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Posted
I have to do an ecryption program in SCHEME. It's due wednesday. I have no idea what to do. lol

Programming is a science too!

 

I know JAVA, C#, C and C++ and to a certain extent Assembly, but I never heard anything about SCHEME so I can't help you much.

 

I'd say, to a non-professional work, a few random mathematical equations you can come up with are enough to mask the data, but it depends on what specifically is asked in that work.

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Posted
They don't teach creationism, they teach Intelligent Design (which is creationism in a cheap tuxedo).

 

It's not science at all.

 

And you get it easy, over here in Portugal they call it by it's name. We study creationism! ... I did, in high school, like... 2 years ago or so.

Posted
I know JAVA, C#, C and C++ and to a certain extent Assembly, but I never heard anything about SCHEME so I can't help you much.

 

I'd say, to a non-professional work, a few random mathematical equations you can come up with are enough to mask the data, but it depends on what specifically is asked in that work.

 

SCHEME comes from LISP, both are usually unused and unknown, but very good for learning.

But it's very specific, so you really can't help. Thanks anywyay :)

Posted
SCHEME comes from LISP, both are usually unused and unknown, but very good for learning.

But it's very specific, so you really can't help. Thanks anywyay :)

 

:sad:

 

the cake is a lie and this message was too short

Posted

Only if the life of the cat depends on something very simple, like a decaying nucleus, which is able to exist in quantum superposition.

 

Anyway, the guy in that video is a bit irritatingly patronising. :wink:

Posted

I hope this thread hasn't taken over the beloved "homework thread". Chuck if you need any help with physics I'd be happy to, hopefully later in the year I'll be teaching a A-level class, but until then I could do with answering questions that aren't about KS3 biology.

 

PS when did supergrunch get bestowed the blue name thingy?

Posted

 

That was awesome! I wish they used this in my days!

 

Someone care to explain why does the observer effects the electrons? Or is it still unknown?

Posted
I hope this thread hasn't taken over the beloved "homework thread". Chuck if you need any help with physics I'd be happy to, hopefully later in the year I'll be teaching a A-level class, but until then I could do with answering questions that aren't about KS3 biology.

 

PS when did supergrunch get bestowed the blue name thingy?

Hmm, a couple of months ago.

 

And no, this hasn't taken over the homework thread, it is for science appreciation. :wink: If anyone has biology/chemistry/maths questions, post them in the homework thread and I'll try to help.

 

Someone care to explain why does the observer effects the electrons? Or is it still unknown?

It just does, quantum is crazy like that.

Posted
Someone care to explain why does the observer effects the electrons? Or is it still unknown?

 

I think there was something about that in a recent issue of New Scientist - I shall look into it and get back to you.

Posted
Fucking kidneys..

 

Yes, a -very- valuable organ as without them we wouldn't piss, excrete drugs, maintain our acid/bade balance, rid ourselves of waste, etc.. but they ruin my fucking weekends!

 

Had to learn the anatomy, histology and the physiology of how they make piss; how and which hormones effect them; the pathology of a few nephropathies and renal failure. And add to that: the pharmacology of diuretics and testing methods = I've had no weekend and I'm tired. Boo.

 

And wow, first post on about two weeks.. go me!

 

I'm on kidneys atm.

Disecting one next week.

Posted
That was awesome! I wish they used this in my days!

 

Someone care to explain why does the observer effects the electrons? Or is it still unknown?

 

Oh that I can do, The basic basic experiment Young's slits, except passing photons through, you pass electrons. If you choose the right size slits you'll observe an interference pattern very similar to that of light (except with a wavelength corresponding to that on a electron of whatever energy you give it). If you slow the rate the beam of electrons is emitted so that only one electron is passing through the slits at a time, eventually you'll still get an interference pattern. This is because in quantum mechanics the resultant intensity is equal to the probability of all routes to that point. The electron therefore will pass through both slits (as its described as a quantum wavefunction and both slits are equally likely a path) and interfere with itself.

 

The point where the observer interferes is when the observer puts equipment on one of the slits so that they can determine which slit the electron passed through. By taking a measurement you force the electron to pass through one or the other slit, rather than both. You will no longer measure an interference pattern because you know the path the electron has taken, so it can't go through both and interfere with itself.

 

Other examples include measuring individual atoms. Heisenberg uncertainty principle is an example. to measure the position of a electron you have to hit it with an photon, which will affect its position and momentum. I studied bose-einstien condensates for a while, which involve ultra low (nanokelvin) temperature atoms. If you took "photographs" of them in a traditional sense by bombarding them with photons, you'd heat them and completely ruin the experiment.

 

The simple fact is when you observe something you have to interact with it in some way, and that will affect the outcome. This is even more prevalent in quantum mechanics where taking a measurement forces the particle into one quantum state, rather than a superposition, which can completly disrupt the results of the experiment.

 

NB If this doesnt make much sense, I'm a tad tipsy, feel free to PM me if you want anything clearing up/more examples.

Posted

So ultimately, it's as I said - it just so happens that observing something cause the quantum wavefunction to collapse.

 

Am I right in saying that light travels at around walking speed through Einstein-Bose condensates? If so, that's slightly crazy - you could do all sorts of things if you could control light more easily...

Posted

light travels at the same speed as it usually does, very close to c (as BEC's have to made in a high vacuum). The special thing about them is that the wavefunctions of individual atoms overlap to such a degree that they become indistinguishable. Basically what you get is 10^6 or 10^7 atoms acting like a single wavefunction, one giant particle. Its really weird because you can split this blob and then get it to interfere with itself. Seeing patterns of interference with a few million rubidium nuclei is a little strange.

These guys do alot of research and were the first to produce a BEC in a lab. http://cua.mit.edu/ketterle_group/ (the picture gallery has lots of nice images and Wolfgang Ketterle has written a few really nice introductory papers on the subject)

Posted
The eye is so much more fun. Careful though, it can squirt.

 

Don't know if i'll get to do that this year. I did a heart a few months back though, that was an interesting disection.

Posted

No you're right. I'm slightly wrong (possibly completely wrong depending on my understanding of those papers)

 

I did a bit of digging around. this is the website of the group that did it with a bunch of publications about it on. Several of those articles are talking about group velocity rather than photon velocity (the whole phase vs group velocity thing again). Even if it is group velocity they are slowing, its dead useful for sending information and computing, but from those articles it seems the actual photons are still moving at a decentish proportion of the speed of light, just the light pulse as a whole is very slow. I think.

 

Have a look through those supergrunch, there's a few actual papers in the bunch, maybe you'll be able to decipher a little more from them than I could. (personally i think they deliberately write most papers just to sound clever. Thank god for articles)

 

Oh and the whole group vs phase velocity, I found a nice little java applet.

Posted

I don't pretend to understand this in depth - I read it in a popular science book somewhere. Anyway, the papers vary in comprehensibility - the abstract of this one makes some sense. You'll be shocked (:wink:) to hear that I switched from physics to evolution a few weeks ago, methinks I'll go into biochemistry or genetics.

Posted
I studied bose-einstien condensates for a while, which involve ultra low (nanokelvin) temperature atoms. If you took "photographs" of them in a traditional sense by bombarding them with photons, you'd heat them and completely ruin the experiment.

 

The simple fact is when you observe something you have to interact with it in some way, and that will affect the outcome. This is even more prevalent in quantum mechanics where taking a measurement forces the particle into one quantum state, rather than a superposition, which can completly disrupt the results of the experiment.

 

Oh, damn it! I knew about that, but I discarded that idea because I though it was too simple for that to be the reason. If I knew that was the reason I would have stealed your thunder.:heh:

 

On an unrelated though scientifical note, the genes that determine the length of a man's reproductive organ can be inherited from his mother. How deep isn't that?

 

And the woman's reproductive organs can also be influenced by her father, I guess.

Posted
Don't know if i'll get to do that this year. I did a heart a few months back though, that was an interesting disection.

 

I did lungs/heart/tongue all in one the other week, was quite interesting.

 

Here's a pic (I think the spoilers appropriate)

dsc00857em4.jpg

 


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