Here is what the KICD curriculum design asks for in Scale Drawing, with a sample lesson plan, notes and an exit check you can read before you teach. In Fuma, the same lesson comes out of your own scheme of work, starting from the lesson your class has reached and dated to your term.
Aligned to the KICD curriculum designSample — review before you teach
What learners should be able to do
Specific learning outcomes, word for word from the KICD curriculum design.
a)represent length to a given scale in different situations
b)convert actual length to scale length in real-life situations
c)convert scale length to actual length in real-life situations
d)interpret linear scales in statement form in different situations
e)write linear scales in statement form in different situations
f)interpret linear scales in ratio form in different situations
g)write linear scales in ratio form in different situations
h)convert linear scale from statement form to ratio form, and ratio form to statement form
i)make scale drawings in different situations
j)apply scale drawing in real life situations
k)recognise the use of scale drawing in maps
Key inquiry questions
How do we determine scales in real life?
Where do we use scale drawing in real-life situations?
A sample lesson plan: Scale Drawing: Drawing Classroom Objects to Scale
This is a sample. Read it and change it for your class before you teach it. In Fuma, everything stays a draft until you approve it.
Grade 8 · Mathematics · 40 minutes
explain that a scale drawing reduces or enlarges every actual length by the same ratio
make scale drawings of classroom objects using a given statement scale
appreciate the use of scale drawings in maps and building plans
A sample lesson plan
Time
Teacher
Learners
Introduction5 min
Teacher:
Show a digital map on tablet; zoom in and out
Ask: Why does the same road look longer when zoomed in?
Remind learners: You already know how to measure length with a ruler
State lesson focus: drawing big objects on small paper
Learners:
Observe map zoom changes
Discuss in pairs why size on screen changes
Share one idea with class
Measure the Real Desk10 min
Teacher:
Group learners in fours
Give each group a metre ruler and a desk
Instruct: measure desk length and width in cm
Record one group's measurements on board
Learners:
Measure desk length end-to-end with ruler
Measure desk width from edge to edge
Record measurements in exercise books
Compare with another group's measurements
Draw the Desk on Grid Paper10 min
Teacher:
Give each learner 1 cm grid paper
Use measured values, e.g. actual length 120 cm and width 60 cm
Say: Use scale 1 cm represents 20 cm
Model dividing: 120 ÷ 20 = 6 cm, 60 ÷ 20 = 3 cm
Instruct: draw a 6 cm by 3 cm rectangle
Learners:
Divide each actual measurement by 20
Mark 6 cm length and 3 cm width on grid
Draw and label the scaled rectangle
Write the scale under their drawing
Read and Write the Scale10 min
Teacher:
Write the statement scale and ratio: 1 cm represents 20 cm = 1:20
Ask learners to copy both forms
Show three drawing lengths; ask which matches a drawing for a 160 cm table at 1:20: A 8 cm, B 12 cm, C 16 cm
Ask: How do we know A is correct?
Learners:
Write statement and ratio forms in books
Calculate 160 ÷ 20 mentally
Choose A and justify
In pairs, write scale for a 40 cm book drawn as 2 cm
Shown: the first 35 minutes of the 40-minute lesson.
Sample teaching notes
Teaching notes are for you at the board: the subject knowledge and what to watch for.
Content Mastery — what you need to know one level above Grade 8
Why division and not subtraction.
A scale drawing is an example of similar figures: two shapes with equal angles and corresponding sides in a fixed ratio. In a rectangle, equal angles are automatic, so the only thing that can go wrong is the side ratio. If the real desk is 120 cm by 60 cm, its sides are in the ratio 2:1. A correct drawing must also have sides in the ratio 2:1, whatever its size. Dividing both lengths by 20 gives 6 and 3 — still 2:1. Subtracting 20 from both gives 100 and 40 — a ratio of 2.5:1, which is a different shape. Subtraction changes the ratio; division preserves it. That single sentence is the correct answer to 'why divide?', and it is worth saying aloud in exactly those words.
The scale factor. Dividing by 20 is the same as multiplying by the scale factor 1/20, so for a reduction the scale factor is less than 1. So 120 × 1/20 = 6. This is the same operation as 120 ÷ 20, and showing it once on the board links this lesson to the fractions work learners already have.
Misconceptions — surface them, then correct them
Watch for 1 — learners measure from the edge of the ruler, not the zero mark.
Why it forms: on many school rulers the zero mark sits a few millimetres in from the end, and the end of the ruler is the most obvious thing to line up with the edge of the desk. Learners are not being careless; they are using the most visually obvious reference point available.
How to surface it during 'Measure the Real Desk': do not warn the class in advance. Let each group measure and record, then compare two groups' figures on the board. In a class of forty you will almost certainly find a group that reports 119 cm or 121 cm where another reports 120 cm. Ask both groups to bring their metre rulers to the front and lay them along the same desk edge, side by side. The discrepancy becomes visible without you accusing anyone of error.
A quick exit check, with answers
1.A length of 3 m is represented by 6 cm on a drawing. Complete the scale: 1 cm represents ____ m.
Show answer
0.5 m (half a metre)
2.In a scale drawing, every actual length is multiplied by the same ratio.
Show answer
True
3.A desk top is 120 cm by 60 cm. A scale drawing uses the scale 1:20. What are the drawing dimensions?
A. 6 cm by 3 cm
B. 100 cm by 40 cm
C. 5 cm by 4 cm
D. 20 cm by 10 cm
Show answer
A. 6 cm by 3 cm
4.A map of a school compound is drawn to a scale of 1:500. (a) Two gates are 3 cm apart on the map. Find the actual distance in metres. (b) Explain how the scale would change if the same map were enlarged on a photocopier.
Show answer
(a) 3 cm × 500 = 1500 cm = 15 m. (b) Enlarging multiplies every map length by the same factor while real distances stay the same, so the scale changes: if the map is doubled, 1:500 becomes 1:250 (1 cm now represents 2.5 m instead of 5 m).
Outcomes and inquiry questions are quoted from the KICD curriculum design. The lesson plan, notes and exit check are Fuma's draft. Fuma is built from the KICD designs; KICD has not endorsed it.