H9 'Measuring' -- Prior knowledge + §1

• Wiskunde
• Middelbare school
• vwo
• Leerjaar 1

Today, you will learn ...

... what a quantity is and what a unit is.

... how to convert units (of length).

... what the term scale means,

    and how to use scale.

CHAPTER 9:    Measuring

Would you like to swim in a big pool on your holidays? Then you will love the San Alfonso del Mar resort in Chile. This resort has the biggest swimming pool in the world! The swimming pool has a length of 1.013 metres, an area of 8 ha and is up to 35 metres deep. 

The pool contains 250 million litres of filtered sea water from the Pacific Ocean, wich is nearby. The water is heated by the sun and its temperature can be up to 26 °C.

Something you measure is called a quantity.

A quantity is measured using a unit.

Quantities
and units

Quantity	Measuring instrument	Unit
	measuring jug	litre
time
	a scale
length
		degrees Celsius

stopwatch

weight

ruler

centimetre

seconds

volume

thermometer

grams

temperature

Units of length

23 m = ... cm

23 m = ... cm

23 m = 230 dm

230 dm = 2300 cm

82 hm = ... km

82 hm = ... km

82 hm = 8.2 km

23 · 10 · 10 = 2300

82 : 10 : 10 = 0.82

Start making exercises 1-5

Scale

A scale of 1 : 200 means the measurements of the real object are 200 times as large as those of the model.

Scale

Use a scale of  1 : 200

- If the scale model of a bridge is 150 cm long,

   how long is the real bridge?

- How tall is the scale model of a house that is    9 metres tall?

150 x 200 = 300,000 cm 

                  (= 3 km)

9 : 200 = 0.045m 

(= 4.5 cm)

Today, we have learned ...?