1.3 How long is a piece of string?

Mathematics

Grade 9

Numbers

Module 4

How long is a piece of string?

CLASS WORK

1 Work in a group to answer the following questions:

1.1 How many metres is a thousand millimetres?

1.2 Which units are the best for giving the following quantities? Some are difficult, and you may have to do some research and bring a better answer back later.

1.2.1 How tall you are.

1.2.2 The distance between our sun and the nearest star.

1.2.3 How long it will take to walk from Cape Town to Cairo.

1.2.4 The amount of milk you drink in a year.

1.2.5 The quantity of vitamin C one has to take in daily.

1.2.6 The temperature of a patient in a hospital in New York.

1.2.7 The area of Greenland.

1.2.8 The speed of a car on the open road.

1.2.9 The amount of wood a cabinetmaker orders at one time.

1.2.10 The total amount of money the government collects in taxes in a year.

end of CLASS WORK

PROJECT

The passing of time.

• We use watches and clocks to show how time passes.
• Do the following questions as a project. Don’t make yourself guilty of plagiarism.

1 Explain the difference between analogue and digital clocks / watches.

2 List all the clocks in your home, and say whether each is analogue or digital.

3 Find at least one other method used to measure time or show the time – one that is not generally used in western culture. It can be something from earlier times, or something from another country. Try to find something about timekeeping in Africa. Explain clearly how it works.

• The project must be handed in on: ..................................................

end of PROJECT

HOMEWORK ASSIGNMENT

1 Complete any remaining questions from the class assignment above.

2 What measuring instruments are used for the following measurements?

2.1 How tall you are.

2.2 The mass of a new–born baby.

2.3 The amount of milk you have to add, in a recipe.

2.4 The paint used for painting the outside of an ordinary house.

2.5 Humidity.

2.6 The speed of a moving car.

2.7 We have a very complicated way of determining leap years. Find out:

2.7.1 Why we need to have leap years, and

2.7.2 Which years will be leap years.

end of HOMEWORK ASSIGNMENT

Connecting with the world – ASSIGNMENT

• Choose one of these questions to do.

1 You’ve just discovered your granny’s old recipe book. You remember some of her recipes, and you’d like to try them too. Unfortunately it uses old–fashioned units, which would be a lot of trouble to convert each time. Decide how you can make some kind of aid, like a table of graph or formula, to make conversions easier. The units that occur often are: the temperature of the oven is given in °F; the measures of mass are in ounces and pounds and the liquid measures are in pints.

2 Your father has just bought you a second–hand car, but it was imported from America and all the instruments use units you are unfamiliar with, and have difficulty making sense of. Decide how you can make some kind of aid, like a table or graph or formulae that you can understand exactly what units like miles, gallons, miles per gallon (petrol consumption) mean in our units.