Hi, I'm Dianna.
You're watching Physics Girl.
And in this video, I have a super special guest.
Her name is Simone Giertz.
And I'm sure that you've seen her
somewhere with her amazing, hilarious robots.
Simone agreed to answer some physics riddles on this video.
And I hope you're not mad about this
because I know you love getting the answers right away.
But the first riddle is in this video.
And then you have to come back tomorrow
to get the answer to the riddle and to get the next riddle.
So here's the video.
All right.
Physics is serious.
We need to put on our serious faces.
Can you tell my viewers like what your channel is?
You do robotics.
I'm not sure I can tell anyone what--
it's a weird mix.
But I do some sort of like robot comedy.
So I build robots that don't work really well.
I build these like kind of useless machines
as a way of entertaining people.
Check it out.
But not before you watch this video.
Oh, I will put a link in the description.
But little known fact, you studied physics in school.
But I dropped out after a year.
I'm sorry.
So we're going to bring you back into the physics world.
And I've got some physics questions for you.
This makes me really nervous because I
feel like I will finally be caught
with not being super smart.
Because I was a straight A kid in school.
I was a total teacher's pet.
And then like somehow in my like mid-twenties,
it just started going downward.
[COUGHING]
I need some physics CPR over here.
Are you ready for the first question?
Here's a little warmup.
It's something a little bit more mechanical,
so I think you may be a little more familiar.
So bicycles have a left-handed screw somewhere on the bicycle.
Where do you think it is?
And why do you think it's there?
Pause here if you want to think about the question for a second
before we go on.
On the pedal because when you pedal it can't unscrew itself.
Yes.
Really?
Yes.
You didn't know, you didn't know that?
I'm not that stupid.
No.
I was thinking that the only reason you need a left hand
screw is so you don't unscrew it.
OK, maybe not everything is lost.
No, that was really good.
That was really good.
Which pedal?
Do you have any idea?
So it's righty tighty--
I always think of like if you go against the time--
so the time goes like that.
For the viewer, it would be--
The clock?
The clock, yeah.
You have a screw loose.
And so that's how you [INAUDIBLE] that's
like my own "righty tighty."
But I know here in the States, people
do "righty tighty, lefty loosey."
But that doesn't rhyme in Swedish, I'm guessing.
So I guess it'd be on the--
It'd be on the left side from the person's perspective.
I don't actually know the answer.
The answer is the left side.
But the explanation as to why is actually not
that straightforward.
So if you have an explanation, leave it in the comments
or tweet it at Simone.
Tell her I sent you.
That was really impressive.
It's all I want is to impress you.
It's all I ever wanted.
I'm really proud of you, as if I had anything
to do with your success.
We're done with the warmup, on to the riddles.
Ooh!
That was the warmup.
OK.
Are you ready?
Yes.
You've got two spheres, two balls,
that are different materials.
So say one is like made of iron and one
is made of wood, where one is lighter than the other.
But they are the exact same size.
You drop them from a really, really tall height.
So say you drop them out of a plane or something.
Which one experiences the higher force
of air resistance, once the balls reach terminal velocity?
If they have the same surface and they're treated with
say, a coat of epoxy.
Right.
OK, so imagine that they are treated
with a coating of epoxy, and so they have the same surface.
Are they the same size?
They're the exact same size.
But one is heavier than the other.
And this is where I tell you to come back tomorrow
for the answer.
It's like vegetables.
I know that you don't like them, but they're
so good for your brain.
But in the meantime, I will be on Facebook.
I'll be on Twitter.
I'll be in the Comments, if you have
questions about the questions, or if you just want to say hi.
Please say hi.
Thank you for watching.
And check out Simone's channel.
And happy physics-ing.