TERM – 2^{ND} TERM
WEEK TEN
Class: Senior Secondary School 1
Age: 15 years
Duration: 40 minutes of 5 periods each
Date:
Subject: Geography
Topic: MAP DISTANCE, REDUCTION AND ENLARGEMENT
SPECIFIC OBJECTIVES: At the end of the lesson, pupils should be able to
INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers,
demonstration, videos from source
INSTRUCTIONAL MATERIALS: Videos, loud speaker, textbook, pictures
INSTRUCTIONAL PROCEDURES
PERIOD 12
PRESENTATION 
TEACHER’S ACTIVITY 
STUDENT’S ACTIVITY 
STEP 1 INTRODUCTION 
The teacher explain the meaning of map distance to the students 
Students as a whole, describe the procedures for measuring distances on the map 
STEP 2 EXPLANATION 
Teacher provided a map, measures and calculate distances on it 
Students on their own measures and calculate given distances on a map 
STEP 3 DEMONSTRATIO N 
Teacher show the students how to convert distances on a map to actual ground distance. 
Students on their own convert map distance to actual ground distance. 
STEP 4 NOTE TAKING 
The teacher writes a summarized note on the board

The students copy the note in their books 
NOTE
MAP DISTANCE, REDUCTION AND ENLARGEMENT
Map distance: Map distance refers to the physical distance between two points on a map. It's the measurement of how far apart locations are represented on the map, typically in units like kilometers or miles. There are two types of distance that can be measured on the map.
1. Measurement Of Straight Line Distances
This is the measurement of distance between two places on a straight line. A straight line
This straightline distance between two locations on a map is often called "as the crow flies".
Procedure
Example 1 : Calculate the distance as the crow flies from point A to point B.
The distance between A and B = 7cm
The scale of map = 1:100,000 or 1cm to 1km
Now if 1cm to 1km on the Map,
7cm = 7cm x 100,000/ 100, 000
= 7 km
Therefore, 7cm measured on the map at point A and B is 7km on actual ground.
2. Measurement Of Curve distance
Curve distance include roads, railway, rivers etc. These are distances that are
not straight.
Procedure
1.Use of a pair of divider: To use this method, break the distance into small sections from one bend to another. Use a pair of dividers to measure each short stretch and then determine the distance in centimeters from your ruler. Add up all the sections together and relate it to the scale of the map
2.Use a thread: Stretch a piece of white thread along the route or curve to
be measured and carefully follow all the curves or bends. Mark the end of the
distance on the thread with a pen and transfer to a ruler in order to get the
actual distance on the map between the two places. Relate the distance
obtained to the scale of the map extract to determine the actual distance on the
ground.
Example 2: Imagine the curve on the male below, calculate the distance from the beginning of the curve to the end.
Scale given: 1cm to 2 km
Solution
Using thread to measure the length of the distance and relate it to ruler, you
have 10cm.
Now 10 cm to the scale of the map = 1cm to 2km = 10/1 X 2km=20km
Hence, 10cm measured on the map is 20km on ground.
Conversion from Map Distance to Actual Distance
To convert map distance to actual distance, you need to know the scale of the map. The scale is usually given as a ratio, like 1:50,000. This means that 1 unit on the map corresponds to 50,000 of the same units in reality. Multiply the map distance by the scale to find the actual distance. For example, if the map scale is 1:50,000 and you measured 2 centimeters on the map, the actual distance would be 100,000 centimeters or 1 kilometer.
Example1: If the map distance is 8cm and the scale of the map is 1: 200,000. Calculate the actual distance on ground using either RF or statement of scale.
Solution:
R.F Scale: 1:200, 000. Statement Scale: 1cm to 2km
8cm = 8 X 200,000 / 100,000
8cm = 8 X 2km = 16km
Therefore the actual distance on ground is 16km when the map distance is 8cm
Conversion from Actual Distance to Map Distance.
Example 2: If the ground distance between two places is 20km, what will be the map
distance if the scale of the map is 1cm to 1km?
Solution:
Ground distance = 20km
Map scale = 1cm to 1km
Since 1cm =1km, Map distance = 20cm
EVALUATION: 1. What is map distance.
CLASSWORK: As in evaluation
CONCLUSION: The teacher commends the students positively