Why Figure Skaters Make All Their Moves

Figure Skater
Next time you watch figure skating, observe closely this and similar patterns

Tonight I was watching part of the 20.16 US Figure Skating Championship on NBC (an American television network, for foreign readers of this blog).  Ever wonder why a figure skater can do what s/he does, particularly concerning when the skater crosses his/her arms and thereupon spins at a much faster speed?  Sometimes more elaborate moves can cause similar effects.

Some basic physics principles will do here.  First, I shall discuss friction.  Friction keeps things still when they are juxtaposed against one another.  There is a little bit of friction involved with contact of the skates on icy surfaces, which helps allow for quick motion (as inertia keeps things moving unless a force opposes it, in this case, friction applied to stop the skater).  Ice provides just enough friction for starting and stopping the skater, but otherwise it is smooth.

At the very core of figure skating, however, is angular momentum, or the momentum of rotation.  Momentum, when in a straight line, is simply mass times velocity.  In situations of rotation, however, it is the angular velocity (speed of rotation) times the “moment of inertia.”  Without going into details, the latter quantity takes into account shapes of different objects.  Since momentum, by its very nature, must be conserved, a change in the distribution of mass (and hence the moment of inertia) into a more condensed form will cause an acceleration of the skater when s/he spins!

Finally, Newton’s ever-famous third law (i.e., that of equal and opposite reaction) allows the skater to glide forward (or even leap up!), as the force directs down and back.  The exact backward force determines the exact forward force, depending on the details of each.

Like classical music, classical mechanics can sure be beautiful!

Source:  http://www.livescience.com/6120-physics-figure-skating.html

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Why Owls Can Turn their Heads Toward their Backs

Owls, aside from their folklore-based wisdom, bear one capacity that we humans can only dream of:  viewing what’s behind them without turning around.  Their heads can turn 270° from the frontal position, which is really just 90° in the opposite direction.

However, what really warrants this need is 1) their very large, almost motionless eyes, and 2) the arterial organization toward the brain.

In owls, the vertebrae give ample space in certain arteries, which in humans are confined to small spaces.  Also, the carotid artery, a “confined” artery, happens to be at the central axis of rotation.  And like humans, predatory birds, and animal able to hunt, their vision is binocular and thus with good depth perception.

These details and more, can be seen in the attached YouTube video below, courtesy of the principal source (at the bottom of the page, which you can also visit.  By the way, this observation was not primarily studied by ornithologists, but by medical doctors who specialize in vascular issues.  Their insight is highly appreciated.

 

With the eyeful they receive on a daily basis, no wonder they’re considered so “wise.”

Source:  people.eku.edu/ritchisong/birdbrain2.htm

“Pete Can Dance Silly On Camera” – A Paleozoic Mnemonic

(Disclaimer:  I do not take a solid position whether the earth is old or young, nor is it relevant.  This post is just here to demonstrate the power of associative learning, especially mnemonic devices.  Also, I am not a paleontologist or geologist, so don’t assume any scholarly accuracy on my post!)

You may think I’m nuts, but this mnemonic literally rocks!

It stands for, in backward chronological order, for Permian, Carboniferous, Devonian, Silurian, Ordovician, and Cambrian, the six periods of the Paleozoic era.  Broadly, this is life before the dinosaurs, who ruled the Mesozoic era.  Next (the era we live in now, according to evolutionary theory) is the Cenozoic, which is basically the time of modern life (especially humankind).

With mnemonic and other associative methods of learning, you can retain information better.  For example, with the Silurian (which started 430 MYA, according to an old earth), you could use the number 430 and make a statement like “it’s silly to get up before 4:30 am,” a way of relating the two.

Or, for the Cambrian, starting 570 MYA, you could consider the idea of the 570 area code of Pennsylvania, and Cambria County (which is not in 570 area code; if you were wondering, it’s in 814).  But by associating Pennsylvania, a county therein, and one of the state’s area codes, it may be easier to remember.

Mnemonics, don’t you just love them?

Summarization: A Method of Conquering Tough Material

So, in these last days before the Spring 2016 semester, I have enjoyed the diligent work of summarizing more-or-less technical information to get the main points extracted.  As well as trimming extensive detail, I’ve gone an extra step in trimming jargon.  It is a rewarding task that not only is a good method of sharing information, but of personal learning as well.  Some summarized points may appear in future works (perhaps including blog posts!).  And if I need the original detail, it is a good idea to cite the original source(s) in order to track them.

Often, it may be equally smart to give priority to websites over printed books, since information is always subject to change and while the web can be updated, books require revised editions every few years if they are to remain current.  Books can be useful, but will inevitably show their age.  The web, on the other hand, has given a “fountain of youth” to information.

While I do well in understanding deep information, not everyone does.  No problem though, you can use “lighter” materials and thus derive, of course, an even lighter summary!

This is quite “sum” labor of love here!

Get Right on Target When Googling!

Not too long ago, when I want to investigate a topic, I tend to make the error of being too broad.  Instead of Googling my intended item, I would Google a college course’s lecture notes or similar “all-purpose” resource for a subject.  While they can be doubtless rich in information, it will depend on the scope of content that the leader (often, a college professor) wants to contain on his site, both in breadth and depth.

I’m not denying their substantial information is of good quality.  I’m just recommending a different means of searching the web.

My solution here is simply to be more specific.  For example, say “cephalopods” instead of “invertebrate zoology,” or “sapwood” instead of “plant anatomy,” or “electric potential” instead of “physics.”

And once this rule of thumb is observed, you will probably unleash far more power than by doing a search on a broad topic.  You may even cross paths with those “all-purpose” sites mentioned above, such as course notes.  But since you are aiming for what you want, when you need it, it doesn’t matter what the identity of the sites are.

I wish you some “bull’s eyes!”

College Courses Just Around the Corner!

On January 20, I start my next batch of college courses at the Community College of Philadelphia, namely, Calculus I and a Chemistry course, the latter for preparation for the majors-level Biology and Chemistry in the fall (or even summer!).

Since I will be more focused on coursework (and the textbooks that go with them), I will leave the pleasure text reading aside until after the bachelor’s is complete.  If I don’t cross paths with the subject matter of the sold books (yes, Cedar City!), no problem, I’ve got Amazon (and maybe other sites) on your side in case you still want them.  (Cedar City Books is a seller in the Amazon Marketplace among many others).  Bibliographies at the back pages of books often point the way.  However, many adult duties, such as work, childrearing, etc., may get in the way, so I must always budget my time properly.

In a spirit of lifelong learning, I have a whole lifetime ahead of me to independently learn things not covered in college (if desired) through textbooks and other resources; for now, though, reading and related collegiate activities are paramount.  Indeed, we’ll never get to read all books made.  But rigorous reading not required by the classes (or any hobby for that matter) may become just another Facebook, not in its communicative nature, but in its power to distract.  Again, all things in moderation.

However, I will try to get as much Bible study in there as possible.  But that’s for another post.

Wish me a great spring semester, as my knowledge and understanding blossoms!