Quirky Science Facts!

[Racoon]

Not quite. 0°K = -273.15°C. 0°K is the theoretical point where atoms of all elements will stop vibrating.

 

Really? I think you might be right

The book I was reading says -213.16 C in the scientific Notation and Measurements Appendix :confused:

it could be a typo; 1 and 7 would be really easy to slip in printing

 

Would the real Absolute Zero please stand up?

uh, Jay-Qu ? Anyone w/ confirmation?

 

thanks Dagaz...

that is indeed a Quirky science fact :)

 

Keeping everyone on their toes,

Racoon

[Boerseun]

Baluchitherium is the largest land mammal ever known!

 

It lived in Mongolia 20 million years ago, and stood 6 metres at the shoulder, and measured 9 metres from head to tail!

 

It was a giant hornless rhinoceros, and supposedly browsed on tall trees!

 

That's like twice the height of an African Elephant's shoulder!!! :confused:

[Boerseun]

Natural gas does not have any odor. In order to detect a gas leak, some gas companies add a chemical that smells similar like rotten eggs!

 

I knew it! Artificial farts!:confused:

[Racoon]

Baluchitherium is the largest land mammal ever known!

 

It lived in Mongolia 20 million years ago, and stood 6 metres at the shoulder, and measured 9 metres from head to tail!

 

It was a giant hornless rhinoceros, and supposedly browsed on tall trees!

 

That's like twice the height of an African Elephant's shoulder!!! :)

 

Baluchithernium would have made for one helluva' Bar-B-Q! :omg: :confused:

 

Blood letting used to be a common medical practice.

 

Greek and Roman medicine was passed along in the Western world due largely to Islamic scholarship and a few libraries left intact within conquered Islamic territory

[Jay-qu]

yeah rac -273.15C is 0K (not to be confused with ok :confused:) , absolute zero.

[Pyrotex]

Here's a quirky fact.

In Physics, if you want to make ultra-precise measurements of something, you need expensive equipment. A microscope or even an electron microscope. Atomic clocks. Particle accellerators. Etc.

 

If you are making a reflecting telescope mirror by hand, you will need to measure its accuracy (error from a mathematically ideal "parabaloid") to within a quarter of the wavelength of light!!!!!!

 

And yet... measuring such a hand-polished telescope mirror can be done by a reasonably intelligent teenager, using some plywood, nuts and bolts, rubber bands, the lid off a Quaker Oats can, a razor blade and a night light--to accuracies exceeding a ten millionth of an inch!!!!!

[Boerseun]

Hey, Pyro - can we get some details on that? Sounds awesomely cool!

 

A fact on prejudice:

 

A 2006 study by researchers at the University of Minnesota involving a poll of 2,000 households in the United States found atheists to be the most distrusted of minorities, more distrusted than Muslims, recent immigrants, gays and lesbians, and other groups. Many of the respondents associated atheism with immorality, including criminal behavior, extreme materialism, and elitism.

 

It's a sad, sad world...

[Pyrotex]

...A 2006 study by researchers at the University of Minnesota involving a poll of 2,000 households in the United States found atheists to be the most distrusted of minorities...associated with immorality, including criminal behavior, extreme materialism, and elitism....

That is very sad. :confused:

But not very surprising.

We are in fact typically law-abiding and moral.

[ELITISM]The fact that we are also superior in intelligence and wisdom to those religious low-lifes is just something we can't control. :confused: [/ELITISM]

 

Info on mirrors later.

[Racoon]

All poisonous and nonpoisonous land and freshwater snakes are edible. :confused:

 

Even after a snakes head has been cut off, its reflex action can causing it to still bite, injecting poison

[Guest chendoh]

Info on mirrors later.

 

Pyrotex, Boerseun, Have you ever heard of Stellafane? A group of telescope makers in Vermont? They have an informative page on making foulcault and ronchi testers.

A little more advanced, but I have heard and seen of what you say, and the tester does work! :confused:

 

I have a link if you want.

[Pyrotex]

:singer:

{measuring such a hand-polished telescope mirror can be done by a reasonably intelligent teenager, using some plywood, nuts and bolts, rubber bands, the lid off a Quaker Oats can, a razor blade and a night light--to accuracies exceeding a ten millionth of an inch!!!!!}

Hey, Pyro - can we get some details on that? Sounds awesomely cool!...

Measuring the Accuracy of a telescope mirror

 

A reflecting mirror for a Newtonian Telescope, must have a concave curvature that in cross section is a parabola. However, since the focal ratio of such mirrors is F/5 or greater [focal length > 5 * mirror diameter] the difference between the curvature of a sphere and a parabaloid is very small, mere millionths of an inch. Parallel light hitting such a mirror will converge at the Focal Point (FP). The distance from mirror to FP is the Focal Length (FL). The FL divided by the mirror diameter is the curvature expressed as "F/--".

 

The mirror surface is measured at double the Focal Point (2FP). Let's say it is a 6 inch mirror with curvature F/8. The FL is therefore 48 inches (6 * 8), and we make our measurements at the 2FP, 96" from the mirror. Assuming a spherical surface, light that emanates from the 2FP and hits the mirror, will be reflected back to the 2FP.

 

At the 2FP we place the night light and the razor blade very close together. They are mounted on a top-base of plywood and other pieces of whatever. The top-base rides on a smooth dowel rod attached to the bottom-base. The top-base can be slid forward and backward against a rubber band by turning a long 20-pitch screw. Attached to that screw is the lid from a Quaker Oats box; the rim is marked off in 50 divisions. Since a full turn of the lid moves the top-frame 1/20 inch, each division on the lid is 1/1000 inch.

 

In a darkened room, turn on the night light. In front of it is a narrow slit. The image of the slit is reflected and focused to the side of night light, where the razor blade is positioned. By turning another screw, the razor can be made to slowly intercept the beam of light at the 2FP, where the image is.

 

Your eye is on the axis of the mirror just behind the 2FP. What do you see? Since all points on the mirror reflect the slit equally, you see a uniform flat glowing surface. You slowly intercept the light with the razor. Shadows appear on the surface of the mirror. Any defects from a perfect sphere will stand out as if magnified millions of times!!!

 

Now, a parabaloid can be thought of as a sphere with defects. By sliding the top-base forward and backward with your micrometer screw, you can measure the distance between those points where the "shadows" take on certain specific shapes. You take these measurements (to the nearest 1/1000 inch) and plot them on a special chart that can be found in any books on telescope making. This chart relates the size of your mirror, its F-ratio and your measurements to the error between a perfect paraboloid mirror and your mirror. These error bars are typically scaled to the nearest 1/32 of the wavelength of green light, or about a hundred millionth of an inch.

 

:singer: :secret: :singer: :singer: :cup: :singer:

[InfiniteNow]

I am hearing the sound of two hands clapping, resulting from these posts Pyro. Inflate that ego of yours... you deserve it! :secret:

[Pyrotex]

Pyrotex, Boerseun, Have you ever heard of Stellafane? A group of telescope makers in Vermont? ...I have a link if you want.

Sure do! Sky and Telescope magazine, which I subscribed to during my teenaged years, had an article on them nearly every month. Those folks were the "professional" amateur astronomers. Yes, post the link. :secret:

[Guest chendoh]

Sure do! Sky and Telescope magazine, which I subscribed to during my teenaged years, had an article on them nearly every month. Those folks were the "professional" amateur astronomers. Yes, post the link. :secret:

I agree, this will take you to the ATM page (amateur telescope makers) from there you can visit the rest of the site.

http://www.stellafane.com/atm/atm_main.htm

 

:cup:

[Guest chendoh]

Someone, let me know if the link is ok, I checked and it seemed to be.

I'll be over at one more bug explaining.:secret:

[Turtle]

Convex polygons of more than 6 sides cannot tesselate a plane.:secret:

[Qfwfq]

All poisonous and nonpoisonous land and freshwater snakes are edible. :tongue:

 

Even after a snakes head has been cut off, its reflex action can causing it to still bite, injecting poison

A guy I know, from Guinea Bissau, says that the snake meat commonly eaten there continues to writhe a bit, even after being cooked. :xx: