How heavy is air? - Dan Quinn

Koliko je težak vazduh? - Den Kvin (Dan Quinn)

Transcriber: Jessica Ruby Reviewer: Caroline Cristal

Prevodilac: Mile Živković Lektor: Miloš Milosavljević

You may not realize it,

Možda to ne shvatate,

but from the moment you got out of bed today

ali od trenutka kada ste danas napustili krevet

to the point where you sat down to watch this video,

do trenutka kada sednete da pogledate ovaj snimak,

you've essentially been swimming.

zapravo ste plivali.

Why? Because air is a fluid just like water.

Zašto? Zato što je vazduh tečnost, poput vode.

It has waves and eddies.

Ima talase i vrtloge.

It flows.

Teče.

And when you push air out of the way,

I kada gurnete vazduh na stranu,

it rushes around you into a wake.

okružuje vas brazda.

So why don't we notice it most of the time?

Zašto to uglavnom ne primećujemo?

We commonly think of air as empty space.

Obično o vazduhu mislimo kao o praznom prostoru.

But while one cubic centimeter of interstellar space,

Ali dok jedan kubni centimetar međuzvedanog prostora,

the volume in the tip of your pinky finger,

što je zapremina vrha vašeg malog prsta,

contains roughly one atom,

čini otprilike jedan atom,

the same volume of air has about 10 quintillion molecules.

ista zapremina vazduha ima oko 10 kvintiliona molekula.

If that sounds hard to wrap your head around,

Ako vam je teško da to sebi predstavite,

it happens to be about the same

to je otprilike isto

as the number of insects alive on the planet,

kao broj živih insekata na planeti,

all crawling, climbing, and flying over each other

koji gmižu, penju se i lete jedan iznad drugog

in an enormous, tightly packed swarm.

u ogromnom, zgusnutom roju.

When this swarm of molecules runs into things,

Kada ovaj roj molekula naleti na nešto,

it exerts a force, pressing against the boundaries of the fluid,

on vrši silu i pritiska granice tečnosti,

like water pressing against the glass of a bottle.

kao što voda pritiska staklo u flaši.

This is known as air pressure.

Ovo je vazdušni pritisak.

And while air is lighter than water,

Iako je vazduh lakši od vode,

all those molecules still get pretty heavy,

svi ti molekuli su svejedno prilično teški,

with the total air filling a typical school gym,

tako da je vazduh koji ispunjava tipičnu salu za fizičko

weighing about as much as an adult elephant.

težak koliko i odrastao slon.

So when you walk into a gym,

Kako onda kada uđete u salu

how come you're not immediately crushed

ne budete odmah smrvljeni

by the elephant of air in the room?

vazdušnim slonom u sobi?

Well, first of all,

Pre svega,

because most of it is pressing on the floor and the walls,

zato što većina vazduha pritiska pod i zidove,

and the part that is pressing on you

a onaj deo koji pritiska vas

is pushed back by the pressure inside you!

odguraće pritisak unutar vas!

You see, the air, as well as the water and everything else,

Vidite, vazduh, poput vode i svega ostalog

that fills our bodies exerts an amount of pressure

što ispunjava naše telo, vrši količinu pritiska

equal to that of the air outside.

koja je jednaka pritisku spoljašnjeg vazduha.

Of course, this is no accident.

Ovo, naravno, nije slučajnost.

It's precisely what allows us to survive

Upravo to nam omogućava da preživimo

in the normal atmosphere,

u normalnoj atmosferi,

and what makes it more difficult

i otežava nam život

at high altitudes or deep water.

na velikim visinama i u dubokoj vodi.

And we normally don't feel the air pressing on us

Obično ne osećamo kako nas vazduh pritiska

because it's generally uniform.

jer je većinom jednak.

So even though different amounts of air molecules

Iako vas različite količine molekula vazduha

are hitting you at different times,

udaraju u različito vreme,

the swarm is so thick

roj je toliko gust

that all those little differences average out.

da se sve te male razlike izravnaju.

What happens when air pressure isn't uniform?

Šta se dešava kada pritisak vazduha nije jednak?

This means that the molecules are pushing harder

To znači da molekuli u jednom delu

in one region of air than another,

pritiskaju jače nego u drugom,

driving the air flow from the higher pressure region

pomerajući tok vazduha iz područja višeg

to the lower.

u područje nižeg pritiska.

We feel this flow directly as wind,

Ovo strujanje osećamo direktno kao vetar

and the pressure systems

i sistemi pritiska

that meteorologists are always going on about

o kojima meteorolozi stalno pričaju

are responsible for other weather changes,

odgovorni su za ostale vremenske promene,

from the mundane to the catastrophic.

od običnih do katastrofalnih.

But differences in air pressure

Ali razlike u vazdušnom pritisku

do more than just let us complain about the weather;

ne samo da čine da prigovaramo o vremenu,

they're the very reason we're alive.

već su one razlog što smo živi.

We breathe by lowering the pressure in our lungs,

Dišemo tako što smanjujemo pritisak u plućima,

allowing air to rush in.

što dozvoljava da uđe vazduh.

So the next time you take a deep breath,

Sledeći put kada duboko udahnete,

think of the unfathomable number of air molecules

pomislite o neverovatnom broju molekula

you're commanding to move.

kojima zapovedate da se pokrenu.

We look up at the night sky

Gledamo u noćno nebo

to ponder the infinity of space,

razmišljajući o beskonačnosti svemira,

but unless you're watching this video

ali, osim ako gledate ovaj video

from that deep space,

iz tog dubokog svemira,

there are more air molecules

postoji više molekula vazduha

in and around your body

u vašem telu i oko njega

than there are grains of sand in all the world's beaches and deserts,

nego što ima zrnaca peska na svim plažama i pustinjama sveta,

stars in the visible universe,

ili zvezda u vidljivom univerzumu

or both of those numbers combined.

ili obe te cifre zajedno.

The vastness of the universe

Prostranstvo univerzuma

is right in front of you

je tačno ispred vas

and inside you.

i u vama samima.