FOCUS QUESTION
How
do I use the various measurements around me?
SPECIFIC OBJS.
CONTENT SUMMARY
In plain English, a scale drawing is a drawing which has been reduced or enlarged from its original size, to a specified scale. The scale is a ratio of the size of the drawing to the size of the original object being drawn. This may be referred to as a scale ratio.
ENGAGE
Students. I want us to all turn to the Map of Jamaica.
Before we go any further, what are the four things found on a map?
Title
Compass
Key
Scale
Now look at what the scale says.
I want you to use your ruler and measure the distance between the following places in cm.
Black River to Santa Cruz
Santa Cruz to Christiana
Portmore to Harbour View
Do you believe the distances you got for these places could be the actual distances of these places?
Of course not. The real length of these places could never hold in this Atlas.
This is why we need what is called a SCALE to represent these actual lengths.
We will be looking today at SCALE DRAWING.
EXPLORE
Let us listen to the video clip on scale drawing below, to learn more about it.
Video clip: Scale Drawing
In SCALE DRAWING, the first term refers to the length of the scale and the second term refers to the length of the actual object.
Now let us go back to the places you measured earlier on.
Using a scale of 1cm = 30 Km , find the actual distance of each place.
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EXPLAIN
What is meant by SCALE DRAWING?
Explain what the first and second term on the scale of a map represent.
When in other real life situations is scale drawing used?
EXTEND/ELABORATE
Use your ruler and the scale below to answer the questions that follow.
By now you should have noticed that one box in the grid actually represents 1 cm.
(a) What is the actual distance from Super Shop to Hotel Sun?
(b) What is the actual distance between Beach Bistro to Grooves Night Club?
EVALUATE
1. The distance between two towns is 8 cm. Using a scale of 1cm: 500 km, calculate the actual distance between the two towns.
2. Complete the table below, using the scale 1cm: 20 km.
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Places |
Measurement |
Actual Distance |
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Kingston to Morant Bay |
20 cm |
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Santa Cruz to Christiana |
3 cm |
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Black River to Lacovia |
2 cm |
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3.
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