hermanntrude

I believe seeds can be "scarified" using mechanical means as well as by acids. Use some sandpaper, perhaps?

not you, caleb. the original post is duplicated elsewhere

whoops. You're right. I had better check my numbers, because that suggests I should have a duplicate point with 9 iterations for 5 and 8

i'm not using non-integers at all. Interestingly the regular pattern doesn't arise from the repeated meeting of numbers with the same initial ratio. Someone pointed this out to me by suggesting that 55 and 88 are a good pair because 5 and 8 are in the original fibonnacci sequence and 55 and 88 are simply 11 times each of those numbers. BUT, i realised he was wrong to suggest that, and in fact 5 and 8 takes a lot longer than 55 and 88 (55 and 88 is my best data point with only 9 iterations). 8/5 is equal to 88/55, but, 13/8 (the next two numbers in the original fibonacci sequence) is NOT equal to 143/88. I intend to re-examine my data and pick out those points which are the result of numbers which are multiples of fibonacci numbers, to see if they are always "good" points. I suspect, actually that prime-number multiples of fibonacci numbers might be the best ones, although i'm not really sure why.

please don't post the same thing twice.

I've made a total of 50 or more compounds which had previously never been made before. However, you're right that it's easier your way

thatnks for that tidbit of info, tree... I had found the lucas numbers while reading but not the lucas sequences page. However, no mention is made of the relationship between lucas sequences and the golden ratio.

i suspect that reaction wouldn't go to completion and you'd end up with an unholy mixture of acids and salts

OK so I got my luminol today and I've been reading various demonstration sheets across the interwebz and seen that people use various different combinations of oxidiser and catalyst. So i've read that you can use Fe2+ or Cu2+ or other metal ions to catalyse the reaction, but potassium ferricyanide seems to be a popular choice. My question is this: why bother to use such an elaborate compound when copper sulfate works just as well and costs a fraction of the price? I've got both and i'd like to find out why people choose one over the other in case it'll save me time trying both of them out.

OK so i'm not a big mathemetician but I was reading up on number sequences the other day and of course I found a lot of stuff on fibonacci sequences. I already knew two things: a fibonacci sequence is made by adding the two previous digits to get the third and then repeating any two consecutive numbers in the sequence when divided by each other will produce an approximation to the golden ratio, and the further into the sequence you go the closer the ratio gets to the golden ratio. What I didn't know was this: You can start a fibonacci sequence with any two numbers and it will STILL tend towards the golden ratio. So I wondered whether there was a relationship between which numbers you start with and how quickly it tends towards the golden ratio. So I used excel (badly... i don't know any programming so a more efficient method was out of reach) and plotted a 100 x 100 grid, each square containing a number representing how many numbers were required in the fibonacci sequence starting with the column and row numbers for that square. I stopped the iterations when the ratio reached between 1.6180338 and 1.6180350. I then graphed the plot as a contour plot, with colours representing the lowest numbers to make it clear which numbers make the most efficient golden-ratio-calculating-fibonacci-sequence. Unsurprisingly the best ones were in a straight line representing the pairs of numbers which came closest to representing the golden ratio on their own. However, the line contained certain pairs which were better than others. I intend to draw a larger graph with the help of some programming, but i'm seeing an interesting pattern in the "good" points on the line. Points which take identical numbers of iterations are regularly spaced at first, but then when the numbers get higher, new points are added to the regular spacing. The distance between the regular points divided by the distance between a regular point and a new one is the golden ratio. I'm not sure of the significance of these results or whether this has been investigated before but I thought you guys might want to discuss it. I'll upload better graphs when I get them.

nevertheless, a molecular modelling kit will give you a good approximation to the bond angles as long as you use the right atoms from the kit. the trouble is you have to know VSEPR and Lewis theory to be able to choose the right atoms. For instance, if you have a molecule with one central atom and four identical terminal atoms ([ce]XeF4[/ce] for instance), you'd be looking for a central atom in the box of atoms which had four holes. You'd find at least two types of atom like that. which one would you choose? the one with tetrahedral arrangement of holes or the one with four holes all in a plane? Lewis theory and VSEPR will tell you.

i'm concerned about the black duct tape. It will absorb the heat, you're right, but why do you want it to be absorbed? surely you want it to be NOT absorbed. You want the heat to stay in the water. As was stated previously the most important thing is to prevent covection. Perhaps that can be done by ensuring there's no air inside?

i'm afraid you've got quite a bit to learn before getting to the point where you can predict the bond angles. In the course I teach, covalent bonds and ionic bonds are in chapter 2 and VSEPR (the theory which helps predict bond angles) is in chapter 11. A good chemistry textbook and some friends or people with a bit more knowledge of chemistry to bounce questions off will help if you want to go faster than your school is going. sorry to not answer your question fully but it'd take a good few pages and even then it might not be useful to you.

audaciity, please don't do that.

i'm sorry I can see only one reason, and that is the first law of thermodynamics.

the most easily available acid is probably acetic, but i don't know what the acetate ion might do to your plants. After that, hydrochloric might work, since chloride ions are everywhere anyway....

good luck! I'd love to see the results.

hydrogen peroxide and iodide or manganese dioxide or various enzymes (including catalase, which is in blood) will make oxygen.

Or both samples have 50% of A and 50% of B and there is a 10% error in the experimental method.

the magnets will need to be as strong as you can afford, perhaps stronger.

walsh how many times do we have to tell you not to mix acid and bleach? seriously do you not read our responses or are you just trying to annoy us?

if the fluid will be 1 inch deep, you're going to want VERY strong magnets. It also depends on whether you want the fluid to just form round humps or those spikey creations you see in all the videos. You'll want stronger for spikey.

the comments on the video seem to be saying that it's because the water droplets float on a layer of steam so don't come into contact with the pan. I suspect it's a bit more than that... I suspect that the water not only floats on some steam but because of that it become superheated and does not boil... this can happen when there is no surface for the bubbles to form, and when a droplet is floating on the steam like that, that's exactly the case. I suspect if you used dirty water or put a grain of sand in the water droplet (froma distance!) it'd immediately boil.

Yes it should be fairly safe. The product is flammable, but then so are the starting materials. It's also an irritant and probably not great to drink, but other than that, yes, no problem. However I'm not too sure how easy it's gonna be... isopropyl alcohol is a secondary alcohol and hence it's quite hard for the acid to get at the alcohol group. nevertheless, I expect you'll find a synthesis online somewhere, or perhaps a better organic chemist will pipe up here and let you know more details.

I have a PhD in chemistry. In england, before I left, I did a one-year postdoc and earned £27,000. Postdoc-ing isn't very well paid, but a professor would earn much more. Here in newfoundland, I get CA$58,000, which is worth about £33,000, and actually it's worth a ot more, since you can buy a 3 bedroom house here for CA$100,000 which is the equivalent of £56,000.