Scale drawing

By Zani Alam

Once I was asked by my teacher to draw a picture of a CD. I grabbed a ruler, measured out all dimensions (width and height) carefully. Then I drew the CD based on those dimensions. This is was an easy task. Then my teacher asked me to draw my bedroom. I thought this would be difficult but once the teacher explained to me about scale drawing and gave some examples, it became an easy task for me. I just had to give my self a chance to listen to the explanation and to investigate more about scale drawing.

Fish

ScaleA weighing machine

The numbers on a measuring instrument

Rust and flaky chemicals on metal are called scales

2- The ratio or proportion of size on a

map or diagram

This type of scale we are going to look

at today

Meaning of the word scale in everyday life

Scale 1-A weighing machine

2-Fish have scales

5- The numbers on a measuring instrument used to make reading

4-Rust and flaky chemicals on metals are called scales

3- The ratio or proportion of size on a map or diagram

This is the focus for our lesson.

A Scale drawing

Can be shown as fraction: 1/100 or ratio

1: 100

Gives the ratio that compares the

measurement of the drawing with the actual

measurements.

Scale

Is a proportional 2 dimensional

drawing of an object .

A Scale drawing

A scale model

Can be shown as fraction:

1/100 or ratio1: 100

A scale factor

Gives the ratio that compares the measurement of the drawing with

the actual measurements. Scale Is a

proportional 3 dimensional model of an

object.

The number of times the original has

been reduced or enlarged e

Is a proportional 2 dimensional

drawing of an object .

In scale drawing there are two types of problems:

The second type involves

making a scale drawing of an

object.

The first type type involves

calculating the real sizes of objects from the drawing.

A- The scale on drawing is 1:100. What is the real distance between two points that are 5 cm apart on the drawing.

1- Calculating the real sizes of objects from drawing

1:100

Means 1 cm on the drawing represents 100 cm in real life

1 cm on the drawing 100 cm in real life

Real distance: 5x 100 = 500cm =5m

1cm =10mm

House designPool design

Scale drawing

Connections with the real worldScale drawings are everywhere!

1.5 m 15 cm

Why scale drawings?If it's just a small object that you want to represent on paper, full size drawings are great. But, if you want to draw, say, a room with furniture, you're going to need a huge piece of paper to sketch it. As you know, we don't do this. We do "scale drawings" - we make our sketches smaller so they can fit on one sheet of paper.

Why do we need to use scale to draw objects or house plans etc.?

We can't fit the true measurements onto a piece of paper.

The ratio 1cm:100cm means that for every 1cm on the scale drawing the length will be 100 cm in real life

Plans and maps use a scale. The scale is written as a ratio.The first number in a ratio represents the drawing, while the second number represents the real object.

Example:

1:100

DrawingActual length(Real object)

Drawing length: Actual length

to

An objet and its scale drawing are similar figures.Two objects are SIMILAR means that they are identical in shape, but not in size.

• This house drawing measures 10 cm in length.• The scale used here is 1cm:250cm (2.5m)• This means that every centimetre on the

drawing actually represents 2.5 metres length in real life.

If the house (drawing) measures 10cm in length what is the true length of the house?10x250=2500cm =25m25m is the true length of the house.

Station 2

Station 3

Station 4

Station 1

Scale drawing stations

(46 to 91 meters) in width(91 to 119 meters) in length

Soccer is played on a rectangular field

Terry used a scale of 1 cm representing 1600 cm (16m) when he drew this scale drawing of a soccer field. (1:1600)What are the dimensions of the soccer field?The length of the soccer field is already measured for you.

Answer the following questions:The length of the field in the scale drawing (on the diagram) is ______ cm Each centimetre means ______ in real life. Real length of the soccer field= The width of the field on the diagram is ________ cm Real width of the soccer field is __________________

Station1

Terry used a scale of 1 cm representing 1600 cm (16m) when he drew this scale drawing of a soccer field. (1:1600)What are the dimensions of the soccer field?The length of the soccer field is already measured for you.You need to use your ruler to measure the width.

The length of the field in the scale drawing (on the diagram) is 6cm. Each centimetre means :1600cm in real life or 16 m Real length of the soccer field= 6x1600= 9600cm= 96 m The width of the field on the diagram is :3 cm Real width of the soccer field is :3x1600=4800cm = 48m

Station1answers

Station2Calculate the real size of each item:

A) Scale: 1cm represents 200cm (1:200)Use your ruler to measure the length of the flag.Answer:1- The length of the flag on the drawing is:___________

2- Each centimetre on the drawing represents 200 cm (2m) in real life.

3- Real length =______________

B) Scale: 1cm represents 15 cm (1cm: 15cm)Answer:1-The length of the bike on the drawing is:_____________

2- The real length of the bike is:_______

Station 3 1- Vocabulary with scale drawingFill in the missing words using the following: Real life - Drawing-Actual -Ratio-Big-Scale1- A scale drawing is a _________ that compares the measurement of the drawing with the __________ measurements.2- When we want to draw ______ objects we use ______ drawing. 3- A scale of 1cm: 100m means every cm on the __________ represents 100m in ______ ________.

1- Real life application with scale drawing

Scale drawing

Pool design

Scale: 1:20

What is the length of the bed on the diagram:__________

Real length:_____________

What is the width of the bed on the diagram:___________

Real width:_______________

Station4