big314mp

Interesting...thanks!

You could also look into an oxygen concentrator, that pulls O2 from the air. A used one may not be too expensive.

You've got a lot of question 1. I don't know enough to do the math on this one. Realistically, you would just add liquid N2 until it freezes. I have no idea how much that would be though...perhaps someone else would have a rough idea? 2. Well, you can just let it thaw slightly, to melt the layer in contact with the metal. Then you have a thin layer of oil between your metal case and the frozen crude. 3. Any plastic sheeting that will provide a good seal (i.e. glue it in place, don't nail/staple it). 4. Not really...get yourself some oven mitts, as the tray will be really cold when you try and take it out. 5. The boiling point of N2 is -196C, so that would be the temperature of the liquid. Just like boiling water is 100C, boiling N2 is -196C. 6. The crude can be sealed, if you so desire. The plastic may crack due to the temperature difference. You may be better off leaving the top off. 7. The liquid N2 will vaporize to form gas N2, which will bubble out. I would think that the liquid N2 would be less dense than the crude oil, and so would sit on top (i.e. it wouldn't mix in with the crude at all), but that's just a speculation. The best I could find on the crude/liquid N2 density stuff was that liquid N2 has a density of .707 g/ml, while crude is somewhere between .790 and .973g/ml http://en.wikipedia.org/wiki/Liquid_nitrogen http://www.engineeringtoolbox.com/liquids-densities-d_743.html

1 amp is 1 coulomb per second. There are 96485 coulombs in a mole of electrons. The chromium in dichromate is hexavalent (i.e. +6 charge). The molar mass of chromium is 52.00 g/mol. Hopefully that is enough info, without completely giving it away

1. Not unless you set it on fire. It won't spontaneously ignite, although it will probably give off vapors that can easily ignite. Solution? Do the experiment in a well ventilated area away from all (potential for) fire and sparks. 2. Nitrogen gas is pretty inert, so the crude won't react with it. On the contrary, the N2 will displace O2, making it virtually impossible to start a fire. With that comes the danger of it displacing the O2 you breathe. Again, a well ventilated area and you'll be fine. 3. The N2 will boil, but small droplets hitting you won't be an issue, as they have very little "cold" due to their small size. Keeping it closed (and insulated) will help keep the N2 from boiling away though. 4. DO NOT SEAL IT! As the liquid N2 vaporizes, it's volume increases by ~700x (I pulled that number out of thin air, but it's somewhere in that region). Sealing it will make it explode. Think sealed container in a microwave, only larger, and with a bunch of really cold stuff that you wouldn't want to be splashed with. 5. Don't set it on fire . In all seriousness, once you add the liquid N2, you'll have better luck setting a brick on fire. And out of curiosity, what program did you use to make the drawing?

I'm speculating here...but since crude oil is a mix of hydrocarbons, some will freeze in the dry ice, some won't. Looking up a couple of melting points for various alkanes (pentane - some of the octanes) shows that there are quite a few that wouldn't freeze in dry ice. You could freeze it to a slurry, and then try and squeeze out the liquid, leaving behind solid not-quite-so-crude oil. They would all freeze in liquid nitrogen though. Put some sort of plastic liner inside the wood to hold the N2, then make sure the box has a hole punched in the top of it (a drill would work) for pressure to escape. You could even wrap the box in fiberglass insulation to save on the nitrogen use. Then just put in your crude oil container, and pour in some N2. Add more as necessary (b/c it will boil off as the crude oil freezes). Just thought of something...acrylic might crack if you pour liquid N2 on it while it is warm...I don't know how to figure if it will crack or not, but perhaps someone else here does.

Out of curiosity, do the balloons always travel in the same direction? Based on my (very rudimentary) understanding of things, if they hit the jet stream, they will always go the same way, right?

<speculating> You may be able to take certain types of fibrous kitchen waste (corn husks, perhaps?) and grind it up in water to form a slurry. Spread the slurry out onto a screen, squeeze mostly dry, and allow to air dry. It would probably be more like cardboard, than paper... </speculating>

The three in front indicates that there are three particles in the nucleus, as opposed to "normal" helium, which has four. Helium 3 has 2 protons and a neutron. Helium 4 has two protons, and two neutrons. The chemistry of the two is virtually identical, as chemistry deals with electrons (and really only the outer shell of electrons), whereas nuclear physics deals with the nucleus. Under normal conditions, helium has 2 electrons. These two electrons balance the charge of the nucleus, resulting in an overall charge of zero. He 2+ is helium that is missing two electrons (i.e. it is missing ALL of its electrons, so it is just a naked nucleus), and He 2- is helium that has two extra electrons. As you can see, the number out front indicates the overall charge of the helium ion (i.e. If you have removed one electron you would write He 1+, as 2 protons - 1 electron = +1 charge). High temperatures, or strong electrical fields can strip atoms of their electrons. Adding additional electrons to an atom is usually not possible unless the ion that is produced is quite stable (otherwise the added electrons just come right off again). He 2- is not a stable ion, so it is not something that can be produced. He 2+ is relatively straightforward to produce, but it requires some extreme conditions. Under normal conditions, helium is not an ion. To convert He 2+ to He, all you need to do is provide a source of electrons, in conditions that are less extreme than those that produced the He 2+ in the first place. Virtually anything can provide the electrons (as He 2+ will grab electrons very strongly). A metal would probably work best. So you aren't really "breaking it free" of the charge, you are giving it back 2 electrons to balance the charge.

Post back if it works well...I'm quite curious.

idk about patching a connection through a laptop... I would look for something like this: http://microcenter.com/single_product_results.phtml?product_id=0213283 This seems too expensive, and there are probably cheaper ones out there. I'm just to lazy to look for them

It depends on how involved you want to be in the machine. If you just want something that works, and works reliably, then go OEM I would only recommend building if you want the experience of building it, or you want a custom/personalized machine. And in both of those cases, it wouldn't be worth it unless you are building a high end machine. Since you are asking about money, you might be best served by just buying a machine. You can't discount the very significant time investment that you will need to make when you build a machine.

and they can only pass through those holes...slowly (think balloon with tiny pin hole).

It was strong enough to lift even the heaviest of the counselors, who they could then push around almost frictionlessly.

I should have clarified. A beer bottle capacitor is for high voltage (i.e. the static you were referring to) as the dielectric (the insulator) doesn't break down under high voltage. I suggested it for collecting static electricity, rather than powering it from a battery. and don't forget...foil,paper,foil,paper. That second strip of paper has to be there. And some electrical tape to make a case for the outside would be good. Have fun! And post back results!

Well, since this is the homework help thread... Consider what would happen to the cell if there were free mixing of the electrolytes (i.e. you just dumped everything into one beaker). Consider what would happen if there was no connection between the two cells (i.e. you had the anode and its electrolyte in one beaker, and the cathode and its electrolyte in another beaker). Consider what porous means (i.e. when something is porous, it is *blank*) Hopefully those point you in the right direction.

I remember way back in science camp, the counselors made mini hovercraft using two vacuum cleaner motors (with attached blowers), a large plywood circle for a frame, and some type of plastic sheeting for a skirt. The blowers forced were attached to the plywood, and forced air under the board...and from there it works like a hover craft. Except it is tethered by an extension cord.

Capacitors are actually spiral wound, rather than in layers like an onion. It's done to get more area in a smaller package. So to build one, you would have a very long strip of foil-insulator-foil-insulator layering, and then roll the whole thing up. A wire attached to one foil strip would be one terminal, and a wire attached to the other foil strip would be the other terminal. If you are familiar with fruit by the foot candy, it is sort of that structure, except doubled (i.e. paper, candy, paper, candy as opposed to just paper, candy). Static tends to be in the kilovolt range, whereas with 4 AA batteries you would only get ~6V of potential. You can take a look at leyden jars and beer bottle capacitors for building a high voltage capacitor, and then hooking it up to an electrostatic generator, such as a Van de Graaf machine, or a Wimshurst machine (if you can find one). If you do this, be very careful as a sizable capacitor/electrostatic machine combo can deal a very nasty punch. I should mention that the foil strips can't touch each other, otherwise the thing would short out internally.

I would go with a good non-apple laptop, as $1500 will buy you quite a bit of hardware. You good game semi decently on a $1500 laptop. A $1500 desktop should be a very competent gaming machine. Or whatever else you prefer. And if you can find yourself a disk, you might want to give XP a go over Vista, depending on your preference. The one problem I see with apple products is that they are expensive but very well built. Being a broke college student, my stuff gets scuffed up/lost quite a bit. It's not so bad to scuff up a cheap(-er, computers are never cheap) laptop, whereas with a mac, you'll feel like you've ruined a piece of art

you can't just take the size of the actual frame, as you have to take into account the amount of math and data used to generate said frame. There is a lot of data that the gfx card has to process to produce even one frame. The primary RAM hog is texture data. Virtually all of the video game textures need to be stored on the card, so data that isn't even being displayed is being stored on the card for fast access. And then you have to throw in effects such as anti aliasing which cause the frame that is rendered to be 2-16 times as large (albeit unoptimized, but AA causes HUGE performance hits in video games). The amount of memory that is used quickly spirals upward. Granted, high end video cards with 512MB+ video RAM rarely run into problems such as this, but the effect can be shown (I'm looking for the video card review that I saw it best in, if I find it, I'll post it). http://enthusiast.hardocp.com/article.html?art=MTQ4OSw5LCxoZW50aHVzaWFzdA== The CoD4 section relates to what I was referring to. http://enthusiast.hardocp.com/article.html?art=MTQ4OSw0LCxoZW50aHVzaWFzdA== The specific page.

To throw in one more point, increasing the video RAM increases the amount of data that the video card can work with. In the most straight forward sense, you can run a higher resolution as there is more space for the increased data. In the real world this can be seen in products such as the 9800GTX vs the 8800GTX. At ultra high resolutions (2560x1600), the 8800 will beat the 9800 because the 8800 has 50% more RAM. In a real sense, frames that large don't fit in the 9800's memory, causing it to have to access system memory, which is painfully slow.

A hydrogen bond is very different from a covalent bond. When you dump urea in water, there is no covalent bond between the water and the urea, just an electrostatic attraction. To the best of my knowledge. urea doesn't really do anything with proteins under normal circumstances. A urea derivative is actually a side product of a peptide formation process used in the lab, so it really wouldn't make much sense to have it damage the product. On the acid side of things, urea really isn't very acidic or basic (although it does break down into the basic ammonia), so it shouldn't really do much to carboxylic acids.

you forgot carrying a beaker of liquid at arms length, with a worried look on your face

http://www.hvchemical.com/chemicals.htm http://www.trinitylabsupply.com/chemicals.htm also ebay. and a million other places online.

You could build one And I'm only half joking...a two dollar thermocouple from radioshack and a resistor. Wrap the two together tightly in something insulating, and calibrate. Could be an interesting little project. Again, assuming you are building a tesla coil: You could make a small coil (few turns) around the primary to act as a transformer of sorts. The voltage on the little coil will be proportional to the field strength around the primary, which is directly related to the amps in the primary.