Thứ Ba, 26 tháng 9, 2017

Waching daily Sep 26 2017

After I've been outside playing all day, nothing feels quite as a good as a nice warm bath.

Sometimes I might even stay in the tub a little longer than usual, and when I /do/ finally

get out, I notice that my fingers and toes are kind of ... wrinkly, or pruney, almost

like a raisin!

Maybe that's happened to you, too, if you've been swimming for a long time, or even just

doing some fun water experiments in the sink!

Have you ever wondered why that happens?

Well, scientists have wondered that, too!

And they've learned that it has a lot to do with what our skin is made of, and how

water is so slippery.

Skin covers the whole outside of our bodies, and it's pretty special stuff.

Even though it's hard to tell from the outside, skin is actually made up of layers, and each

layer has different parts.

Now, if we could look at the layers of our skin /very/ closely, they would look something

like this.

There's so much in there!

We have something called vessels in our skin, which are the tubes that carry blood in our bodies.

These vessels are /very/ small and thin, but they're really important!

They can open up wide, or they can shrink down and kind of close up a little bit on the inside.

That's what happens when you've been wet for a long time — those tiny vessels shrink down.

And when they shrink down, that big layer of skin they're inside of gets a /little/ thinner.

When /that/ layer gets thinner, it causes the top layer of skin to relax and get a little looser.

And that's what causes the wrinkles!

The top layer of skin is kind of like a piece of cloth.

When it's pulled tight, it's not wrinkled.

But when it relaxes … it gets wrinkly!

So that's /how/ your fingers get wrinkly.

But /why/ do they get wrinkly — why does it help you to have wrinkly fingers and toes?

Scientists don't know for sure, but they've done /lots/ of experiments, and they think

it's to help you hold things better in the slippery water!

During one experiment, a group of scientists asked people to soak their hands in water,

and to let them get all wrinkled and pruny.

Then they asked the people with pruny fingers to try and pick up small, slippery objects underwater.

Then they asked people who didn't have wrinkly fingers to do the same thing.

Well, it turns out that the people who had pruny hands could pick up the objects underwater

/faster/ than the people who /didn't/ have pruny hands!

It's like the wrinkles on our fingers give us a special grip when it's wet.

Have you ever seen pajamas or slippers with bumps on the bottom of the feet?

The bumps are there because they help keep you from slipping on the floor and falling down.

The wrinkles are kind of the same: they make your fingers more bumpy, which helps you hold

onto things without them slipping through your fingers.

So, as weird as pruny fingers and toes might look, they can be pretty useful!

And once you dry off and wait a little bit, the vessels inside your skin open up again,

and your skin goes back to normal — at least until the next time you take a long bath!

Thanks for joining us on SciShow Kids!

We /love/ getting questions here at the Fort!

So if you have any questions about our bodies, or anything at all, grab a grownup to help

you leave a comment down below, or to send us an email at kids@scishow.com!

For more infomation >> Why Do I Get Wrinkly Fingers in the Bath? - Duration: 3:25.

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Test Anxiety: Crash Course Study Skills #8 - Duration: 8:50.

Hi, I'm Thomas Frank, and this is Crash Course Study Skills.

Henry Fonda was a famous actor with a career that spanned 54 years and included starring roles in classic movies like 12 Angry Men and Once Upon a Time in the West.

He was one of the most well-known and successful actors of his time, bringing home an Oscar, two Golden Globes, and even a Grammy before retiring.

So it might surprise you to learn that Fonda had a lifelong struggle with performance anxiety.

In fact, even when he was 75 years old, with over half a century of acting experience under his belt, he would often throw up before beginning stage performances.

But, despite his anxiety and sudden lack of lunch, Fonda would still step out from behind the curtain and give the audience the great performance they expected.

That's because he understood one of the unavoidable facts of life – a fact that the author Steven Pressfield put so well in his book The War of Art:

"Fear doesn't go away.

The warrior and the artist live by the same code of necessity, which dictates that the battle must be fought anew every day."

If you're a student, you might not be performing on a stage or facing down an enemy army,

but your tests and exams are battles all their own, and they often come with the same feelings of anxiety.

These feelings are normal, and you'll never truly banish them.

If you're doing work that's important to you, you'll always feel some amount of anxiety.

And that can actually be a good thing, because anxiety is an indicator that what you're doing IS important.

Otherwise, you'd be apathetic about it.

However, too much test anxiety can hurt you.

Research has shown that high-pressure situations can actually deplete your working memory.

Additionally, stress caused by anxiety produces a hormone called cortisol,

and too much cortisol can hinder the ability of the hippocampus to recall memories.

This means that it is crucial to learn how to manage your test anxiety.

You have to learn how to perform well in the face of it, and make sure it doesn't consume

your thoughts so you can actually solve that geometry proof that's staring you in the face.

Fortunately, there are several techniques and mental exercises you can use to do that.

Roll the intro!

[Theme Music]

Test anxiety is caused by many different factors, but today we're going to focus on the most common ones, which I call the Three Big Fears:

Number one: A fear of repeating past failures

Number two: The fear of the unknown

Number three: The fear of the stakes

Now, in a minute, we're going to dig into each of these fears and work to figure out how you can combat them,

but before we do that, there is one general purpose strategy I want to share with you.

The next time you feel anxious going into a test, take out a piece of paper and spend a couple minutes writing out exactly what's causing you to feel that way.

This has been scientifically proven to reduce test anxiety.

A study done at the University of Chicago found that students who were given 10 minutes to write about their fears and anxieties before a test

improved their scores by an average of nearly one grade point compared to the control group.

This technique works for pretty much the same reason that using a to-do list works:

It allows you to take all those worries out of your head and store them somewhere safe.

You've probably been in a situation before where you're stressed, and a friend tells you, "Hey, just don't worry about it, man!"

Of course, you can't – right?

You can't just let go of the things that are worrying you – after all, your brain thinks they're important.

However, by writing them down, you're unloading those worries into an external system that you trust.

Subconsciously, you know that they're not going anywhere.

And by doing this, you free up mental resources that you can then devote to doing well on the test.

So that brings us to our first big fear: the fear of repeating past failures.

Logically, everyone knows that failure is inevitable every once in awhile.

"To err is human," wrote Alexander Pope, and the realm of calculus finals is no exception.

But we're not always logical.

In fact, human beings have an inherent negativity bias –

a tendency to remember and give more emotional weight to negative events rather than positive ones.

This is a feature of the brain that's pretty useful when it comes to survival –

after all, remembering which mushrooms made you sick or not to try to shake hands with a tiger is pretty important for survival.

But the negativity bias doesn't limit itself to poisonous mushrooms or tigers;

any negative event can create feelings of apprehension and fear when it comes up again.

So even though almost everyone does poorly on tests and exams at least once in awhile,

when it happens to you, you might naturally fear that it'll happen again the next time around.

So how you do you actually beat this negativity bias?

Well, first, realize that you're not defined by your past successes or failures –

despite what that insidious part of your brain might try to tell you.

While the path you're on right now is certainly in part a product of your past choices, it's not a path with a predetermined destination.

At any time, you can choose to do things differently than you did in the past.

If you're ready to do that, you need to start by analyzing your past mistakes and gathering as much information about them as you can.

After all, you can only improve if you know what you were doing wrong before.

Let's go to the Thought Bubble.

Elite chess players understand this concept really well.

While they spend a lot of their practice time playing games and studying the openings and endgames of players at higher ranks,

they also dedicate a ton of time to analyzing their own past games – especially the ones they lost.

By doing so, they can start to correct bad habits and uncover patterns in their playing, which can then be tweaked or improved in the future.

So take a cue from these chess players – as well as from elite performers in pretty much any other discipline, be it opera singers or figure skaters –

and review your past exams to see how you can improve.

Start by getting your hands on a copy of your past exam;

if your teacher doesn't usually hand these out or let you take them home, talk to them after class and ask if you can at least look it over.

And while you're talking with them, also ask for feedback –

especially if your exam contained short-answer or essay questions where there's no concrete answer.

Once you've got a past exam in your hands, review the mistakes you made.

Don't just acknowledge your mistakes; for each incorrect question, make sure you understand why your answer was the wrong one.

If it was a complex problem – like a math equation – identify the exact point where you made a mistake.

Additionally, make sure you know what the right answer was, and why it was right.

Before you move on, cross-reference the question with your notes, as well.

If you're going to be tested on that question again – like in a final exam – highlight that section of your notes so you know it's important.

You can also create quiz questions for later review.

Overall, shoot for mastery over the material so you don't make the same mistake again.

Thanks, Thought Bubble.

The details of those incorrect questions aren't the only things that deserve reflection.

You also need to figure out why you made the mistakes in the first place.

Ask yourself: Was I unprepared?

And if so, why was I unprepared?

Did I simply not put enough time into reviewing?

Did I ignore the study guide?

Or did I use an ineffective study method?

If you feel that you were prepared, then maybe something went wrong during the actual exam.

Maybe you rushed through and made a lot of careless errors.

Or maybe you let time get away from you and didn't actually finish the whole exam.

Or maybe that creepy AI from Ghost in the Shell hacked your brain in the middle of the exam and forced you to spend the whole time licking your paper.

These things happen.

Whatever the reason was, don't let it get you down too much.

Remember that failure is a great teacher – and it's a better one than success.

Since we remember our failures so well, every one of them is a lesson and an opportunity.

But you need to make sure that you use that opportunity by making a plan for how you'll avoid the mistake in the future.

Just saying "I'll do better next time" isn't enough – you need to know exactly how you're gonna do better.

And that's not all you need to know.

In fact, the more you can learn about your exam in all its facets, the more comfortable you're gonna be.

This is the way to overcome the second of our big fears: The Fear of the Unknown.

People naturally fear what they don't understand, and in general, this is a good thing!

It's another one of those pieces of brain programming that's useful for survival, and most other animals share it with us.

When I visited New York City for the first time several years ago,

I noticed that the squirrels there seemed much less afraid of people than the squirrels back home in Iowa

– but that was because these big-city squirrels had a lot of experience dealing with people, and it was mostly positive.

So try to gain as much experience with the upcoming exam as you can.

Now, we talked a lot about how to do this in the last video on preparing for tests,

but the general principle is to try to replicate the test conditions when you're studying.

Do your best to get access to practice tests and study guides, and create quizzes out of your notes to fill in the gaps.

Additionally, spend some time studying in a classroom that looks and feels similar to the one you'll be tested in,

and quiz yourself under the same time constraints that you'll face during the exam.

You want to make the test feel like a familiar old friend when you actually face it.

As Scott Berkun, a professional public speaker, put it:

"By the time I present to an actual audience, it's not really the first time at all."

That's the feeling you're going for.

And that brings us to the last of our big three fears, which is the Fear of the Stakes.

One of the biggest sources of test anxiety is the feeling that this test means everything

– it's gonna define your overall grade, where you'll be able to go to college, and whether or not you'll get to work for Elon Musk some day.

But in reality, you're rarely going to come across a test or situation that you can't recover from in the case that things go wrong.

Trust me – I actually failed a test in college once.

And Nick over there actually failed an entire class – twice.

And, even worse, I was once fired from a job.

In both cases it was totally my fault, but I learned my lessons, I made sure I never made the same mistakes again, and I moved on.

And even if things don't go perfectly for you, you'll be able to do the same thing.

If that's not comforting enough, try reframing the test in your mind.

Think of it as yet another learning opportunity rather than as a judgement.

After all, a test challenges you to recall what you've learned, and as we've already discussed,

active recall strengthens your mastery over the material.

And – at least for me – viewing a test this way makes it seem a lot less scary.

Lastly, keep in your mind that anxiety isn't something you always need to try to deal with on your own.

If you have anxiety that's majorly affecting your life, don't hesitate to ask a professional for help.

Hopefully you found this week's video to be helpful.

Next week, we'll be switching gears and talking about how to write great research papers and essays.

See you then!

Crash Course Study Skills is filmed in the Dr. Cheryl C. Kinney Crash Course Studio in Missoula, MT, and it's made with the help of all of these nice people.

If you'd like to help keep Crash Course free for everyone, forever, you can support this series over at Patreon, a crowdfunding platform that allows you to support the content you love.

Thank you so much for your support.

For more infomation >> Test Anxiety: Crash Course Study Skills #8 - Duration: 8:50.

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The Health Benefits of ... Cannibalism - Duration: 5:19.

This episode of SciShow is supported by Skillshare an online learning community with more than

17,000 classes in design, photo, and more.

[♪♩INTRO]

You'd think eating your own kind would be a bad idea.

I mean, it can be hard enough to survive and reproduce without having to worry about members

of your own species taking you out, too.

But lots of animals are cannibals, from mantises that eat their mates to mice that eat their

babies.

So there must be some kind of benefit to it.

And since, in the immortal words of The Bloodhound Gang, "we ain't nothin' but mammals,"

you'd expect human cannibalism to have its upsides, too — even if the idea is a little

nauseating.

Obviously, there are social and moral factors to consider when it comes to eating people.

But if you strip those away and just focus on the biology, there's some evidence to

suggest that eating human flesh actually has some benefits.

For better or worse, cannibalism is a part of our shared history.

There's archaeological evidence that in some societies, human was a part of the original

Paleo Diet, accounting for as much as 10% of the protein people ate.

And … human flesh might actually have more nutritional value than other kinds of meat.

We have about the same number of calories as other animals our size, so you'd get

the same amount of energy from eating a person as you would from eating a small deer.

But just like Wagyu beef has much more fat and less protein than a ribeye, human flesh

has its own unique profile of proteins, fats, and other nutrients.

The more closely related your meal is to you, the more closely its nutrient profile will

match your needs, which would make human meat the most nutritious choice for other humans.

Studies in all kinds of animals, from beetles to frogs to fish, have found that carnivores

are healthier when they're fed members of either their own, or closely related species.

But there is a major potential downside to eating your own species: disease.

Because when your meal is more closely related to you, it's a lot more likely to carry

diseases you can catch.

Probably the best cautionary tale comes from the Fore people of Papua New Guinea.

Starting around the 1920s, a disease called kuru started to spread among the Fore.

The name comes from the Fore word for "shaking", since tremors are one of the symptoms.

The sick also walked strangely, slurred their speech, and were prone to emotional instability

and bizarre unprovoked laughing fits.

The symptoms would get worse and worse, and eventually become fatal.

At the peak of the kuru outbreak, hundreds were dying every year.

Researchers have since found that kuru is what's known as a prion disease — the

same type as Mad Cow.

Prions are proteins that are folded wrong, which wouldn't necessarily be a problem,

except that they're hard for our bodies to break down.

And when prions come in contact with properly-folded versions of themselves, they make those proteins

fold wrong, too.

Misfolded proteins accumulate in the brain, causing holes to form and destroying neurons

until the person dies.

But prion diseases aren't contagious — that is, unless you eat something with misfolded

proteins in it.

The kuru prions spread because until the 1950s, the Fore practiced mortuary feasting, where

they ate parts of their dead loved ones to honor them and mourn their passing.

Researchers have found that elderly Fore who survived the kuru epidemic had specific genetic

changes that probably made them resistant to prion diseases.

We've found similar changes in genomes from around the globe, which suggests that prion

diseases like kuru—and the cannibalism that spreads them—were common in our evolutionary

history.

But prion diseases aren't the only reasons you'd think eating people would be too risky,

and this is where things get weird...er.

There are plenty of super contagious diseases that can spread just by touching an infected

person — let alone eating them.

But, despite the number of cases of human and animal cannibalism, we've found fewer

examples of it causing disease outbreaks than we'd expect.

And according to a review paper published in The American Naturalist in 2017, there

might be a good reason for that:

Cannibalism could actually protect people from catching dangerous diseases, because

it gets rid of some of the microbes that spread them.

Sure, eating someone else exposes you to more pathogens.

But at the same time, you're also protecting the rest of your community from coming into

contact with the disease.

A lot of microbes can't survive things like cooking or the destructive juices in our guts,

so you destroy them by eating them.

Plus, removing the infected person from the population, both through their death and any

action that gets rid of their body, means there's one less person spreading the disease

around.

So cannibalism might actually slow the spread of some diseases, or even wipe them out.

You'd still have the prions to worry about, but the net effect of reducing other diseases

could make it worth the risk.

So, the more we study cannibalism, the more it seems like eating other people's flesh

might not be too bad for our health—our physical health, anyway.

That said, I wouldn't recommend trying it.

It can still be pretty dangerous, and when it comes to preventing diseases, modern medicine

is a lot more effective than eating people.

Plus, there are plenty of other ways to practice a healthy lifestyle, and it helps to have

a variety of resources for staying in shape, both mentally and physically.

Skillshare is an online learning community with over 1600 classes in health and wellness,

from nutrition to mindfulness and more.

A lot of these classes talk about how exercise and an active lifestyle are key for success

in creative careers.

In this lesson of 7 Simple Habits of Highly Creative People, habit #5 is literally "Exercise,"

and this class about writing productivity emphasizes the importance of taking a break

from the desk to stretch your legs on a walk.

And if you've by some miracle already nailed health and wellness, you still have something

to learn from Skillshare's 17,000-plus classes in design, photo, and more.

Premium Membership gives you unlimited access so you can improve your skills, unlock new

opportunities, and do the work you love.

The first 500 SciShow viewers to use the promo link in the description will support the production

of this channel and get a free 2 month trial of Skillshare.

Thanks for the support and thanks for watching.

[♪♩OUTRO]

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