144 replies to this topic

[Dauth]

Half life of 5.27 years, while a better solution than plutonium with its tens of thousands of years, it will still pollute the land for a long time. I haven't had a look at a Co-60 bomb, and tbh naming the isotope doesn't tell me much, I am not a textbook

It does negative beta decay, which follows the reaction scheme below

Co 60 -> Ni 60 + e- + anti electron neutrino

The Nickel then spits out two relatively high energy gamma rays which would cook life very effectively, the 5 year lifespan means that it's around long enough to kill off life but a generation underground would be fine.

[̀̀̀̀█]

Ok, here's one.... That I have only come up with one explanation for. (realize this is an oddity.)

Get a regular flame lighter, The cheap kind from 7/11
Light it, and look at the very top of the flame.
I see threads, perfectly straight, rising out of the flame, not necessarily the top.
They go down the longer you have the flame in existence, and sometimes disappear.

What causes this?


Also, as a related subject, have two lighters, and an exposed spark (read: lots of light emitted and visible, compared to electric sparks.) Once again the common lighter works wonders. The source flame has not mattered with what is on my desk, and that is a fairly decent sample. (lol pyro) Light one flame, and and while it is lit, spark with the other lighter around/ above it. Cool little trick eh?

So far I have come to this: For the first thing: Impurities in the fluid/ gas aperture cause some atoms to rise exceedingly fast, causing the threads. This is based in nothing, which really pisses me off.

The second trick is caused by the energized atoms of the flame, reacting and losing their energy. I have already worked out the models and what not for this, just let me know if I am generally right with my assumption.

Main issue is the first phenom. (that's supposed to be an abbreviation, but apparently that's a word....)

[Dauth]

The threads you describe, are they a different colour?
If so they may be impurities in the lighter fluid, or even something that's being burnt in the atmosphere.

Otherwise I am lost for ideas.

[striker26]

Why does water hold on to your skin, needing to be wiped off or dripped off? if you put your hand in a tub of water then take it out, most of the water comes off, but some stays on, even if you hold your hand upside down to let gravity take it.
Sorry for the minor question compared to most other questions, just that i have been thinking about it for a while.

[Penguin_Pyromaniac]

striker26, on 21 Apr 2008, 12:27, said:

Why does water hold on to your skin, needing to be wiped off or dripped off? if you put your hand in a tub of water then take it out, most of the water comes off, but some stays on, even if you hold your hand upside down to let gravity take it.
Sorry for the minor question compared to most other questions, just that i have been thinking about it for a while.

I'm not an expert, but I would say that it's intramolecular bonds holding water to your skin cells and hair. Water is strongly attracted to other water molecules, but they are also attracted to non-water molecules because of polar and non-polar ends. That is also why water is attracted to dirt molecules, due to it's non polar (?) ends, and is capable of removing dirt from your hands.
Feel free to correct me.

As for the match question, that's probably just steam or smoke.

[̀̀̀̀█]

No the threads are the same color as the flame, which is why I really hate it. I could still settle for impurities, but the chances are that it is not.

[Dauth]

striker26, on 21 Apr 2008, 21:27, said:

Why does water hold on to your skin, needing to be wiped off or dripped off? if you put your hand in a tub of water then take it out, most of the water comes off, but some stays on, even if you hold your hand upside down to let gravity take it.
Sorry for the minor question compared to most other questions, just that i have been thinking about it for a while.

The surface tension of water is quite high, slowly fill a glass with water and you will see it bubble over the edge above the height of the glass, once past this point the surface is broken and the water above the top will fall away.

Try it with different liquids, like a thin oil, this one will fall away earlier, all the way up to thick treacle which you will be able to pile higher (IIRC)

pyrobob, on 21 Apr 2008, 22:01, said:

No the threads are the same color as the flame, which is why I really hate it. I could still settle for impurities, but the chances are that it is not.

I have different styles of lighters for my gas stove and have been unable to replicate, can you post some pics please?

[Dauth]

Double post and bump, bringing this back in case people have any questions.

[Chyros]

Why not pin it? There aren't any pinned topic in Science yet, so it's not as it'll get too crowded.

Edited by Chyros, 21 May 2008 - 22:33.

[Dr. Strangelove]

Science question:

Doesn't entropy rule out the existence of black holes?

[Dauth]

I'd think the amount of matter 'blown off' at formation and the energy radiated away as something falls into a black hole should conserve entropy in the measurable universe. Inside the singularity no one can know.

However this is interesting and I will have a further look into it.

[Shirou]

Question..

How does superconductivity work... if that's explainable to a human degree...

[̀̀̀̀█]

Might as well take a stab....

This is with no prior research too......

As far as I can tell, the magnets field changes varying with temperature. The extreme cold probably just curls the field more against itself..... I could show you with my hands what I mean, but yea........

basically, instead of the north field wrapping around the north pole of the magnet, it curls the other way and as such can hold objects. Now if you think of the field as a sort of helmet, the curl arond the edges, making the object rebound from it....
Started typing this earlier and a friend picked me up, finished it when I got home.

[Dauth]

It's a rather nice quantum mechanical effect. According to classical physics you would expect at low temperatures the resistance to drop off with temperature. This is not the case, at the critical point of a superconductor the resistance abruptly becomes zero. In a superconducting wire a current can pass unimpeded and without any external voltage applied. With zero resistance circuits become much faster and stop generating heat to a significant degree (impurities in the material mean normal resistance and thus heat).

Hope this explains some of what you want, they are really cool objects.

[̀̀̀̀█]

So was there any truth to my blab?

[Dauth]

The have Zero internal magnetic field, this contributes to the Zero resistance by Maxwells 3rd law IIRC, so to a degree yes.

[Shirou]

Most stuff of what you told I already knew.. I have read upon the true theory of HOW it gains Zero resistance.. but it was all way too complicated for me...

[Talus]

I know a little about this ...

I actualy did a presentation on superconductivity recently ... it's a bloody complex quantum phenomenom.

Basicaly the low temperature cause's electron (within the lattice of the superconductive material) phonon emmission to increace causing the electrons to travel in pairs (cooper pairs). Then it's like a friend pushing people out the way for you at a music concert so you can slip through with no problems.



If i could upload the presentation i would

Theres a lot more to it than this.

[Talus]

I have a question that i could do with some help with. If you get a chance to answer i'd be greatful

Right

Within cosmology there is Dark Matter and Dark Energy.

Dark Matter explains why the galexies within the universe don't just fly far apart, it essentialy adds the missing gravity between them (if it is indeed gravity that holds them together).

Dark Energy is a, currently, unknown force that is responsible for the, supprising, acceleration of the expansion of the universe.

Both of these things are not proven to exsist in practice at the moment.

But:

More gravity within a universe means a decceleration of its expansion. Hense the presance of Dark Matter essentialy should contribute to causing the universe to slow in expansion.

Rather than inventing a new concept such as Dark Energy would it not be easier to just say that there is less Dark Matter?

Or is it that Dark Energy and Dark Matter do concel each other in some ways but they have fundamental differances in the way they work?

Sorry, this questions been a bitch to word

Cheers

Talus

[Dauth]

We have proportions of Dark Matter and Dark Energy (DE and DM from now on) of about 0.25 Critical density and 0.7 Critical Density respectively.

Quote

Both of these things are not proven to exsist in practice at the moment.

You said it yourself, the DM exists to provide gravity.

The numbers that we have are required because the universe is almost flat in spacetime and these values supply that when you crunch them through the equations.

[Talus]

OK, so they are both there simply to make the numbers come out.

Thanks

I've got something else i'd like to ask, if you have time (i like physics ):

In special relativity an object is said to gain mass as it approaches the speed of light.

This is because that as the objects velocity V tends to c it becomes difficult to accomodate the energy increace within purly kinetic energy, therefore, unable to gain kinetic energy the object gains mass energy.

Einstein once said: "the faster you go, the slimmer you get"

Am i missing something with my facts? if not: how can this be so?

[Dauth]

He is referring to length contraction, another feature of special relativity.

[Talus]

Ok, so as you get faster you get heavier (and therefore time slows) and you also get thinner right?

At a guess i'd say you get thinner because the larger dent in spacetime means that you take up less space.

Am I right in saying that?

I know this situation is entirely hypothetical but it's just interesting.

[Dauth]

It gets odd describing stuff like that without a blackboard and a lot of equations. But probably the best explanation you'll get.

[Talus]

Yeah, cheers for the help anyway.

I get horribly lost when these things are explained to me mathmaticaly anyway, i know my physics theory quite well but the maths just throws me atm :(.