Introduction to structures

Technology

Grade 5

Discovering structures

Module 10

Introduction to structures

BACKGROUND

Any object is a structure of some kind. Consult the dictionary to find the meaning of the word and write it down.

Assignment 1

What are structures used for?

Write down the answers in your workbook or on a sheet of paper : (Select from the following possibilities: bridge, a room, basket, cardboard box for apples, bookshelf)

A structure: a) contains objects, e.g. _ and/or

b) protects objects, e.g. _ and/or

c) supports objects, e.g. _ and/or

d) encloses space, e.g. _ and/or

e) stretches, over a distance, e.g. _

[LO 2.1]

A house is a structure that performs all the above functions. It contains furniture, protects its inhabitants and their possessions, supports the roof, encloses space and covers a certain area or surface.

Assignment 2

A structure must be able to support its own weight, as well as the mass that it has to carry, while still retaining its shape. A mass can be an object, a person, or a force. What is the mass in each of the following examples?

[LO 2.1]

Assignment 3

How forces influence structures

What influence does a force have on a structure? Copy the complete sentence in your workbook or on a sheet of paper and supply the missing words.

1. It _ move objects.
2. It _ objects to move.
3. It changes the _ of movement.
4. It changes the _ of movement.
5. It changes the _ of objects.

[LO 2.1]

Assignment 4

The influence of a force is not always visible.

What are the causes of the main forces influencing parts of structures? Copy the senctences and supply the missing words (See assignment 2).

1. The _ that are brought to bear on the structure.
2. The _ of the structure itself.

[LO 2.1]

Assignment 5

Which two forces influence structures? Copy the sentence and supply the missing words:

1. 

   _ compresses part of a structure, attempting to push the sides closer together.

1. _ stretches part of a structure, trying to separate parts from each other.

We say that part of the structure is in a _ or _ form.

The poles are compressed,or pressure is exerted.

The walls of the house are compressed, or pressure is exerted.

The chains of the swing are pulled,or pressure is exerted.It is called a tensile force.

The long chain and the two shorter links of this signboard are pulled,

or pressure is exerted.It is called a tensile force.

[LO 2.1]

Assignment 6

A force that affects a structure, may cause the parts of the structure to collapse or lose its shape. Now copy the following sentences and supply the missing words:

A part’s resistance to a change of its shape, depends on

a) the _ of which it is made,

b) its _

c) its _

d) and the _ in which you try to bend it.

Structures should be _ , _ and _ so that it will not collapse or overturn when you place any kind of mass upon it.

[LO 2.1]

Assignment 7A

Let’s investigate the vertical strength of shell structures:

Note to the teacher:

Divide the class into groups. Provide each group with six A4 Manila’s of the same thickness, a can containing some nails, and a piece of flat, sturdy cardboard measuring 10 cm by 10 cm.