music] subjects zero here so how do we know that graphene is really strong this one question has been answered a while ago but nobody seems to get it right or worse no what it conveys and what I mean by that is that you will often hear people saying that it's either 10 times stronger than steel or sometimes 200 times stronger than steel like there's a lot of misconception here and to tell you the truth they are both right but zero how can they both be right and the answer is it's a matter of reference first you must understand how they figured it out this strength of the graphene and to do that what they basically did was to shoot it like really they literally shot graphene and you know a graphene sheet no not with a gun but with a micro gun for what they called micro ballistics this is nothing more than a membrane to which they attach a micro bullet made of silica balls when the membrane expands the tiny bullet flies through space in speeds over a thousand meters per second just for reference the fastest bullet reaches speeds of about 1250 meters per second however this is the fast as you can get but normal bullets are well below that speed or about 762 meters per second the idea here is to calculate how much energy it is needed to break the graphene by acquiring the speed before impact and after impact by knowing the difference in speed they can calculate the kinetic energy transfer or loss in the process and by that we can tell how strong graphene is and compared with other materials in this case what you're looking for in a strong material is its ability to absorb impact among the other things for instance when compared to steel in an equal weight basis and when I say equal weight I mean like one to one in example like one gram of graphene against one gram of steel graphene is ten times stronger however this is a bit misleading for a few reasons it's not that with ten times less material you can't achieve the same thing is that in this experiment the bullet that is shot at both materials at the the bullet lost 10 times of its speed or kinetic energy in comparison from one to another but because of the simplicity of this experiment you won't get the entire picture of how strong a material really is simply because you have other characteristics that can be way better and that my fellow subjects is where you get the 200 times from and then you might be thinking so zero what is the 200 times stronger all about and the answer is the tensile strength by definition the tensile strength is the resistance of a material to breaking under tension stainless steel has a tensile strength of 505 mega Pascal's while graphene has a tensile strength of 130 Giga Pascal's divide one by the other and you get more or less 257 times stronger than stainless steel just for the comparison Kevlar is 375 point 7 mega Pascal's and if you compare to carbon steel which has a tensile strength of 370 mega Pascal's it's even more but a true comparison would be galvanized steel which was used in the Golden Gate Bridge and it has a tensile strength of about 600 mega Pascal's which will give you about 216 times stronger that's why they say it's over 200 times stronger than steel so just for you to quickly picture this the diameter of the Golden Gate Bridge cable is ninety two point four centimeters comprised of twenty-seven thousand five hundred seventy two wires as each wire is about 0.40 eight centimeters in diameter each of those wires can individually hold eight point eight kilograms per meter now the kicker according to one study of 2008 called measurement of elastic properties and intrinsic strength of monolayer graphene they concluded that the breaking strength of graphene is about 42 Newtons per meter so I will assume here that they are using a sample of 1 meter by 1 centimeter by 3.7 angstroms graphene sample to make my calculations so if the cable in the bridge can hold about 60,000 tons per Anchorage or 600 million Newtons means that we would need about fourteen million two hundred eighty five thousand seven hundred fourteen layers of graphene which gives us a cable with cross section area of 0.5 T two centimeters squared like whoa this is mind boggling we are talking about a cable that is twelve thousand eight hundred ninety four times less area when compared to the Golden Gate Bridge cable cross section of six thousand seven hundred five point 54 centimeters squared like holy crap that is absurd just to think about it and it is it even possible well I guess we will find out if these scientific measures are right because to be honest it is hard to picture this like is it really that strong well this question actually makes me more excited for the graphene revolution alright folks that's it we're done here [Music] [Applause]

Channel: Subject Zero Science

Views: 131,789

Rating: 4.8977275 out of 5

Keywords: how strong is graphene, graphene technology, graphen, graphene armor, what is graphene oxide, graphine, graphene test, graphene strength test, graphene sheet, what is graphene, grafen test, graphene vs bullet, graphene, graphene production, graphene applications, elon musk, graphene properties, what is graphene used for, what is graphene made out of, what is graphene battery, how strong is graphene compared to steel

Id: hvonBXvhCc4

Length: 5min 30sec (330 seconds)

Published: Sat Jul 28 2018