ShmoopTube

00:13

Whether we think about it or not, we’re constantly measuring things. [Girl next to a measuring scale drawn on a wall]

00:16

There are the obvious ones, like who’s taller –

00:19

--or who has bigger feet…

00:20

--and the less obvious ones, like who can bawk like a chicken the loudest… [Man in a chicken suit]

00:24

Yeah…we think we've got that one on lock. [Woman puts her thumbs up]

00:27

Another unit of measurement? [Teacher at the front of a class]

00:29

Time.

00:30

When you look at a clock to see how much time is left in math class, you’re measuring time. [Clock ticking]

00:34

Time can be measured in seconds, minutes, hours…

00:37

… as well as days, months, and years… [Coop pointing at a blackboard]

00:39

… which is sometimes how long it seems like math class lasts. [Students crying in class]

00:42

We can also measure things like the temperature to know how hot or cold it is outside.

00:47

Temperature is measured in degrees Celsius or Fahrenheit – and it’s important to [Thermometer]

00:50

know which you’re measuring in.

00:52

That’s because 40-degrees Celsius is over 100- degrees Fahrenheit. [Dino pointing at a blackboard]

00:56

So if you tell someone to pack for 40 degree whether and forget to mention it's Celsius…well…you

01:00

might have one hot-headed friend.

01:01

Literally. [Man with a surfboard and man wearing a winter coat]

01:03

There are also two kinds of systems for measuring things like distance and weight.

01:07

Right now, we're going to cover the metric system.

01:09

The metric system of measurement is used… well, almost anywhere you can measure.

01:14

The metric system divides things into liters, meters or grams – which are called “base units." [Coop pointing at a blackboard]

01:23

And just like a day can be divided into hours, minutes or seconds – each base unit in the [Stopwatch]

01:27

metric system can also be divided up. [Arrows pointing to the different units on the stopwatch]

01:29

We do this in units of ten, with each unit corresponding to a prefix.

01:33

From largest to smallest, those prefixes go “kilo-”, “hecto-”, “deca-”, “deci-”,

01:38

“centi-” and “milli-”.

01:39

Let’s see how we can convert our metric measurements, to go from, say, a meter to

01:43

a millimeter.

01:44

First, we need a guide or scale of some kind. [Doctor appears]

01:46

For that, let's bring in our special guest star, Jane. [Little girl walking in]

01:49

Here’s Jane.

01:50

Jane is one meter tall.

01:52

But with our metric prefixes, and knowing that

01:55

everything gets divided into tens, we could go up the measurement scale and say that Jane

01:59

is point-one decameters, point-oh-one hectometers or point-oh-oh-one kilometers tall. [Hand pointing to the different units]

02:04

Or, going down the scale, we could say Jane is ten decimeters, one-hundred centimeters,

02:09

or one-thousand millimeters tall.

02:11

Get it?

02:12

And now we have a guide we can use to do any conversion we want! [Doctor pumping their arms in the air]

02:15

Thanks, Jane.

02:16

We can then put those measurements into fraction form.

02:19

And now we have ratios to use for our conversions.

02:22

Want to know how many kilometers you’ll have to walk for that 3000 m trip?

02:26

Just make 3,000 the numerator of the “kilometer” ratio…

02:30

… and we get three thousand over one thousand.

02:33

Or, 3 kilometers.

02:35

And there you go!

02:36

Metric conversion in a nutshell.

02:38

We don't recommend you do metric conversion in a nutshell though. [Mans face in a nutshell]

02:40

That sounds kinda cramped. [Teacher at the front of the class in a nutshell]

Full Transcript