Don’t just think that this is another howto where I am going to tell you people how to install/configure something so that after reading this you will be able to make a hollow iron sphere 😛 Actually, a lot of discussion has gone on how to really come up with a hollow iron sphere that is perfect.
We all went to SE class as usual. After 20-30 minutes, I got bored and was in a frustrating situation. I need not stay in the class but I could not come across a better way to kill time. Suddenly, this question came to mind “How one can really make a perfect hollow sphere?”. Pankaj was sitting next to me and I fired this question at him thinking that it would kill some time and may be in the meantime lecturer can catch us talking and throw both of us out of the class 😛 (didn’t really mean it, but for the sake of writing one can exaggerate).
Definition of perfect hollow iron sphere
A perfect hollow iron sphere is a sphere which is hollow from inside and there should be no hole through which air can pass from the core to the outer space and vice versa. The inner surface should be perfect with no deformations. The constraint is that you can’t join two hollow hemi spheres and make a hollow sphere out of it. After you have the hollow sphere, there should be absolutely nothing inside the hollow part (e.g. some material or whatever. air is permitted.).
Solutions
Pankaj tried really hard and proposed different solutions for making a hollow sphere. But none of them could really convince me and he can’t come up with an idea to make a hollow iron sphere. Sambhav and Ankush was sitting just in front of us. Pankaj shared the *million dollar problem* with them and asked them to come up with a solution. Pankaj thought that these guyz are nine pointers and may help him. But it was really disappointing that even they could not come up with an idea that can help us build a hollow iron sphere. Then the question was forwarded to Kiran, Deepak and Rishi as well. But everyone was equally disappointing. Below are some solutions proposed.
1. First solution was proposed by Pankaj that we somehow make two hollow hemispheres and then join them to make a hollow iron sphere. But this solution violates the definition of a perfect hollow iron sphere. So rejected.
2. Second solution was proposed by Pankaj again that we make a thin hollow sphere by beating an iron sheet and later deposit layers of iron on it. But this is practically impossible because when you will try to deposit the molten iron on the thin sheet, then the sheet itself will melt. So rejected.
3. Third solution was proposed by Sambhav that we make a ball of wax and put it in a container containing molten iron. We will leave a hole in the iron part so that wax can come out on heating to high temperatures. Now, I really doubt these guyz with high CGPAs. Can you ever think of this idea? This is like committing a suicide if inteviewer happened to ask that quesiton in your job interview. How can you think that wax will be solid at melting point of iron 🙂 So rejected.
4. Fourth solution was proposed by Ankush that we make a ball of clay and then we deposit iron layers on it and then we again cover it will a layer of clay. Now, I don’t really get what he was trying. Again a high CGPA victim. I think he was trying to make a hollow sphere of clay(?). So rejected.
Hint
You can’t use a material for the core whose melting point is higher that iron because you will not be able to remove it from the core once you deposited iron layers over it. You can’t even use a material for the core whose melting point is lower than iron because when you put molten iron over it, the core will melt and you’ll never have a hollow sphere. Just keep thinking.
While these people were putting forward there solutions, I was cursing them. I said that you people are now studying at undergraduate level and still you don’t know how to make a hollow iron sphere. This discussion lasted till the end of SE class and they could not come up with a solution. And if you are still reading this post, I think you are also curious about this question and dying to know the solution.
I have to say that this question is still mystery for all of us. Even I don’t know how to make a perfect hollow iron sphere. And by any chance or coincidence if you know the solution, please please leave the solution in the comments or give me a link.
PS1 : BTP report and presentation went fine. Profs were impressed 😛
PS2: Looking forward for summer vacations as an opportunity to get into a new world 🙂
PS3: Writing crap these days.
PS4: My earning on Google adsense crossed $10. So, I have got the money back that I spent on buying this domain 🙂
Asshole…. M*****F*****….BC….teri g*** mein itna bada danda karoonga na…salle.. I was literally hoping to get the answer from you 🙁 and even while writing my post I was thinking about this ‘4 anna ka question’ …. but nicely written 🙂
I guess this should do it, though am not completely sure if it’s possible.
Take a spherical shape of some material with some sort of acid embedded in it… thinking of something like a fire extinguisher. The material should melt and form some gas when mixed with acid (you didn’t specify that hollow means vacuum or any other gas 😛 ) and also have a melting point greater than that of iron. There you go… something to mold upon. 😛
Of course, now you need to find this special material… maybe some ceramic material will do? 😛
@Pankaj sorry dude … i don’t have any solution .. i just asked you some random question. i think i do it frequently … its nothing new 🙂
@Gagan you can’t cheat. Come up with the material 😛
Well, it isn’t difficult. 😛 You need some ceramic that has a higher melting point than that of iron (1538°C).
I found TiC to be one such ceramic element. 😛 (source: http://www.a-m.de/englisch/lexikon/schmelzpunkte.htm )
But finding an acid that can react with this thing seems a hard job.
PS: I’m glad you didn’t notice the fact that the acid might react with the iron. 😛
interesting.
see these –
http://www.google.com/patents?id=KtwlAAAAEBAJ&dq=5693269
http://www.google.com/patents?id=ycFkAAAAEBAJ&dq=3534926
“And if you are still reading this post, I think you are also curious about this question and dying to know the solution.”
Yawn!
Take a hollow iron sphere and put an iron layer over it. Recursive procedure defined below:
1.Get a hollow iron sphere.
2.To make the first hollow sphere, go to first step.
3.Put an iron layer over it.
End condition: when you will be able to reach to size of sphere equal to that of a molecule of air/gas(oxygen, CO2 on convenience)
@gagan you are quite intelligent and curious to explore new things 😛
@karan sry dude!! ok.. let me rephrase the sentence “And if you are still reading this post, I think either you are also curious about this question and dying to know the solution or you are a frustoo who doesn’t have anything better to do in life.” does that make sense for you 😛
@Sukesh by this method you can’t make a generalized hollow iron sphere. you’ll have hollow iron spheres whose inner radius will be equal to the radius of an atom or molecule of air/gas. which is more of less like a complete solid sphere. Think better 🙂
Bah!! This is cheating.
you didn’t mention “generalized” earlier.
Anyway I have a solution:
Now that you have got a sphere with inner radius of CO2 molecule size.
You will have to heat it to just below iron-melting point under high pressure (high pressure needed because gas molecule will expand at high temperature so may cause explosion of our iron-ball).
Once iron is soft enough (like wet flour) we release the extra pressure to give way to CO2 molecule to expand. Now at this point gas will expand and with that iron sphere also being soft now. You can regulate pressure till you get intended radius.
Analogy is similar to how our mothers prepare “fluffy” rotis. IIIT mess has made you guys forget real simple things 😀
Draw a sphere in openGL or Direct3D or whatever u like and then texture map it with iron texture… so simple 😛
@Sukesh… Gas molecules don’t expand… Its the intermolecular distance that increases on heating 😛
So ur single molecule isn’t going to expand…
if gases are permitted..
Take a vacuumed room in a gravity free environment with a heating device attached. Something like a oven maybe.
let an iron ball be suspended in the room. Increase the temperature to heat the room. When the iron ball is in liquid, inject some (some here is dependent on the size of the ball) air into the ball.
Since there is no external force on the ball, everything will be perfectly round. Inner walls, outer walls and the radius will also be constant.
@Sukesh as ZenWalker point is valid. so you solution is still wrong.
@ZenWalker thanks zenwalker for the solution and for pointing out the mistake in sukesh’s solution as well.
@Rao this sounds interesting but it can be accepted if some more people vote for you 🙂
@all smr’s comment was marked as spam … i just approved it. makes an interesting reading 🙂
@Rao: How exactly are you going to suspend the ball. That’s my only doubt. 😛
One way we can use this vacuum thing and stuff is by observing the property that a falling drop has a spherical shape. If I drop liquid iron from enough height so that the iron solidifies before reaching the ground, I can get hollow spheres. (Vacuum because otherwise the drops will take tear shape).
I’ve thought of 5 other methods to solve this problem. I guess I’ll post them in my blog when I get time. 😛
“@Rao: How exactly are you going to suspend the ball.”
Easy. Melt some iron. put it in a syringe of some sort and slowly push it out of the syringe. When the last “contact” is leftjust have a wire or a fast moving blade to cut off the link.
@Rao are you copying it from one of the patents that smr has mentioned in his comment 😛
Hello, I have the answer juz visit this(www.metacafe.com/watch/417094/make_a_cute_and_sexy_little_sphere) link and u will knw. Easy to prepare a hollow iron sphere. but it need great people to do that…
@vendi wtf 😛
I’m sure everyone has moved on since the copyright here expired a few years ago, but… you can plasma coat iron onto materials with a lower melting point than iron without deforming the mold and only having microscopic surface impefections (far better than most castings). So:
1. Make a sphere of ice as perfectly as possible (likely molding and refining).
2. Plasma coat with iron.
3. Build up a suitable iron shell.
4. Heat the iron shell for a good long time but keep it below it’s melting point.
5. Surprise, surprise the water will leave and be replaced by air BECAUSE no container, even a “perfect iron sphere”, is perfect! The water/steam will escape through the metal over a long enough time. Try saving a Coke can in your attic for a few years.
Heating just helps speed things up but isn’t required. Yes the water may/will rust the inside and I don’t think cathotic protection will work since free electrons will move to the outside of the sphere. Smaller is better as the time to empty and surface area to volume will lead to less opportunity for rust.
Alternately use a core that won’t rust it, perhaps glacial acetic acid as I doubt it will rust iron and can be vaporized until it escapes.
Another idea. Make a ‘perfectly’ spherical mold out of two partial hemispheres of conductive metal and the equator made of a non-conductive material. It’s key that all 3 parts mate perfectly so the interior of the mold is a perfectly smooth sphere. Connect a thin iron wire to the inner poles of each hemisphere so that when the mold closes it runs from one to the other. Close it and apply a large electric current across the hemispheres. The iron will vaporize, spread outward radially and coat the inside of the mold: perfect… at least until you destroy it by opening the mold. Nobody said you couldn’t leave the mold material on the outside though.