The " I always wondered" thread

[johncmcleod]

If a human was conceived and grown until full maturity all in space what would he look like when he was done growing?

[Straybow]

Isaac Asimov wrote an essay on longevity. He had the key to comparing various species: normalize lifespan to heart rate. When you do that most species lifespan is around 1 billion heartbeats. Human lifespan is around 4 billion, great apes 2 billion. The real statistical outliers are the parrots, some living 8-10 billion heartbeats.

[Japher]

Good point CyberGnu, I was always think chloride gases. The actual state of the chemical does come into play. Aqeous = definitly stable, NaCl definitly stable - yet Cl- would not exist as a free radical in a crystaline latice... anyway.

Processes to create H2 are tricky since H bonds stringly with almost anything that is easy to take it off of... Fuel cell science is at the leading edge not only of chemisty, but material science, and it will be interesting to see what happens.

How do adhesives work? What makes stuff sticky? What determines how strong a glue is? How does stuff like blutack/rubber cerment work?

Has something to do with viscosity and coehission forces such as surface tension. That is a good question, but I am to drunk to care... Sticky stuff is kewl though.

Oh yeah, on the battery stuff, I heard that there is a battery out there in which one of the solutions contains some kind of magnetic metal suspended in it. When an electrical current is applied through that anode/diode that it draws on the magnetic properties of these metals. Once the anode/diode is completely plated by these particals the battery is essentially dead. Yet, when an electrical current is not present these metal particals begin to fall off of the battery until complete absorbed back into the solution = self recharging batteries... Pretty cool huh?

[GePap]

Actually, all human beings are by default female It takes a set of hormones very early in the womb to transform the basic female form into the male form. I guess the need to get rid of nipples never came up evolutio wise, so why go through the effort?

[Alinestra Covelia]

What happens on the molecular level at the edge of a blade?

[Urban Ranger]

Originally posted by CyberGnu
Urban:


You mean something like
2FeO + CH4 -> 2Fe + CO2 + 2H2?

Thermodynamically unfavourable, unfortunately...

H2 is not a terribly stable molecule, so in order for the reaction to proceed you need to use the H2 in a reaction of some kind.

Well, there are lots of factors you can vary though, say, temperature, presence of catalysts, rate of flow, concentration, etc. You could even try mixtures of things, what happens if CO or water vapour is present, say?

Originally posted by CyberGnu
I don't think it can... The capacitor in an electronic device is based on the Coulomb attraction between the plates, isn't it? There aren;t any capacitors in the battery, so I don't think the electric energy can be stored.

The battery is sort of like a capacitor though.

[Urban Ranger]

Originally posted by johncmcleod
If a human was conceived and grown until full maturity all in space what would he look like when he was done growing?

He would look like a normal person, except without the effects of gravity. So, for example, his muscles are weak, and his bones is like glass.

[Urban Ranger]

Originally posted by Alinestra Covelia
What happens on the molecular level at the edge of a blade?

Not sure what your question is. AFAIK, the material stays the same, just that there's less "stuff" there, so the cross section area decreases.

[Az]

It seems I am outgunned by the PhD student Cybergnu, and the Chemical engineer Japher.

[Urban Ranger]

Don't feel bad

[Willem]

Originally posted by Oerdin
I've seriously wondered why people in the green movement haven't embraced nuclear power. It produces very little pollution and solves, what many of them considered to be, the great threat to the world today, global warming. I don't think GW will be nearly as big an issue as the pundits say but I would like to see fewer fossil fuels used.

The problem is what do you do with all the waste that's left over? Even the plant itself becomes radioactive, and only has a life span of about 50 years. It may produce less pollution while it's running, but the waste products can be just as bad in ecological terms as C02 emissions. And they'll be still be deadly for thousands of years after they've been disposed of. Plus there's a lot of security issues involved with the technology as well.

[Willem]

Originally posted by Kropotkin


There's nother thing I've noticed that I think more than americans have but I still haven't figured out what it's for. In the sink there seems to be some sort of grinder down in the hole. What's the point of that?

It's a garbage shredder. If you rip it up beforehand, it uses less space when it comes to time to haul it away. Or you can get the matter small enough that it just flushes down the drain. Not very many people have those anymore, they were only a fad for short awhile.

[Az]

What happens on the molecular level at the edge of a blade?

What do you mean? do you mean when a blade is used to cut something?

[Willem]

Originally posted by Azazel
actually, a dentist's job is very hard, and AFAIK, they're not MDs, they're are dental doctors, not medical doctors.

I've paid for a root canal, that included a series of around 5 treatements ( in which I had a piece of my gum burned off, and a ceramic tooth carved out to replace my dead tooth) around 100$. The clinic is private and not government subsidized, the job lasted for a total of around 3 hours.

Do you think that dental jobs are expensive here? I want to compare prices.

That's cheap! A root canal alone would probably run about $2-300 dollars, never mind the ceramic implant. I'm guessing here in Canada what you had done would probably cost close to $1000 CAN. At least that's what it cost me when I had a crown put on one of my teeth, which sounds to be about the same thing as what you had done.

[Willem]

Originally posted by CyberGnu
Urban:

Sort of nitpicking: While the O-H bond is somewhat stronger than the C-H bond (about 20 kj stronger), it is significantly easier to break the O-H bond. This is because bond strengths doesn't tell you anything about the intermediates - if you have an ionic process, for example, you get completely different kinetics. Just compare tha acidity of water and methane.

BTW, did I mention that coming up with better ways to break the C-H bond is what I do for a living?

Maybe you can answer my "I always wondered". In the long run, what will be the best way of supplying the hydrogen to our homes and vehicles if fuel cell technology becomes standard? Will the hydrogen be piped after it's been seperated, or will that be done in the home or refilling station by some device?