Kind: captions
Language: en
What is the difference between mass and
weight? I think it's something that a
lot of people are confused about. They
just think that anything that's big,
like this car, has a lot of weight. It's
very heavy. It's got a lot of mass. And
people just basically think of these uh
ideas as all the same. But there's an
important distinction between the terms
mass and weight. Mass refers to the
amount of matter in an object, whereas
weight is a force. It's the
gravitational attraction that the object
feels towards, in this case, the Earth's
center. So, I've got a little experiment
uh today where I brought my car out
here. I'm going to ask some people, why
is it difficult to push my car? And my
bet is their answer will be because the
car is heavy.
Cuz it's heavy.
Cuz you're in heavy. It depends if it's
uphill or downhill, but you know, the
car is heavy.
Big rock, you would think would be
heavy. Anything that's big, you would
think would be heavy. It's too heavy.
Heavy.
Oh, it's a bit lighter than I thought.
It's got its weight.
Weight is responsible.
What is weight?
Weight is mass of inner gravity.
What? What is this gravity thing?
Gravity is
the pull of this core of the earth.
Your car is pulled towards the the
center of the earth.
Yes.
But now when you push it, let's say
you're pushing your car, you're not
pushing it up. Do you know what I mean?
No.
But it's still hard to push.
Yeah.
So, do you think weight's responsible
for making it hard to push?
Well, it is weight. I mean, like, you
know, the lighter the car, the easier it
is to push. So, yeah.
Like weight only
gravity on the mat.
But I'm not trying to lift the car,
right? I'm just trying to push it.
That's really big rock you would think
would be heavy. Anything that's big you
would think would be heavy. So a car.
But I'm not lifting it. I'm pushing it.
So it's the gravity of it, I suppose.
But this is this is my question, right?
But I'm not trying to lift it.
No, that's true.
But it's still it's still hard to push.
So why is that? Because like if I lift
it, I understand you saying it's heavy.
Yeah.
And that it would be really hard, but
we're pushing it and we're actually
getting it to go.
True. True.
So how does that work?
The answer is because the car has
inertia. Inertia means that objects with
mass have a tendency to resist changes
in their motion. I thought she had a
great answer when I started, which was
inertia. Can you tell us about that?
What is what's inertia?
Just like once something's stopped, it
doesn't really want to go. And once
something's going, it doesn't really
stop.
Yeah. Well, the idea that I'm trying to
get at is there's actually two different
things, right? One thing is that there's
a force pulling the stand into the earth
and that's what we call weight and that
makes it impossible to lift. But there's
something else which is called inertia.
And that means something is difficult to
change its motion. The car's got a lot
of inertia. And that's why it's
difficult to push, which is different
than why it's difficult to lift, which
is the weight force pulling it down
towards the earth.
Fair enough. But it's actually not as
difficult to push as.
It's not that hard. Yeah. [laughter]
I know. It doesn't even prove my point
cuz I You can push it with one hand,
can't you? Absolutely.