Bean bags are awesome.

But I see a few people out there
who are standing,

we've got some over here,

and standing takes more
work than lounging.

Using the Live Strong
Organization's online database

of weight loss resources,

you can calculate

that by the time I'm done
with this speech,

those of you who are standing

will have burned 7.5 more calories

than those of you who are bean-bagging it.

(Laughter)

Okay, here's a question,

speaking of weight loss,
specifically weight,

this speech is live.

I'm actually here in front of you guys,

we're all here together.

But this speech is being recorded

and it will become a video
that people can access all over the world

on computers, mobile devices,

televisions.

I weight about 190 pounds.

How much will the video weigh?

Asking questions like that

is what I do every week
on my channel Vsauce.

For the last two years,

I have been asking really fun questions,

mind-boggling questions,

and approaching them
as sincerely as I can,

celebrating scientific
concepts and scientists.

And I research and write

and produce and host

and edit and upload

and run the social media all by myself,

but it's not lonely,

because Vsauce has
more than 2 million subscribers,

and every month, my videos are seen
by more than 20 million people.

Yeah.

(Applause)

It's very exciting.

I've found that asking a strange question
is a great way to get people in,

not just people, but fans.

And fans are different
than just viewers or an audience,

because fans want to come back.

They subscribe to you on YouTube

and they want to watch
everything you've made

and everything you plan
to make in the future

because we are curious people

and sparking curiosity is great bait.

It's a great way to catch a human.

And once you've caught them,

you have this captive
audience that you can,

with the goal in mind
of answering the question,

accidentally teach a lot of things to.

So, let's take a look
at some of my videos.

Here are eight of them.

But down here in the lower-right corner,

"What Color is a Mirror?"

When people see that,

it's very difficult not to click,
because you think,

"Come on, are you serious?

How could you possibly
answer that question?"

Well, so far, 7.6 million
people have watched

this five-minute video
about what color a mirror is.

And in that episode, I answer the question

and I get a chance to explain
what would normally be kind of dry topics:

optics,

diffuse versus specular reflection,

how light works,
how light works on the retina,

and even the etymology of color terms

like white and black.

Okay, spoiler alert:

mirrors are not clear,

they are not silvery,

like they're often illustrated.

Mirrors, technically speaking,

are just a tiny, tiny, little bit ...

green.

You can demonstrate this
by putting two mirrors next to each other,

facing so they reflect
back and forth forever.

Look down that infinite reflection,
and it will get dimmer,

because some light is lost
or absorbed every time,

but it will also become greener,

because green light,

that is light of a wavelength
that we perceive as green,

is best reflected by most mirrors.

Okay, so, how much does a video weigh?

Well, when you stream
a video onto your computer,

that information is temporarily stored

using electrons.

And the number of electrons on your device
won't actually increase or decrease.

But it takes energy
to store them in one place,

and, thanks to our friend Albert Einstein,

we know that energy and mass are related.

Okay, so here's the thing:

let's say you're watching a YouTube video

at a really nice resolution, 720p.

Assuming a typical bit rate,

we can figure that a minute
of YouTube video

is going to need to involve
about 10 million electrons on your device.

Plugging all those electrons
and the energy it takes to hold them

in the correct place
for you to see the video,

into that formula,

we can figure out
that one minute of YouTube video

increases the mass of your computer

by about 10 to the negative 19th grams.

Written out, it looks like this.

(Whistle)

That's like nothing.

You could call that nothing,
and you wouldn't really get in trouble,

because the best scales
we've ever invented

that we could try to use
to actually to detect that change

are only accurate to 10
to the negative 9th grams.

So, we can't measure it,

but we can, like we just did,
calculate it.

And that's really cool
because when I was a kid,

my school had two shelves
of science books.

That was really cool,

but I read all of them
within, like, two grades,

and it was hard to get more books

because books are heavy,
you need space for them

and moving books around is tougher
than what we can do today.

With numbers that small,

I can fit thousands of books

on my own little personal
electronic reader.

I can stream hours and hours

and days and days of YouTube video

without my computer
ever getting measurably heavier.

And as information becomes that light,

it becomes a lot more democratic,

meaning that more teachers

and presenters and creators
and viewers than ever before

can be involved.

Right now, on YouTube,

there is an explosion
of content like this happening.

The three Vsauce channels
are down there in the corner.

But everyone else,
all together, collectively,

their views dwarf what I can do alone

or with the people that I work with,

and that is really, really exciting.

It turns out that tapping
into people's curiosity

and responsibly answering their questions

is a brilliant way to build
fans and an audience

and get in viewers.

It's even a great way
for brands and companies

to build trust.

So, calculating the weight of a video

is kind of a funny question,

but I cannot wait to see
what we ask and answer next.

As always, thanks for watching.

(Applause)