elementcollector1

For galvanic cells, the anode is negative and the cathode is positive. For electrolytic, the reverse is true.

Maybe not across the room! Just enough to exert a force on an object without touching it. While I read the page, I don't come across much to do with such low-density 'projectiles' as plasma, and wouldn't it *not* have a fixed volume, length or anything? Hmm. So, I guess the analogy was imperfect - but then why does the plasma in a railgun accelerate in a specific direction? If the voltage constantly reversed, it would be accelerated in two different directions equally. My guess would be to include an AC/DC converter to charge up a massive capacitor bank for use in the railgun. But then, would it ionize? Probably not, if you're correct - unless ionization in this case has less to do with voltage and more to do with energy provided. This has me wondering how a plasma railgun even works at all!

And I'm guessing the AC voltage source is an outlet, judging from this and your earlier comments on using 240 VAC. Personally, I'd rather avoid outlets, and instead use a battery or some such (probably leading to significantly less ability), but whatever. I've seen boost converters in those disposable cameras manage to ionize krypton for the flash at 350 V (DC?) while being powered by a single AA, so ionizing the gas with a battery is most likely not the problem. From earlier experiments and questions, I've learned that the magnetic force a railgun exerts is limited by the current through the rails. Not knowing anything about the relationships of voltage and current for AC circuits, if the voltage were increased wouldn't the current fall proportionally?

It can be found by examining whether the electric cell in question is a galvanic cell or electrolytic cell, for starters.

Ah. Unfortunate. Oh well, it was rather impractical. Again, what circuit and power source do you use? I've seen a couple different variations.

So, to change the wavelength of the emitted photons, I would (might) have to change the electrodes? Sounds doable, thanks. Although, could carbon electrodes even be used for a railgun? What's your circuit for your cascade generator?

Hmm. Does this mean this cannot be utilized outside of a vacuum or inert atmosphere? If so, that's a damper. Is there risk of electrocution? What is the container for those two wires in your pictures? It might be a trick of the light, but the second photo appears as if the wires are encased in a glass spheroid. Also, the wires weirdly remind me of those jumper wires I find in my Arduino kits. John C: Yes. I couldn't get the smaller ones to go across, so I scaled it up a bit. As for the chemical reactions, the two main ones that come to mind are production of NO2 and O3 (as mentioned). While this might result in a bit of a smell, you'd think the speed of the pulse would ensure that not much is produced... right? When I Googled images of "plasma railgun", I came up with this: It's actually a movie, and the picture above only appears for one frame, with a noise like a shotgun. (I wish there was some way to dampen the noise... ah well.) Also, this is such a silly question, but is there any way to change the color of the plasma without resorting to pumping in gases like neon or krypton?

Why do I not see these being attempted more often? A plasma railgun works the same as a regular railgun, except the armature (and projectile) is ionized gas instead of anything physical. Now, the differences I would imagine are thus: -The voltage would have to be very high - typical Jacob's Ladders take about 6 kV from a transformer to ionize air. - Because the projectile isn't solid, it has a lot less friction (and therefore a lot better acceleration and force?) Would the capacitor bank be different? I'm not sure whether plasma would need more or less energy...

For a damnedly slow, but easily done way of making pure sodium hydroxide,place two electrodes (anode carbon, cathode whatever you feel like) in two beakers full of saturated salt water. Soak a paper towel in salt solution, and place both ends into the solutions. Pass current through, and the Cl- ions will migrate to the anode, the Na+ to the cathode, and concentrations of NaOH and HCl/HOCl (or chlorine in water, whatever you prefer to write it as) will slowly increase over time. Back when I had to do this (and didn't just buy it), I used tap water in place of salt water at one end, which would slowly become basic as NaOH was formed at the cathode. Did I mention this is really slow? Not only due to the initial near-lack of conductivity of the tap water I used, because I did use saltwater in both beakers in one try.

Ah well - it was worth a shot... I guess I'll have to stick with neodymium magnets until some better technology comes along, then.

Alright, I feel stupid for posting this, because I have the distinct feeling this will be shot down in a matter of a few posts. But I was discussing a superconducting project with a friend, and also talking about alternative levitation ideas (namely, http://www.youtube.com/watch?v=A1vyB-O5i6E). She asked me why I didn't combine the two, as this would allow me to theoretically levitate anything with a superconducting electromagnet. From my understanding, superconductors have zero electrical resistance when active. So, a superconducting magnet is able to exhibit a current without any applied voltage. The magnetic field used to levitate the frog was 10 Tesla, but I don't have the proper understanding of the math to calculate the appropriate corresponding strength of a superconducting electromagnet. Now, let's say I did build one of these superconducting electromagnets, and it was strong enough to levitate a frog or two. Could it exhibit the Meissner effect and 'lock' the object in two dimensions, or is that specific to magnets only? I'd say it's specific to the magnets, but I would also say frogs can't levitate...

Yes, yes it should. Step 1) Calculate how many moles of reactants and products, using molar masses and stoichiometry. Since molarity is defined as moles per liter, you should be able to work out what to do from here.

^ What on earth happened? Also, what about a non-aqueous medium? Presumably, one would have to find one where thorium compounds were soluble.

I am working on a welding project, and would like to know how to introduce a sharp bend in a piece of relatively thin (1-2mm) sheet steel. Would heating be required? I would like the smallest bending radius possible, but don't have access to fancy equipment.

And I read the post. I was reading off the battery. Anyway, to get it up to the desired voltage (and therefore current), I probably need to build a boost converter.

Says 20 hours on the battery. So, I presume that means that if it were to run at 4.5 A, it would be able to do so for 20 hours.

I recently acquired a sealed lead-acid battery, 6V, 4.5 Ah, 20 h for use in electromagnet experiments. I assumed that this would output 4 amps, given the ratings previously mentioned. However, it only outputs about 0.06 or so. How can I get this up to 4 amps or more? I would like to use this, an F630 MOSFET and about 710 ft. of 32 AWG magnet wire for Arduino-controlled magnetic levitation, but it's a moot point if the current is so low. Is there a way to force it to get higher, even if it does shorten battery life?

Iodine actually does dissolve in water to some extent, turning the liquid yellow. The reason halogens can dissolve in water is because they disassociate into their respective acid and oxy-acid, in chlorine's case HCl and HOCl. This reaction is reversible. Curiously, bromine is very highly soluble in water, whereas chlorine and iodine are not. This may have something to do with bromine being a liquid (and thus being miscible with water where a gas and a solid might not be). However, that's speculation.

And you believed that rubbish? Sure, bacteria from a beaver's butt might make it into your yogurt, but the concentration would be laughably low. You'd be better off worrying about the amount of Toxoplasma gondii in your food.

I've been looking into cheap alternatives for clear casting resin, and came across a simple, kid's recipe for modeling clay that involves equal parts Elmer's Glue-All, cornstarch and flour. What I'm wondering is - does this stuff dry translucent? I would like to either cast a 'brick' or 'shell' (depending on how thin it has to be to be translucent, if that applies) that will diffuse the light from 7-8 LED's to make an even color (the LED's are evenly spaced). In addition, if I do have to cast a three-dimensional shape out of this, would it be possible to coat the sides with petroleum jelly for a 'mold release'? As far as I know, it should work - an often-used trick for glue bottles is to coat the bottle caps with mineral oil or Vaseline so they don't stick.

Talked to my teacher about this. He said to use the following equations: W=Fd F=μkN So, W=μkNd =μk(mgcos(θ))((-mgcos(θ)μs-mgsin(θ))/k) From the above post, it seems like 'd' denotes work - but isn't it displacement, making work a different quantity? Since F=kd (Hooke's Law), couldn't W (being Fd) be kd2? I tried solving for the coefficient of kinetic friction as such, and found (μk=-μs- tan(θ)). This is also wrong.

I found online the equation (μk=f/N) where N, in this case, would be the normal force (mgcos(θ)) and f would be equal but opposite to the coefficient of static friction (because the block has stopped moving, meaning the force on the block in the upwards direction equals the static friction resisting it. However, when I input μs/mgcos(θ), negative or positive, neither answer is accepted. What am I doing wrong here?

Have been working on these for days now, and keep coming to the same answers. The problem: A block of mass m rests on a plane inclined at an angle θ with the horizontal. A spring with force constant k is attached to the block. The coefficient of static friction between the block and plane is μs. The spring is pulled upward along the plane very slowly. (a) What is the extension of the spring the instant the block begins to move. (Use any variable or symbol stated above along with the following as necessary: g.) d=(-mgμscos(θ)-mgsin(θ))/k (b) The block stops moving just as the extension of the contracting spring reaches zero. Express μk (the coefficient of kinetic friction) in terms of μs and θ. ??? Part a is right. Part b, I have no idea where to start. I know I should set "d" equal to 0, but what do I solve for from there? Other problem: The potential energy of a 3.9-kg object constrained to the x axis is given by U = 2x2 − x3 for x ≤ 3.0 m and U = 0 for x ≥ 3.0 m, where U is in joules and x is in meters, and the only force acting on this object is the force associated with this potential-energy function. (a) At what positions is this object in equilibrium? (Enter your answers from smallest to largest.) x1 = 0 m x2 = (4/3) m © Discuss the stability of the equilibrium for the values of x found in Part (a). point x1 is in stable equilibrium point x2 is in unstable equilibrium (d) If the total mechanical energy of the particle is 11 J, what is its speed at x = 4.4 m? Because potential energy is equal to 0 when x is greater than 3 (given above), and mechanical energy normally equals kinetic plus potential energy, mechanical energy in this case equals kinetic energy, given by KE=(mv2)/2. So, I set up the math as follows: 11=3.9v2/2 22=3.9v2 (22/3.9)=v2 v=sqrt(22/3.9)= 2.375 m/s This answer is not accepted, even when negative. Why?

If I had to choose, I would say absorb, although rebound works as well. The point is that the force doesn't reach what's being shielded/cushioned by the substance.

Oven bake is usually epoxy. Air dry, in my experience, is usually real clay.