2.1 Modern measuring instuments

Technology

Grade 5

Graphic communication

Module 5

Modern measuring instruments

Measure and draw with modern measuring instruments

Assignment 1:

Dimensions

[lo 1.3]

Measure the lengths in mm of the indicated line sections in the following sketch.

Which measuring-instrument is the most suitable?

Hint for the Teacher:

Allow a margin of ± 2 mm to both sides, but encourage learners to measure accurately all the same.

Background:

What is a line section?

The line sections used to compile the sketch above are mainly HORIZONTAL, VERTICAL, DIAGONAL (slanting) or CURVED.

What is a horizontal line?

What is a vertical line?

What is a diagonal line?

What is a curved line?

Assignment 2:

Look at the sketch at assignment 1 and answer the following questions

[lo 1.3]

1. Write down the letters of any three horizontal lines in the sketch.
2. How many diagonal lines are there in the sketch?
3. Write down the letters of any two vertical lines in the sketch.
4. Draw over the HORIZONTAL lines in red, the VERTICAL lines in blue and the DIAGONAL lines in green in the sketch.
5. What kind of line is (k)? Can you measure the length of (k)?

How?

Assignment 3:

Drawing lines with instruments

[lo 1.3]

Using a ruler and the four kinds of lines, design and draw any object on squared paper.

Assignment 4:

Drawing of lines using instruments

[lo 1.8]

a. Draw a horizontal line of 50 mm with your ruler. Follow the instructions

1. Draw a horizontal line across the page (about 150 mm).
2. Make a little vertical mark on the left of the horizontal line.
3. Place your ruler on the mark.
4. Measure 50 mm and make a small vertical mark on the right.
5. Write 50 mm under the measured line section.

b) Draw a diagonal line of 70 mm with your ruler. Follow the instructions given above.

Assignment 5:

Proportion

[lo 1.3]

Draw a line parallel to each of the following:

Background:

Complete: The point where two lines meet, is called a .The size of an angle is measured in DEGREES and we use a PROTRACTOR to measure the size of an angle.

When a vertical line meets a horizontal line perpendicularly, a __ is formed. The size of such an angle is 90 ^o .

A line section can also be called a STRAIGHT ANGLE. The size of such an angle is 180 ^o .

When an angle is between 0 ^o and 90 ^o , it is called an ACUTE ANGLE and when an angle is between 90 ^o and 180 ^o , it is called an OBTUSE ANGLE.

Assignment 6:

[lo 1.2]

Write down what kind of angle each of the following is:

Hint:

Turn the page so that one side of the angle is horizontal, and decide then.

Assignment 7:

Draw two examples of each kind of angle with your pencil or ruler.

[lo 1.3]

a. A right angle

b. An acute angle

c. An obtuse angle

Background:

If we combine certain line sections with the above-mentioned three angles, we get GEOMETRICAL FIGURES. They are also called two-dimensional shapes, because they are flat shapes or planes. Lines that are one-dimensional are used in drawings to form two-dimensional shapes or planes. Most two-dimensional figures have two dimensions, namely length and breadth.

Assignment 8:

[lo 1.2]

Can you recognise these basic geometrical figures?