(clocks ticking) (TV): Meteorologist Craig Beals
here, and today is
October 25th, 1985. And it's shaping up to be
a beautiful day in Hill Valley. Sunny with highs in the 70s,
so perfect day to go to the
flee-market, being held at the courthouse
clock tower, the same
clock tower that was struck by lightning 30 years ago,
at exactly 10:04 p.m. And looking forward to tomorrow
we see another beautiful day... (amp buzzing) (speaker squealing) (explosion) (Jake): I'm Jake,
and how did I get here?
Let's rewind. Whew... I have two loves
in my life: science and movies. So, I decided to put myself
in one of my favourite films,
Back to the Future, to find out
if you could survive it. Could you survive the massive
amount of electricity
from a lightning bolt, time travel paradoxes,
or being blown back
by a giant amp pressure wave? Could you survive
Back to the Future? (explosion) (Back to the Future theme music) - What we just saw is exactly
what happens
in Back to the Future to Marty McFly.
And then, he gets up
and brushes himself off. But what would actually happen
to you in real life if you were
faced with a sound wave? In other words, a giant
pressure wave that had
so much force, it could literally lift you
off the ground and throw you
across a room. Well, to answer the question,
we have an air mortar
filled to 100 psi, and a crash-test-dummy
wired with sensors, to measure head and neck trauma
from impact. The air mortar will recreate
the effect of the giant amp
pressure wave, that Marty experiences,
and the crash-test-dummy
will let us know what injuries Marty
would actually sustain. It wouldn't actually look
like it does in the movie. Instead, it would look
like this... Fire in the hole! (explosion) Let's watch that again
in slow-motion. In the movie, Marty is hit
across his entire body
with the pressure wave. But the result would be the same
if the pressure was targeted
just to the chest. Because the torso has so much
more surface area and weight
than the legs. Either way, it results
in exactly what we're seeing. The legs flipping over the head
as the upper body is driven
into the ground. Experiencing negative 600 Gs. It's negative Gs because
of the incredibly sudden
deceleration. As the head slams
into the ground, the sensors
in the dummy read an impact of 4300 HIC.
Head injury Criterion. An HIC of 2000 is a 90% chance
of life-threatening injury, and our dummy experienced
more than twice that. Marty isn't going to be walking
away from this. Oh! One other fun fact:
Using a slow-motion
FLIR thermal camera, we can see what would happen
to your skin when it makes
contact with the ground, right here. The ground and the dummy's head
suddenly glow bright white from the friction of scraping
across each other. So, to add insult to injury,
Marty would have multiple layers
of his skull scraped away, before finally stopping. So, clearly, this would be
devastating. And if for some miracle
you were able to survive it, you would still have to deal
with... ... the part of your body
that is most sensitive
to air pressure changes. Your eardrums.
But what would happen
if your ear was subjected to as much pressure as that amp
can generate? Well... That immense amount of pressure
would instantaneously rupture
your eardrum, like this... Ew... So, a massive pressure wave
would do permanent damage
to your ear, and it's not just rupturing
one eardrum, it's rupturing both
of your eardrums, which means that Marty McFly
would've never heard the call
from Doc, assuming he'd even survive
the massive pressure wave impact
in the first place. (car tires squealing) - Jake! Look what I made! - Doc! You made a... DeLorean. - No, Jake, this is
a time machine. - It looks an awful lot
like a DeLorean. It does look pretty
sophisticated in here. How does it work? - First, you turn on
the time circuits. This tells you where
you're going, this tells you
where you are, and this tells you
where you were.
Punch in any date you want. You wanna see when
the Declaration of Independence
was signed? Just put in the date.
Wanna go into the future, and see when PewDiePie
past 1 billion subscribers
on YouTube? - I don't know what any
of those words mean. - Oh, right...
It hasn't happened yet. Ah... November 5th, 1955. - What happened on that date? - I had just taken my last
calculus final at MIT. And I tripped on my
pocket protector when it fell
out of my pocket, and I fell and hit my head,
and I came up with the idea
for the flux capacitor. This is what makes
time travel possible. All you need is a little
plutonium. - Oh. Could I take it
for a test drive? Alright. Any important
information I should know before I take this around
the block? - Nope. Can't think of anything. (car starting)
- Alright. Back this up, here... (engine roaring) - Let's see how fast
this thing can go. (tires screeching) Oh boy! - Great Scott! Don't go over 88 miles an hour! (explosion) - What happened? Where are we? (slow rock music) Oh, no... It's 1955. Okay. Uh, let's go back, huh?
Let's just do that,
nothing happened, it's okay. Time circuit's on... No! Argh! There's no more
plutonium. Okay! So... First rule of time travel
is don't interact with anyone
in a way that could potentially influence or change the future. So, we gotta go find Doc
and figure out how we get
back... to the future. - Hey, man! That's a sharp
looking set of threads
you're sporting, brother! And... what kind of car is this?
- Oh, this old thing? Well this is a 1981 DeLorean
that my friend and kooky
inventor, Doc, turned into a time-machine,
and then I accidentally drove it
back to 1955, and now I'm stuck here
because the power source
is plutonium, and I don't have that. - Hmm... Sounds like
an interesting idea
for a moving picture, man. You know, I think I'm gonna
call my cousin, Bob. Bob Zemeckis, and tell him
about this, 'cause we can make
a moving picture about
the future, the car... - Okay, that was my bad.
You know what, let's just
go over the basic principles, the basic rules of time travel,
and also maybe find someone
who knows where Doc is. (car horn honking) (squeaking) Hello. Does anyone know
where Doc lives? - Of course.
1640, Riverside Drive. - Yes! Thank you. Thank you. Okay, so... Back to the basics
of time travel. Let's imagine time
as we normally think of it: as a straight line. But there are a few other ways
to think about time,
and travelling through it. The first is that you have three
timelines: past, present,
and future. If you were able to travel
through time, that means the past
and future exists concurrently
with the present. All of time is happening
at the same time. So when you travel
from the present to the past, you are leaving your timeline
and going to another one. The same if you were to jump to the future. The second theory involves
a wormhole,
or Einstein-Rosen bridge. The basic idea being that
a wormhole could act
as a shortcut, connecting two different points
in space-time. Even though wormholes have not
been proven to exist, this concept fits within
Einstein's general theory
of relativity, whereas the other two
do not. And quick side note:
In regards to relativity, we can actually travel through
time... kind of. If an astronaut on the
International Space Station
had an atomic clock with them, they'd notice that when coming
back home, their clock would've ticked off
less time than those on Earth. Because time is relative. The elapsed time between events
depends on the motion
of the observer. And you can actually experience
this right now. When you look into a mirror,
the light needs to reflect
off you, onto the surface of the mirror,
then off the mirror,
into your eyes, which your brain then needs
to process into an image. So when you do look
in the mirror, what you are
seeing looking back at you is you from the very, very
near past. But back to our straight line.
If we go from this point
in time, and jump to another point
in time, we have created
a loop. We left in 1985 and traveled
back in time to 1955. That moment in 1985
has now become a fixed point, meaning when I'm born
in 1968, I will continue forward
until 1985, when I will then
go back in time. And this will loop forever.
There will always be a version
of me who gets to 1985, and travels back to 1955.
It's a causal loop, where every event
causes another event, that leads to the first event
happening. So, when we...
If we get back to our present, we will no longer be in a loop,
but a version of us that is
slightly in the past will be. And then they'll get out,
and another version will be,
and so on, and so forth. Now, is time travel
as we normally think of it
physically possible? Well, not in real life, because it is not compatible
with the laws of physics, as far as we know.
But, we are in movie physics,
so we need to find Doc and get back to our own time. (joyful music) (knocking) Doc!
- Do I know you? - It's me, Jake,
from the future! - I don't know anyone
from the future, and I definitely don't know
anyone named Jake. - Doc, you gotta believe me!
Today's the day when after
your calculus exam, you slipped on your pocket
protector and hit your head, and that's how you thought
of the flux capacitor! - What are you doing?
You're breaking the basic laws
of time travel! Although, in this case,
the ripple in the timeline
should be minimal. Have you told anyone else
about this?
- No... - Good! Because that would be
a bootstrap paradox. - The what, now?
- The bootstrap paradox! So, the bootstrap paradox is when an object,
or information, or a person gets sent back in time,
but that confuses the origin
of the object. For example, when Marty McFly
goes back in time, and he plays the song
Johnny B. Goode by Chuck Berry, and then Chuck Berry hears
the song, and he's like, "I like that song, I'm gonna
make it mine." And he plays it
on the radio. If Marty had never gone
back into the past, would the song have ever
been created?
That's the bootstrap paradox. - Cool! So, here's the deal.
I accidentally travelled back
to 1955 in your time machine, and I don't have anything
to power it to get back
to 1985, so do you have any idea
about how to get 1.21 gigawatts
to get me back home? - Of course! 1.21 gigawatts,
that would be enough power. Although, the only thing
powerful enough in 1955
to create that much power would be a lightning bolt.
- Great! There's actually going to be
a lightning strike at the clock
tower at 10:04 p.m. - What did I say about
talking about the future?! (thunder booming) (eerie music) - Huh. Everything we need
is already set up. - Whoa, whoa, hey...
What are you doing? - I was gonna ask you
the same thing. - Ah... I'm just working
on some amateur weather
experiment. - Yes! That's right!
Because you become
a meteorologist. He's the...
- I like that. Meteorologist. Craig Beals. - Ugh... Why do I keep
messing with the future?! - Jake! We're running
out of time! (thunder booming, car starting) - Alright, Doc, I think
we're all set.
Time circuits are... on! Put my date in, and I guess
I'll see you in a little bit. - I'll see you in 30 years! - You know... Gotta say... This all worked out
pretty great.
(lightning striking) - Great Scott!
- Doc! What do we do?! (Craig): Don't worry.
I got this, guys. - Oh, it's Craig. - I'll just... grab the two ends
and hold them together, Like Doc Brown did
in Back to the Future. - Craig, I would not do that,
that is an extremely bad idea. - Why? Because I'm holding
an uninsulated cable, and I don't have insulated
gloves? So the electricity's
gonna flow through this wire and into my body,
and down into the ground, because electricity's always
looking for the path
of least resistance to get into the Earth,
which means I'll likely
be electrocuted, and very little, if any,
of the electricity will actually
make it over to the car? - Yeah, that's... actually
exactly right.
(thunder booming) (electricity crackling) - Uh... Do you think Craig's
okay? (Jake): I mean, that much
electricity coursing through
somebody's body is definitely not good. But to find out exactly how bad
it would be, we happen to have
a machine to test just that. (thunder clap) It takes an electrical current
of 100 to 200 milliamps
to be lethal. That's just 0.1 to 0.2 amps. And this six metre tall
Tesla coil generates
an electrical current of 30,000, which happens to be
the average amperage
of a lightning strike. And, yes, people have been
struck by lightning before,
and survived, but that's generally because
it's a branch of the lightning, which travels either through
the ground into them, or strikes them from tens
of metres above. But what Doc brown experienced
was a full-on lightning strike, travelling down that cable,
into his body. But what would have happened
to his body? Well, to demonstrate, we have
a discarded piece of pork to
see what happens to your skin. A ballistics dummy to see
what happens to your insides. And me. Except I'm not actually
part of this demonstration, because electricity
is incredibly dangerous.
I can't stress that enough. Please do not play
with electricity. Which is why we're going to be
standing over... ...here. Over ten metres away.
Let's do it. (electricity crackling) (eerie opera music) (Jake): Let's watch that again. Once the lightning reaches
the wire touching our Doc Brown
stand-in's hand, that wire turns into
the fourth state of matter:
Plasma. Because that bolt of lightning
is extremely hot. As much as five times hotter
than the surface of the sun. Meaning that your hands holding that wire
would be burned to the point of not being
recognizable. And once the electricity
comes into your body, and goes through your arms,
it enters your chest. Your blood vessels would burst
due to the heat and electrical
discharge, your heart would stop,
and your internal organs
would burn. Also, if this dummy
was wearing clothes,
like Doc was in the movie, the fabric would've immediately
ignited, engulfing your body
in flames. Oh! And if the electrical
current had entered your skull,
it would cook your brain. Cool. So, since Doc Brown
was holding onto the cables as the electricity passed
through, he would be horribly
injured, if not completely dead.
Leaving Marty trapped
in the past, just like I am now. However... Is there another
bolt of lightning? (thunder booming,
lightning crackling) - Jake, hurry! You know, to time a lightning
strike with the connection
of a wire would be nearly impossible,
because the speed of electricity
through a wire is almost the speed of light. Anyway... back to the action. (electricity buzzing) (engine revving) (explosion, triumphant music) It worked! We did it!
See you in the future, Jake! (Craig): Can I get some help,
here? (explosion) (triumphant music) (sighing) - I'm back. Ten minutes before
I previously left, which should be enough time
to hide the DeLorean, so Doc and my other self
don't see it, avoiding
a potential paradox, and enough time to stop
my previous self from travelling
back to 1955, so a version of us isn't trapped
in a causal loop forever. Yeah... So... I need to let myself know
without causing another paradox. I need to find something
to write with. Oh! And as always,
thanks for watching! (eerie music, clocks ticking) (TV): Meteorologist Craig Beals
here, and today
is October 25, 1985. And it's shaping up to be
a beautiful day in Hill Valley.
Sunny with highs in the 70s, the perfect day to go
to the flee-market being held
at the courthouse clock tower, the same clock tower that was
struck by lightning 30 years
ago, at exactly 10:04 p.m.
(eerie music) (explosion) V Sauce! I'm Jake, still, and I hope you enjoyed
this Back to the Future-y
episode of CYSTM, or Could You Survive the Movies? It was a lot of fun to make.
And if you wanna see
how we made it, there is a behind the scenes
video chronicling that. And also,
Craig and Diana made some
awesome new science videos that I cannot recommend
highly enough that
are in a playlist with a bunch of other
YouTube original
learning videos. It's really fantastic. So, if you wanna watch the BTS,
click right over here. And if you wanna watch this
learning playlist with Craig
and Diana, click right here. And as always,
thanks for watching!
(Back to the Future theme music)
For some reason, I thought it'd be one long movie. Not a bunch of episodes.
The episode is pretty good.
It's free! And that's a great price!
I like the fact Jake's taken an approach similar to that of many modern television shows. Release everything at once for a price, but also release an episode a week for free.
I wonder how much this video cost to produce. Seems like a lot