Fun Science Factoid Of The Day

[Amelia]

Quote:

The solid fuel motors have a hole right up the middle, and they burn the entire length of this hole, not just at the bottom end.

This is the exact same fuel that hobby rocketeers use and they make it at home!

What I would like to know, is there ever a future possiblity of some type of fuel that would allow space flight without HUGE external rocket boosters?

[Bravus]

It would have to be a fuel that packed even *more* energy into a smaller space, and I think we might already be approaching some of the limits of chemistry and bonding with the fuels we're already using. The other consideration is the exhaust: the shuttle uses oxygen and hydrogen, which means those big plumes of white exhaust are all just water vapor. (The solid boosters are something else, and presumably have some exhaust impact on the environment.)

The really cool future possibility is the 'space elevator'.

[Amelia]

Years ago when the concept first hit the news, I saw an animation of how it would work. It was a cable with a platform that road up and down and took hours of travel. Of course today the looks of the concept have changed greatly. But one blogger posed this question: What musak do you play in an elevator where the trip covers 62,000 miles? ROFL

[Dottie]

Can we go back to the fertility rates? Could the higher fertility rate in the less educated countries make up for the lack of knowledge which would cause there to be a higher infant-mortality rate?

[Bravus]

I'm not sure how those fertility rates are calculated, Dottie, and whether they are at birth or require survival to age 1 or so. If it's birth then yes, there would be some degree of that, but the populations are still growing over all. I don't usually have any agenda in posting these science bites, but one reason I'd remembered that one is that I think anyone who is concerned about over-population on this planet should be concentrating hard on access to education for women, since that's the thing that has been repeatedly shown to reduce birth rates.

[Bravus]

Some spiders' feet are covered with tiny hairs. These hairs give spiders the strength to hold 170 times their body weight before coming unstuck. That would be the same as Spider-Man carrying 170 people from danger while clinging to a building with his fingers and toes.

Scientists hope that they can use the secret of spiders' stickiness to make better sticky notes, gloves for soccer goalies, and even boots for astronauts.

http://news.nationalgeographic.com/kids/2004/07/spiderman.html

[Bravus]

Visible light in the ocean

Visible light penetrates into the ocean, but once past the sea surface, light is rapidly weakened by scattering and absorption. The more particles that are in the water, the more the light is scattered. This means that light travels farther in clear water. Absorption can be caused by phytoplankton which use the light for photosynthesis, particulate matter in the water, dissolved material in the water, or the water molecule itself.

The light energy of some colors is absorbed nearer to the sea surface than the light energy of other colors. The dimming light becomes bluer with depth because the red, yellow, and orange wavelengths have already been absorbed. We typically see the ocean as having a blue-green color because these are the wavelengths that penetrate the deepest and are scattered back to our eye.

The upper 100-200 m of the ocean is called the photic zone (photo = light). Beyond this depth, light does not penetrate, and it is pitch dark. All the production of food by photosynthetic marine plants occurs in this thin surface layer.

Go to this link (where I got the above) to drop virtual M&Ms in the ocean: http://www.punaridge.org/doc/factoids/Default.htm

[Bravus]

Of the 103 naturally occurring chemical elements, only two are liquids at room temperature.

(bonus points to anyone who can name both without looking it up)

[there buster]

mercury and bromine

[Bravus]

dingdingding - 10,000 points to that man

[Bravus]

one metal and one non-metal, incidentally

[Amelia]

is mercury ever a solid?

[bevin]

Quote:

two are liquids at room temperature

and PRESSURE

I haven't found a site that tells me what elements are liquid at room temperature at 0 pressure - it may be the same set

There is this fun diagram in chemistry that looks a bit like this

HiPressure

| Solid..................Liquid

|

|

|................................Gas

+----------------------------------

Lo Pressure/Lo Temp...............Lo Pressure/Hi Temp

and the exact boundary between the three regions depends on the material

For a fun application, see

http://en.wikipedia.org/wiki/Freeze_drying

For an esoteric use, see

http://www.tulane.edu/~sanelson/eens211/mineral_stability.htm

For the original question...

http://chemistry.about.com/od/periodictableelements/a/liquidelements.htm

/Bevin

[Bravus]

Yes, Amelia, mercury 'freezes' at roughly -39 C and becomes solid

[Bravus]

Hmm, bromine might be a gas at room temp and zero pressure - it's pretty volatile as it is

[Bravus]

Ancient nanotech

Quote:

Another nanotechnology has been around for centuries. It is the use of nanoscale impurities to affect the color of glass. Just as today's well-understood gold nanosphere suspensions provide color indicators for a variety of purposes, medieval stained-glass relied on the same size-dependent light scattering properties of metal nanoparticles.

Gold and silver salts were used in medieval times to color glass used in church wndows. For example, silver particles were used to stain glass yellow, while gold particles were used to stain glass red. The aggregation of metal into nanoparticles with surface-plasmon resonances which variously affected their spectral transmissivity is only today's 20-20 hindsight analysis of archaic technology.

http://nanopedia.case.edu/NWPrint.php?page=over.stained.glass

[Bravus]

Dolphins only take short naps, floating just below the surface so they can rise when they need to. Breathing isn't an automatic function for dolphins, so they need to consciously rise to the surface of the water for air.

http://fi.edu/braindrops/archive1.html

[bevin]

Furthermore, only one side or other of the brain sleeps...

http://www.neuropsychiatryreviews.com/dec06/sleep.html

Quote:

Research has shown that bottlenose dolphins, for example, have unilateral sleep and are able to swim while in this state. "Dolphins never have high-amplitude, slow-wave [sleep] simultaneously in both hemispheres," said Dr. Krueger. "That tells you at the very least that sleep is a property of half the brain. You don’t need the whole brain." Clinical observations have also suggested that a patient could be asleep and awake simultaneously, he added. "To a neurologist, this is not so new."

[Bravus]

That'd be handy for humans: we could schedule all our 'left-brainy' type work for the times when that side is awake and vice versa. Would it change our handedness?

[there buster]

Quote:

Furthermore, only one side or other of the brain sleeps...

anyone who works with teenagers knows this is their constant state.

[Amelia]

But what if the side of the brain that is asleep also controls say, your hearing? Or if your left brain is asleep and your right arm goes to sleep too? Hehehehe

[Amelia]

Bravus, does this apply to all oceanic mammals?

[Bravus]

When is -135^o C (-211^o F) considered a 'high temperature'? When you're talking about 'high temperature superconductors'.

When many metals are cooled to extremely low temperatures, close to 'absolute zero' (-273^o C, -459^o F), they become superconductors. That means they conduct electricity with zero resistance. That might not sound all that exciting, but it allows things like levitation.

See the video

It also means that a current that you start in such a material will keep going for ever, because there's not resistance to stop it.

'High temperature' superconductors don't have to be cooled to the extreme temperatures near absolute zero needed for metal superconductivity (it's very hard to get that cold). They are ceramic materials containing copper, and the record 'hottest' temperature at which superconductivity has occurred is -135^o C.

http://en.wikipedia.org/wiki/High-temperature_superconductor

[Bravus]

Questionable factoid: Bullfrogs never sleep

This is a followup to the sleeping (or otherwise) dolphins story. I've heard this about bullfrogs before but never got really good confirmation (or otherwise) on it.

And Amelia, I'm not sure if we've done the research to know whether the deal is the same with the other marine mammals.

[D. Allan]

This is from Wikipedia:

" Whales and dolphins are also different from humans: they always have to be conscious, as they are conscious breathers, so only one half of their brain sleeps at a time.[9] Sleep becomes difficult to define in lower order animals, such as the bullfrog. Its resting state is too similar to its active state to be considered by many to satisfy the criteria for sleep, but brain activity in the resting state is similar to other amphibians that do meet the criteria when they sleep."