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Latest Posts by theperpetualscholar - Page 7
Structural differences between DNA and RNA. DNA, or deoxyribonucleic acid, is like a blueprint of biological guidelines that a living organism must follow to exist and remain functional. RNA, or ribonucleic acid, helps carry out this blueprint’s guidelines. Of the two, RNA is more versatile than DNA, capable of performing numerous, diverse tasks in an organism, but DNA is more stable and holds more complex information for longer periods of time.
What makes fireworks colorful?
It’s all thanks to the luminescence of metals. When certain metals are heated (over a flame or in a hot explosion) their electrons jump up to a higher energy state. When those electrons fall back down, they emit specific frequencies of light - and each chemical has a unique emission spectrum.
You can see that the most prominent bands in the spectra above match the firework colors. The colors often burn brighter with the addition of an electron donor like Chlorine (Cl).
But the metals alone wouldn’t look like much. They need to be excited. Black powder (mostly nitrates like KNO3) provides oxygen for the rapid reduction of charcoal © to create a lot hot expanding gas - the BOOM. That, in turn, provides the energy for luminescence - the AWWWW.
Aluminium has a special role — it emits a bright white light … and makes sparks!
Images: Charles D. Winters, Andrew Lambert Photography / Science Source, iStockphoto, Epic Fireworks, Softyx, Mark Schellhase, Walkerma, Firetwister, Rob Lavinsky, iRocks.com, Søren Wedel Nielsen
Jupiter’s giant red spot is also red hot
New evidence suggests the spot acts like a red-hot stove burner that warms the atmosphere above it. Scientists found the average temperature in the upper atmosphere above the red spot is a sizzling 1,600 degrees Kelvin (about 2,420 degrees Fahrenheit). The research team found evidence that the Great Red Spot generates two types of turbulent energy waves.
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Major types of Engines
Straight In-line
This is the type of engine that you find in your quotidian car. Nothing fancy, just all pistons arranged parallel along the vertical direction.
V in-line
Now, this is the sort of the engine that you find on sports cars like the Ferrari. When you hear sports enthusiasts go ‘ Whoa, that’s a V-12! ‘ - it just means that the engine has a V-type arrangement with 12 cylinders.
V + Inline = V-inline
Commonly referred to as the VR engine.
The name VR6 comes from a combination of V engine (German: V-Motor), and the German word “Reihenmotor” (meaning “inline engine” or “straight engine”)
Volkswagen’s VR6 engines, and the later VR5 variants, are a family of internal combustion engines, characterized by a narrow-angle (10.5° or 15°) V engine configuration.
a: straight engine, b: V engine, c: VR engine
W engine
A W engine is a type of reciprocating engine ( again created by Volkswagen) arranged with its cylinders in a configuration in which the cylinder banks resemble the letter W, in the same way those of a V engine resemble the letter V.
A W16 engine is used on the Bugatti Veyron. That’s 16 cylinders!
Flat Engine
Flat engines offer several advantages for motorcycles, namely: a low centre of gravity, smoothness, suitability for shaft drive, and (if air-cooled) excellent cooling of the cylinders. You can find them on aircrafts as well
Radial Engine (aka the dancing starfish)
They were used mostly in small aircraft for the propeller
The big advantage of radials was their large frontal area, which meant they could be air cooled, meaning less maintenance, failures, and of course a lower cost of initial purchase and maintenance.
Wankel Engine
This engine has only 3 moving parts and can make a lot of power.However, they are pretty inefficient, the last car to use this was a Mazda RX-8.
Axial Engine
The axial engine is a very interesting design. But they are not widely used because they are just hard to make and running these things at high RPM’s is a challenge.
Duke engines are equipped with this type.
Jet engine
Commonly jet engines refer to the engines that are found on, well Jets!
Air is sucked in through the front and squeezed. A controlled explosion follows and the exhaust is blown out through the back
But, Jet engines also include the engines that are found on rockets, hybrids and water-jets. And their mode of operation is different than the one mentioned above.
Pretty cool eh?
Have a great day!
PC: Howstuffworks, Duke, MichaelFrey, Azure.km
** There is also the Stirling Engine. It’s amazing and a topic for an another post. But if you are interested do check out more about it here.
EDIT : Had forgotten about the VR and the W-engines. My bad! Thanks for pointing it out.:D
What is Brightness?
There has always been this nudge,right. The nudge to know what IS brightness. The subtle divergence between what we perceive as dim and bright. What it really means!
The brilliance of the sun whose light emerges afar blinds us but yet the quotidian florescent light seems to oblivious to us. Why this madness ! It doesn’t make sense to me.
Light as a particle
Two light bulbs 100W and 20W respectively. It is obvious that the 100 W glows brighter than its counterpart.
This is so because each photon ( a particle ) carries with it an amount of energy proportional to its frequency; E=hν. The energy dissipated per unit area is the energy per photon times the photons per unit area per second.
The 100 W bulb emits more photons per second than the 20 W bulb.
In this model, the photoreceptors in your eye undergo chemical reactions as a result of absorbing photons. The more photons absorbed per second, the brighter the light appears.
Light as a wave
In the picture of light as an electromagnetic wave, the energy carried by the light is proportional to the square of the wave’s amplitude.
In this model, the photo-receptors in your eye are oscillators. What is oscillating? Electric charge.
Charges are accelerated in response to the electric field of the light: the greater the electric field (or amplitude), the greater the amplitude of the oscillation, and the greater the electric currents in your eye (and the greater the brightness).
The human eye is truly a marvel. The level of serenity it brings to life is just enthralling.Have a great day!
- Post adapted from this stackexchange.
Important Questions
Earth Facts
Read Books
Climate Change
Strange Weather
Since US history is all the rage now, I thought I’d share some of my favorite stories about the founding fathers.
-John Adams and Thomas Jefferson once visited the home of Shakespeare together… and both broke off pieces of one of the writer’s chairs so that they could take home souvenirs.
-When he was given an official surrender document during the French-Indian War, George Washington blindly signed the thing because he didn’t want to admit he couldn’t read French. In doing so, he basically solely accepted the blame of multiple war crimes. Somehow he wormed his way out of this… one of his methods was to blame his translator.
-Ben Franklin was forbidden from writing the Declaration of Independence because the founding fathers thought he would try to slip in puns and jokes.
-John Hancock was a convicted smuggler. Charges were dropped against him after he hired John Adams for a lawyer.
-Aaron Burr was a firm believer in the intellectual equality of men and women and lobbied for women’s suffrage.
-John Adams named his dog Satan.
-James Madison was our smallest president, at 5'4" and roughly 100 pounds.
-When he was 26, Washington bribed voters into electing him into office with alcohol… he gave certain voters about a half gallon for choosing him.
-Ben Franklin once wrote an essay urging scientists to “improve the odor of flatulence.”
-Jefferson warned Lewis & Clark to beware of giant sloths during their expedition.
-Adams and Jefferson were the original bros; after a lifetime of friendship, bitterness, and more friendship, they died hours apart on the same day- July 4th. Adams’ last words were, “Jefferson survives.” Well, not quite.
-Washington crossed enemy lines during the Battle of Germantown to return a lost dog to General Howe.
-The Star Spangled Banner was based off of a rowdy English drinking song.
-Alexander Hamilton’s descendants heavily edited and even hid some of his letters to his totally hetero bro, John Laurens, claiming “the content was embarrassing and indecent.”
-Ben Franklin opted for the turkey to be the U.S. national bird, claiming that bald eagles were cold and volatile.
-A few days before signing the Declaration, the Constitutional Convention got LIT. It’s rumored that the founding fathers drank 54 bottles of Madeira, 7 bottles of Claret, 7 bowls of spiked punch, 22 bottles of porter, 8 bottles of whiskey and 8 bottles of hard cider in this one night.
* Assuming that the whole planet stays intact, and that the whole core of Saturn will not slide down from the gaseous atmosphere. (I do not wish to see the destruction of the whole planet.) Saturn will only float in theory because it is lighter than water. Of course if you literally get Saturn into a tub of water, there would be a lot of issues. They are addressed in his article. But overall, for something so huge and stellar, it can still be less dense than water!
Galileo and the Jovian Satellites
On the nights of January 7/8, 1610, Galileo Galilei noted in his notebooks the discovery of the first 4 Jovian moons, which he named after the powerful Medici family, naming them Medicean I, II and III. The name Europa (above left) comes from Greek mythology-Europa was abducted by Zeus (the Greek name for Jupiter) in the form of a bull and bore him many children. Io is also named for a child of Zeus (Jupiter), the daughter of Inachus, who was raped by Jupiter. Jupiter, in an effort to hide his crime from his wife, Juno, transformed Io into a heifer. Calllisto (on the right) was named for another seduction of Jupiter. Callisto was the daughter of Lycaon, who was a follower of Artemis, famous as goddess of the hunt and for her chastity. To punish Callisto for lying with Jupiter, Artemis banished her. Without protection, Jupiter was forced to change Callisto and her son into bears to hide them from his wife Hera’s fury. Eventually, Jupiter placed them both in the sky as the Ursa Major and Minor, the Big and Little Bears (known today as the Big and Little Dippers). Ganymede was the fourth moon discovered by Galileo, named for the shepherd boy known for his incredible beauty and kidnapped by Jupiter. These names would not become common for several hundred years. Today, Jupiter has fifty named moons:
1. Io 2. Europa
3. Ganymede
4. Callisto
5. Amalthea
6. Himalia
7. Elara
8. Pasiphae
9. Sinope
10. Lysithea
11. Carme
12. Ananke
13. Leda
14. Thebe
15. Adrastea
16. Metis
17. Callirrhoe
18. Themisto
19. Megaclite
20. Taygete
21. Chaldene
22. Harpalyke
23. Kalyke
24. Iocaste
25. Erinome
26. Isonoe
27. Praxidike
28. Autonoe
29. Thyone
30. Hermippe
31. Aitne
32. Eurydome
33. Euanthe
34. Euporie
35. Orthosie
36. Sponde
37. Kale
38. Pasithee
39. Hegemone
40. Mneme
41. Aoede
42. Thelxinoe
43. Arche
44. Kallichore
45. Helike
46. Carpo
47. Eukelade
48. Cyllene
49. Kore
50. Herse
and an additional 16 provisional moons:
1. S/2003 J2
2. S/2003 J3
3. S/2003 J4
4. S/2003 J5
5. S/2003 J9
6. S/2003 J10
7. S/2003 J12
8. S/2003 J15
9. S/2003 J16
10. S/2003 J18
11. S/2003 J19
12. S/2003 J23
13. S/2010 J 1
14. S/2010 J 2
15. S/2011 J1
16. S/2011 J2
All images courtesy NASA. Thanks also to NASA for additional historical background.
We hope tonight* you will stay off tumblr long enough to catch the entirely new Camelopardalids meteor shower, which promises be a good one. Comet dust from 209P/LINEAR, sloughed off 200 years ago in its orbit around the sun is due to enter our atmosphere and provide us a remarkable show. That is provided you find somewhere with clear skies away from sources of light.
Sidereus Nuncius, sometimes called Starry Messenger, is a short work by Galileo Galilei in 1610–or almost 200 years before 209P/LINEAR laid the groundwork for tonight’s show. Above is the verso of Galileo’s drawings of the Pleiades star cluster, which makes an exceptional background for our shooting stars. The edition is available for view online in our Heralds of Science collection, a set of books donated to the Smithsonian Libraries by noted book collector and founder of the Burndy Library, Bern Dibner. Our Dibner Library of the History of Science and Technology is named in his honor.
Make Galileo proud.
(*Just fyi: this was originally posted on May 23, 2014—the “tonight” we were referring to. Hoping this slight edit will help with any confusion and unnecessary time away from tumblr. The International Meteor Organization has a calendar of meteor showers, if you’re interested.)
Total Solar Eclipse: A total solar eclipse occurs when the Moon completely blocks the solar disk. In a total solar eclipse, the narrowest part of the path (where the Sun is completely blocked and the Moon casts its darkest shadow) is called the “zone of totality”.
Annular Solar Eclipse: When the Moon is farther away in its orbit than usual, it appears too small to completely cover the Sun’s disk. During such an event, a bright ring of sunlight shines around the Moon. This type of eclipse is a called an “annular” eclipse.
Partial Solar Eclipse: A partial solar eclipse occurs when Earth moves through the lunar penumbra (the lighter part of the Moon’s shadow) as the Moon moves between Earth and the Sun. The Moon does not block the entire solar disk, as seen from Earth.
Image Credit: http://apod.nasa.gov/apod/ap131108.html
In the left column starting at the top they are Orchard Oriole, Red-winged Blackbird, Eastern Towhee, Northern Cardinal, American Robin and Gray Catbird. And in the right column from the top they are Blue Jay, Carolina Chickadee, Song Sparrow, Field Sparrow, Chipping Sparrow and Seaside Sparrow.
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