Fin and Snoot calculate the length of their new cars, using feet, centimeters and meters.
NARRATOR: Hello Snoot, what鈥檚 that you鈥檙e driving?
ALIEN: (Alien language)
NARRATOR: I see, you hired a go-kart from the intergalactic market.
Hello Finn.
ALIEN: (Alien language)
NARRATOR: What an impressive car. On Earth, that鈥檚 called a limousine. It鈥檚 a lot longer than Snoot鈥檚 go-kart isn鈥檛 it?
How long is it exactly?
ALIEN: Eh
NARRATOR: I鈥檝e got an idea, you can estimate the length in steps.
The go-kart is ten steps in length and the limousine is 30 steps in length.
30 is three times ten. That makes the limousine three times longer than the go-kart.
ALIEN: (Alien language)
NARRATOR: I know Snoot. Counting things out in steps isn鈥檛 very accurate, it just gives you an estimate of how long things are.
If you want to know exactly, you鈥檒l have to use a tape measure.
On Earth we use centimetres to measure quite small lengths, like the width of a tire, or the diameter of a wheel.
And we use metres to measure longer lengths, like the length of a car.
ALIENS: Ah ha!
NARRATOR: So, according to the tape measure, Snoot鈥檚 go-kart is two metres long, and Finn鈥檚 limousine is six metres long.
Six is three times two, so your estimates were right!
The limousine is three times longer than the go-kart.
Hello Plimble.
ALIEN: Hello.
NARRATOR: I see you hired a monster truck. I think we are going to need a bigger tape measure.
How do you estimate the length of something?
Estimating means you work something out roughly
A good way of estimating a length is to measure it with part of your body:
- for short lengths try your hand span
- for something a bit longer try using the length of your feet
- for something even longer try using your arm span or steps
How do you measure length accurately?
To measure something accurately you should use standard units
You should use different units for different lengths:
- millimetres (mm) are good for very small lengths - like the width of a pencil or your finger
- centimetres (cm) are good for something a bit longer - like the length of a pencil or a book
- metres (m) are good for something even longer - like the width of a room or the length of building
- kilometres (km) are good for longer distances - like the distance between home and school, or between different towns
You should use proper instruments to measure accurately, like a ruler, tape measure, metre stick or trundle wheel.
More on Measurement
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