Justonium

I calculated the energy stored per mass of disk of two discs of different sizes, both spinning at speeds with equal centrifugal force upon the outermost layers, and found that whenever you double the radius of the disc, the amount of energy stored per mass of disc also doubles. I'm too lazy to show all my math here, but basically, I just used integrals to calculate the total kinetic energy of the discs and then just divided by the mass of the discs. So if a disc shatters close to around when some part of the disc has a certain maximum centrifugal force acting upon it, as I have assumed, then the larger your disk, the more energy can be stored per mass of the disc's material. This could probably be increased by having the disc be hollow, and maybe having some kind of spokes to hold them together. Merged post follows: Consecutive posts mergedinsane_alien, The circumference of the steel ball is traveling at 960 meters per second, whereas the circumference of the earth is traveling at a mere 460 meters per second. You're energy density for the earth came out to be 2 orders higher than that of the steel ball, but that can't be right. When comparing two similar rotating bodies of the same material, energy density is proportional to the velocity of two corresponding points in the bodies. So assuming the earth and the steel ball are about the same density, the earth should have about half the energy density of the steel ball, because its circumference is moving at roughly half the speed of the ball's

Kk, I've calculated the relationship between kinetic energy per mass and radius, assuming both discs are traveling at speeds where the centrifugal force exerted on the outermost layers are the same. Kinetic energy per mass and radius are directly proportional. So assuming a disc of a certain material will shatter when a certain constant centrifugal force is reached in the outermost layer, the amount of energy possible to store in a given unit of mass of the disk's material is directly proportional to the radius of the disk used.

I still need mathematical proof of this. I will attempt to calculate the trend by comparing 2 discs of different radii and assuming they will burst when the centrifugal force acting on the outermost layers are the same. Using integrals, I will see which one has the higher average inertia per mass when the centrifugal force on the outer layers are equal, but I might be unable to figure out the answer.

Mr Skeptic, are you sure there would be a limit to the sized disk that would be most efficient? Either there is, and this would vary for different materials, or there isn't and the efficiency increases the bigger you get no matter what; this is what I want to be certain of.

I'm not talking total energy, I'm talking energy density. The earth weighs a lot compared to the energy stored in its rotation. The earth would probably have much lower energy per mass than a .8mm steel ball going at 23 million rpm. Sorry if I was unclear. Merged post follows: Consecutive posts mergedBasically, what I want to know is this: when comparing 2 disks of different diameters, both spinning at speeds at which the outer layers of each one have equal centrifugal acceleration, which disc's atoms will have a higher average velocity squared? I'm a noob at physics i know. Argh, the centrifugal acceleration of the outer layer of the disc wouldn't accurately represent the stress pulling the entire disc apart. This is a complicated problem.

The technology to store and release energy from a spinning ball already exists; it uses similar principles as an electric motor and an electric generator. By the way, I see a lot of people saying the bigger it is, the more energy storage, but I disagree, because a very large sphere would have incredible centrifugal force that would tear it apart when the core of it would be traveling at relatively lower velocities. I know that once you get really really big, gravity takes over and holds it in, but is that is irrelevant in this thread because it is not practical to use here on earth.

Yeah, I understand that the limiting factor is the strength of the ball to hold itself together; I'm just saying that I wonder what size of a ball would have the maximum possible energy density in it's inertia before shattering. Too big of a ball would make the centrifugal force too great to hold in at too low speeds. By the way, what I mean by energy density is the kinetic energy per mass of ball. Also, if the optimum radius is known, this would best be taken advantage of by using a rotating cylinder, because that radius would be present everywhere. The reason I brought this topic up is because I'm wondering if a spinning object suspended in vacuum could make for better energy storage than the currently used chemical batteries. It would also be a lot more convenient to store and release energy, and would never degrade.

Thanks, now I can read up on that experiment. Merged post follows: Consecutive posts merged The farthest point from the axis; I'm kind of curious to see the fastest man can make a significant amount of matter travel in circles in a small space. And now that I know it was .8mm in diameter, I can calculate that the fastest part of the steel ball was traveling at a linear velocity of.... ohmyghosh, only 960 meters per second. I wonder what size ball will allow the greatest energy density to be stored in its inertia without destroying the ball.

Somebody said 23 million rpm done on a steel ball in a vacuum on yahoo answers, but I couldn't find the statistic myself. What do you mean about radiation? Like atoms flying off due to extreme centrifugal force? Oh, and sorry, yeah, because I couldn't track the 23 million rpm statistic I can't get the radius of the ball to calculate the linear velocity. I wonder what the max linear velocity ever achieved is. Gosh it would be a disaster if one of the balls used in these experiments reached a speed high enough to rip itself apart.

Apparently the fastest an object has ever been made to spin is only 23 million rpm. What is preventing us from making things spin faster, and maybe even approach the speed of light? If an object is magnetically suspended in a vacuum, I see no limiting factor. The only objects ever made to approach the speed of light have just been subatomic particles spun around a circular circuit of tube. When spinning an object with significant mass, however, the circuit of tube poses a huge limit to speeds attainable because the object's centrifugal force would be to great to hold in, but if it is spinning stationary, I see no limit to how fast electromagnets could accelerate it.

BOMBS ARE DANGEROUS. Alright, if you've ever wondered if you can make a bomb with sugar, yes you can! I just made one and it was pretty good. It sounded like a gunshot, and the tin it was in didn't land for a while after the explosion. For anybody who is interested, here's my mix: 35% sugar, 63% potassium nitrate, and 2% red iron oxide. I have never heard of anybody else using this as an explosive, but, sure enough, it worked! Far cheaper than making black powder (not to mention much easier to obtain the ingredients and make). Just putting this information out there for people to use. I have purposefully left out how to make a bomb with this formula, so if you don't know how to do that, then you shouldn't be making one! Oh, this might also work without the iron oxide, but it will be much less reliable, as the ignition temperature is much higher, and the pressure at which a runaway reaction occurs will be so high it might not be obtained in many setups.

I don't know anything about what you're doing, but sodium bisulfate acts like sulfuric acid when dissolved in water.

K, its urea then.

When it was cold, it smelled very faintly of ammonia, but nothing compared to when I heated it. I didn't test it using hydrogen chloride when it was cold though, but it would most certainly have made white mist, because there was enough ammonia for my nose to detect. Note, it did not originally smell of ammonia, and only did after several days of sitting in sodium hydroxide solution. Could urea possibly hydrolize at room temperature very slowly? Anyway, assuming my solid was indeed urea, it would have completely hydrolized upon heating, liberating carbon dioxide that would have then immediately reacted with the sodium hydroxide to make sodium carbonate. That is what I would guess was the solid left behind. Thanks for the info suggestions UC. I also know that there was no sodium hydroxide left in the solid because it was not hydroscopic. This makes sense because I mixed the proper amounts of the (possibly) urea, and sodium hydroxide to stoichiometrically react to make sodium nitrate (I had thought I was handling ammonium nitrate. The same mass of urea would react more sodium hydroxide than would it's equivalent mass of ammonium nitrate.

Oh, I forgot to mention, I did another test for ammonium ions, and it was positive. I just reacted it with sodium hydroxide and it bubbled ammonia gas which formed a white ammonium chloride mist with hydrogen chloride gas. Thanks for the info, guys. OK, I'm pretty sure it's urea. What does urea dissociate to in water? I've reacted the urea with excess sodium hydroxide and boiled off all the liquids, and have gotten a yellowish white solid. The yellow may, however, be due to the sodium hydroxide reacting with an unfortunate fly that I found had landed in it. Is this new salt possibly sodium cyanate?

OK. I've done some experiments and have determined that the chemical equation for synthesizing sodium by reducing from its hydroxide using magnesium is: 2Mg + 2NaOH --> 2MgO + 2Na + H2 This reaction is very interesting, because a more electropositive element is being reduced by a LESS electropositive element. It happens because the magnesium is reducing both the sodium and the hydrogen in sodium hydroxide, making it exothermic. It is also dependent on the fact that the lattice energy of sodium oxide is less than that of magnesium oxide. This is because sodium ions have a smaller charge than magnesium ions, decreasing the lattice energy and making this reaction possible. If sodium oxide were more stable, the reduction would stop after hydrogen. If you still don't understand this reaction, let's break it up to better represent what is going on. Mg + 2NaOH --> MgO + Na2O Mg + Na2O --> MgO + 2Na These 2 equations add to get the total equation shown above. If you're wondering what my source is, I looked enthalpies of all these compounds and puzzled with the possibilities on paper, and determined that equation, and then verified it by making half a gram of sodium using this method. All the predicted products were created. The hydrogen burns yellow as it comes off because of sodium ions present in it. The reaction was so hot that it heated my brand new crucible to nearly 1,100 degrees celcius (orange-yellow color) and cracked it in half. Better get a new crucible.

It came from an instant cold pack (so it's enthalpy of dissolution is pretty high.) It utterly failed a test for nitrates, melts into a clear liquid under the heat of a blowtorch, and decomposes upon further heating to form a steamy gas and a white compound with a very low solubility in water. (No the cold pack did not say what was inside it besides the water pack.)

Well, charcoal is the fuel, so it wasn't reacting with the magnesium; sodium nitrate is the oxidizer, but I know for a fact it doesn't spontaneously react with magnesium; sulfur becomes sulfide to allow more oxygen to leave the nitrate, and I have considered that it might form a sulfide with magnesium, but I tried mixing magnesium and sulfur powders and nothing happened. I can't figure out what this reaction would be but it seems logical that it involves both the sodium nitrate and the sulfur. My powder was also slightly damp, so I should really go test magnesium with sulfur and sodium nitrate again with a little water added to really eliminate those possibilities.

I had some black powder containing charcoal, sulfur, and sodium nitrate, which I added some magnesium powder to. After mixing, I started to compress some in preparation for ignition, but as soon as I started to press it together, it became suddenly warm. Yikes! What is the magnesium reacting with that is causing this to happen? BTW, the amound of powder was very small so don't worry about me blowing myself up. When you experiment with explosives, ALWAYS START SMALL!

The edge of space is not a tangible place. No matter how fast you travel, you can never get there. The edge of space is basically at the end of where anything can possible go. With every passing second, matter and energy in the universe have the time to travel farther, so space expands accordingly at the speed of light. Space is where stuff exists. You can basically think of the expansion of space as the expansion of where the stuff created in the big bang has a possibility of existing at any moment.

I know this thread is old, but I want this here for viewers to see: The best ways to make sodium nitrate from ammonium nitrate are to react with sodium carbonate or sodium bicarbonate. Much cheaper and less dangerous than using sodium hydroxide. Sodium carbonate is my favorite method because less is required, and because it makes a bit less gas bubbles when mixed with ammonium nitrate. Ammonium carbonate also has a decomposition temperature of about 20 degrees Celcius colder than that of ammonium bicarbonate, making me more confident that all of the byproduct has been decomposed. Also note that washing soda is a monohydrate, and that affects its molar mass. reactions: with baking soda: NH4NO3 + NaHCO3 --> NH4HCO3 + NaNO3 NH4HCO3 --> NH3 + H2O + CO2 with washing soda: 2NH4NO3 + Na2CO3 --> (NH4)2CO3 + 2NaNO3 (NH4)2CO3 --> 2NH3 + H2O + CO2

I understand that we have to be careful in this type of thread because everything we say is open for the public, and for stupid kids to try and blow themselves up, so I cannot go into any details, but I will say this: It is possible to synthesize moderately pure sodium using no electricity, and using only washing soda, pickling lime, magnesium pencil sharpeners, and rudimentary tools commonly found in the kitchen and the garage. It's not safe without proper safety equipment, but I'm just saying, it's not impossible to synthesize sodium in you're backyard if you know what to do. By the way, sodium bought from sites like United Nuclear is outrageously overpriced because of its dangers, so yeah, I'll just make my own. You can really tell that it's overpriced because it's way more expensive than lithium LOL.

Today I burned an alloy of magnesium and zinc I had made, and to my surprise, little blobs of oxide grew on it as it burned, and started floating away in the wind. It burned much less violently than pure magnesium metal, just glowing bright red-orange and making the blobs (opposed to making the standard powder and wispy fumes seen when burning pure magnesium). I saved some of the white oxide material, and when I look at it, it shows slightly bluish through the white, just like aerogel does. When I held it up so that it was illuminated by the ceiling light from behind, it appeared to glow orange. It is very light, and has such a weak structure that it can be compressed by the slightest touch. Does anybody know where I can find any information on growing sol-gels by burning metals? I assume I'm not the first to do this.

I suggest hydrochloric acid (lots of toilet cleaners have it). Just wear gloves, keep the room ventilated, and don't spill it on anything organic. I use it to dissolve all kinds of metal oxide or carbonate stains on my glassware.

Lol, I accidentally made some gaseous metal yesterday. Look at the thread 2 below yours, titled "What caused this explosion?" if you're curious.