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## Unit conversion

Current time:0:00Total duration:5:10

# U.S. customary and metric units

CCSS Math: 5.MD.A.1

## Video transcript

We're asked to sort the
following units of measurement into two categories:
U.S. customary units and metric units. So these are just two different
systems. You'll get more and more familiar
with them. Then indicate whether each unit
measures length, weight, mass, or volume. Let's do the first. Let's see
which of these are U.S. customary unit versus
metric units. So the liter is a metric unit. You would use it in
the metric system. A gallon is a U.S.
customary unit. We've been dealing with that. If you fill your gasoline in
Europe, you're going to be filling it in terms of liters. In the U.S., you're going
to be filling it in terms of gallons. And we're going to talk about
whether they're units of volume and whatnot
in a little bit. Decigram, that is
metric system. In general, whenever you see
these prefixes, deci, centi, kilo, you're dealing with
the metric system. No one ever talks about
a kilopound. I guess you could, but no one
really talks about it. Same thing, millimeter. This is metric system. A gram is metric system. Meter is metric system. The foot is a U.S.
customary unit. We'll talk about whether it's
distance or any of that in a little bit. Kilogram, once again,
it is metric units. In case you haven't gotten what
I'm doing here, blue for metric, red for U.S. customary
units, or I guess magenta. Centiliter, that is metric. Centimeter, meters are metric. And notice we have the
prefix in both cases. Centi means 1/100. Cup, that is U.S.
customary units. I have to do that
in the magenta. Cup, U.S. customary units. Meter, that is the
metric system. Pound, U.S. customary units. It's getting a little tedious. Inch, same thing, that's what
we use in the U.S. Ounce, we use that in the U.S. And then
the yard, we also use that in the U.S. Now we've divided them up. All the magenta ones are used
in the U.S. All of the blue ones are used really in the
rest of the world, and actually some places in
the U.S. as well. I think a lot of the world is
frustrated that the U.S., that we're not all converted to this
because the metric system is actually a little
bit more logical. It's easy to just figure out
what it's saying, and we'll deal with that in more
detail in the future. Now the next thing we to
figure out is whether something is a measure of
length, weight/mass-- and they're not exactly
the same thing. Mass is how much of a substance
you have. Weight is how much force with
which gravity is pulling on that mass. And it would change depending
on what planet you're on. But on Earth, they tend to be
used interchangeably, so we'll use it roughly interchangeably
here. And then you have volume,
or how much space something takes up. So this is distance. This is moving in
one dimension. Mass is how much
stuff there is. Weight is how much the force
that stuff is pulled on, on a planet, by gravity, or I
guess a star anywhere. And volume is how much space
does that stuff take up. Now let's think about it. Liter is volume. This right here is volume. How much space do you take up. Gallon is also volume. That's in the U.S. And in
Europe, or in the metric system, it would be a liter. That's a gram. Gram is a unit of mass. So decigram just means
1/10 of a gram. Millimeter. Meter is a unit. Meter right here, that is the
unit of distance or of length. Millimeter, milli means
1/1,000 of a meter. Foot, that is also
a unit of length. Kilogram, that just
means 1,000 grams. Kilo means a thousand. Gram, we already said,
is a unit of mass. Centiliter, that means
1/100 of a liter. Liter, we already figured out,
is a unit of volume. Centimeter, we already
figured out. Meter is a unit of length. Centimeter means 1/100
of a meter. So this is a unit of length. Cup, we've seen multiple
times already. It is a unit of volume,
how much space does something take up. Meter, that is length. We've seen it multiple
times already. Pound, that is actually
a unit of weight. An inch is a unit of length. We're all familiar with it. An ounce-- you have to be
careful here-- if someone just has an ounce, that is
1/16 of a pound. It as a unit of weight. If it was written fluid ounce,
then we'd be talking about 1/16 of a pint, and then it
would be a unit of volume. But since it's just ounce,
it's a unit of weight, 1/16 of a pound. And then finally, a yard
is a unit of length. And we are done.