- [Diana] We'd like to thank audible for supporting PBS.
Hey, I'm Diana.
I'm here with a very special-
(machine pops) (both scream)
- Hey, I'm Diana.
You're here watching phys-
(both laugh)
Hey, I'm Diana.
You're watching Physics Girl.
I'm here with a very special guest, iJustine.
She's-
(machine pops) (both scream)
(Justine screams)
- [Diana] Oh, god.
(Justine screams)
The person that I'm clearly torturing
in that video is Justine.
She's a tech YouTuber.
She's been on the internet forever.
She does phone reviews and the occasional cooking video.
I don't know what came over me,
but I just wanted to bring her scary science experiments.
She told me at some point
that she doesn't get scared easily.
And I thought sounds like challenge.
- [Justine] Ah, no!
(drill whirring)
- [Justine] Oh!
(drilling continues)
(Justine screams)
- [Diana] I'm here with iJustine. It's off.
- [Justine] I don't. Oh God, I don't know.
We were talking.
She's like, oh, do you get scared very easily?
I'm like, no, absolutely not.
And then you bring this over.
(orchestral stinger)
- Shout out to Justine's channel, iJustine.
Go check it out after,
but while we have her captive,
we started where all spooky videos should start.
I brought some dry ice.
- Okay. I love dry ice.
- How do you feel about nails on a chalkboard?
- I don't like it.
- Great.
(Diana laughs)
- Oh, no.
- So go ahead and touch the dry ice,
right there in the middle with the spoon.
(dry ice groans)
- Oh my gosh.
(dry ice squeals)
- [Justine] Oh!
Don't you dare!
The fork was terrible.
- That was the best reaction I could've hoped for.
- I'm traumatized.
Let's, let's let them hear.
(dry ice groaning and squealing)
- The scream happens
because the relatively hot fork
turns the dry ice straight
from a solid into a gas really, really quickly.
The CO2 expands really fast and pushes the fork away.
But then you're pressing it down.
So it goes back on to the dry ice
and then it'll push it away and back and forth.
And that sort of vibrating
back and forth will make it scream.
This only works with thermally conductive materials,
like metal.
Feel it, feel the metal, now.
- [Justine] Yeah, it's freezing.
- [Diana] It feels really cold.
- [Diana] These materials, like metal,
heat up the dry ice very quickly,
but in turn become very, very cold.
I was trying not to do this when I was starting.
- [Justine] Yeah.
- [Diana] You can see it vibrating.
- [Justine] No way!
- [Diana] Yeah.
And you can also see that carbon dioxide,
like which way is it going?
- [Justine] Yeah. It looks like it's going down.
- [Diana] It's going down, yeah.
- Since the gas is more dense than the air,
- Yeah.
- If you carefully pick up the bowl,
you can pour that into the candle.
- [Justine] No way, that'd be so cool.
(Diana laughs)
- [Justine] Let's light it back up.
(Diana laughs)
- This is my favorite reaction.
When it's like, let's do it again.
- [Justine] Yes!
(playful music plays)
- Yeah! It'll go out in there.
- [Justine] (softly) Bye!
(both laugh)
That's so great.
Okay. It's so awful.
- Justine was doing so well,
until I brought out
my favorite piece of physics equipment.
This metal bowl.
(Diana snorts)
Just kidding. The Van de Graaff generator.
That's on. Okay.
- [Justine] W- w-what, I turned around
and there's a time machine.
- This only produces 300,000 volts.
- I'm afraid to even touch it.
(Diana laughs)
- [Diana] Okay.
(Diana breathes out) (machine clicks on)
- [Justine] Oh! Oh I'm feeling weird!
- [Diana] Already?
- Yes! We haven't even started the video!
(Diana laughs)
- Actually like if you use your knuckle, it's not so bad.
(machine pops) (Diana gasps)
- If you use YOUR knuckle.
(machine pops again)
(Diana squeals)
- [Justine] Oh Gosh.
- [Diana] You can do it!
- Oh, I feel like I can feel, oh, my!
- [Diana] Yeah.
(Justine screams)
(Diana laughs)
- [Justine] It went through my whole body!
- Okay. Scale of one to ten...?
- [Justine] Okay. The...was like 45.
- I think I want you to maybe close your eyes?
(Diana laughs)
- [Justine] What is happening?
- [Diana] Okay. Open your eyes.
(Justine laughs)
- [Justine] This is incredible!
(machine pops)
(Justine gasps)
(machine pops many times)
Are you cooking her?
(Justine groans) (machine popping)
- [Diana] There we go. There's some good sparks.
- [Justine] Oh my Gosh.
- [Diana] Did you feel that? A little bit?
- [Justine] I just feel it inside of my body.
Like, my jaw is tingling.
Like, what is this?
- [Diana] This is called a Van de Graaff generator.
On the outside of this metal sphere,
it's such a high charge.
It's like 350,000 volts.
The generator causes static positive charges
to build up on the doll's hair,
but, positive charges repel each other.
So each one of the individual strands of hair
wants to get further away from the other strands.
So they stand up, they fly apart.
They want to get away from each other, essentially.
Like, if I cut the hairs of this doll,
they would fly off.
Some of these charges are coming off into the air
and we're feeling them on ourselves.
- I'm feeling a lot of things right now.
- [Diana] We tried to get our hair to stand up,
but it may have been too humid for it to work.
But what did work, was Van de Graaff levitation.
- [Justine] Wait, there's more?
- [Diana] There's more.
- [Justine] I thought we were done.
- Can you give us a little demo of the pro unboxing?
(beep)
- [Diana] These are pie tins.
Here?
It's kind of like baking with electricity.
- [Justine] Yes!
- All right.
(machine hums)
- No way! This is really incredible.
(pie tins clatter to the floor)
This is so great.
(machine hums again)
(pie tins clatter again)
(Diana laughs)
- [Diana] Yes!
- [Justine] Yes!
(pie tins continue clattering)
Incredible.
- That was epic.
- It was beautiful.
(serious, steady music)
- All right, this one's not going to shock you.
- Do you promise?
- [Diana] I promise.
- [Justine] I've lost my faith in you, now.
- The finale in my quest to scare Justine,
involved a plasma ball,
this doll.
Oh, yeah.
This is my creation.
The creepiest thing I've ever seen.
So I gouged out her eyes,
(drill whirs) (intense music stinger plays)
and I put some red tape over them.
(drill whirs again) (music stinger plays again)
And then I cut off her head
(drill whirs again) (intense music plays again)
and I-
this is not normal.
And I stuck a fluorescent light bulb up inside of her head
so that when... (laughs)
So that when you bring the tube near the plasma ball,
it'll cause the eyes to light up.
[Diana] This is the weirdest one.
Right? So I've got this doll that I brought you.
I'm just going to bring it close to....
- [Justine] Oh my?
(Diana laughs)
- [Justine] What is this?
That is super creepy. What have you done?
- [Diana] Creepiness factor? On a scale-
- [Justine] This is probably your creepiest.
- [Diana] This is just like a normal fluorescent light bulb.
- [Justine] Whoa.
Oh, that's cool!
- [Diana] Yeah. Isn't that's cool?
- That's crazy.
- [Diana] Yeah.
- [Justine] How was this happening?
- So, let me repeat.
The light bulb and the doll's head
is not connected to anything.
It's just inside the doll.
And it turns on
when we placed the doll near the plasma ball.
You don't even have to be touching it.
The way this all works
is that the center of a plasma ball has a lot
of electrical energy in the form of an alternating voltage,
but some of the energy escapes and smacks into the gas
inside the fluorescent light bulb,
knocking off electrons from the atom in there
and in the process emitting light.
- [Justine] This is something I'll never forget.
- [Diana] who could forget?
- [Justine] I wish that I could.
(Diana laughs)
Thank you guys so much for watching this video.
I mean the MVP right here, is Justine.
It was just great to see her reactions to the creepy stuff,
but also like how cool you thought the science was.
- It was really fun. Yeah.
Thanks for bringing me into your world.
- Go check out the video on her channel.
We made a video where we tried a bunch of kids science kits
that you can get off the internet,
including digging for gems!
Out of, out of a plaster gem set!
I'll link to Justine's video in the description
and the end cards and so forth.
Let me know if you guys like this format,
where we have a guest on
and we bring them into our world of physics.
And if there's any guests,
anyone specific, you'd like to see on Physics Girl.
Thanks so much for watching and happy physics.
Oh, no. Lost my microphone.
I'd like to thank Audible for supporting PBS.
Audible's collection of audio books includes
audible originals,
audio titles created by storytellers
from around the literary world.
For example,
you could check out "The 3-Day Effect",
an audio book all about how
spending more time out in nature is better
for your health and happiness.
You could even listen to it while walking outside.
For more information,
go to audible.com/physicsgirl
or text physics girl to 500-500.
Members own their own books and can access them anytime.
For more information,
go to audible.com/physicsgirl
or text physics girl to 500-500.
(happy, upbeat music)