Week 3
Learning Objectives
By the end of the lesson, Cadet Leaders will be able to:
(a) Identify the two methods used to judge distances
(b) Explain the use of methods to judge distances
(c) Demonstrate the application of these methods in real-life applications
Introduction to Judging Distances
Before a section commander can give a FCO, he has to estimate the distance to the target. This is to ensure that the firepower of the section is fully effective and efficient. In order to provide a just estimation of distances (no more than 20% error), the following pointers are usually taken into consideration.
Factors affecting judging of distances
Pacing
Unit of Measure Method
Halving Method
Factors Affecting Judging of Distances
Visibility - Bright day: target looks nearer; Hazy day: target looks farther
Sun Position - Sun shines into your eyes: target will look farther
Elevation - High ground: target looks nearer and clearer
Target Size - Bigger target: target looks nearer and more defined
Colours - Bright colour: target stands out more and looks nearer
Effect of Terrain - River/depressions in-between: target looks nearer because of the "dead ground" which cannot be seen
Water - Objects across water: give a false image and will look nearer
Pacing
Pacing is done to estimate the distance covered during movement over a distance and different terrains.
Find a flat ground with no obstacles.
Walk forward naturally over a distance of 100m.
Count on every 2nd step you take and record the total number of steps needed to walk 100m.
Repeat Steps 2 and 3. Calculate the average of both attempts.
Find a sloping group with not too steep elevation.
Repeat Steps 2 to 4, this time walking upwards to obtain your upward pacing.
Repeat Step 6, this time walking downwards to obtain your downward pacing.
There are several methods of judging distances, with two of them being the ones you should know.
Unit of Measurement Method
Halving Method
Unit of Measurement Method
This method is similar to using a measuring tape to measure distances, except that it is measured by your eyes. Since most of you are familiar with the length of a football field, (which is approximately 100m), they can be used as a unit of measure. Hence for ranges up to 300 metres, you can judge the distance by estimating the number of football fields between you and the target. However, this method can only be used if the ground between you and the target is visible.
Use of 100m, or your thumb nail to measure distances.
Not a very accurate method; only serves to give a general idea of the distance.
Only accurate to gauge the distance of a human being from yourself
Not accurate for distances more than 300m.
Ask your friend to stand at one end of a park while you stand at the other.
Stretch out your left hand with your thumb pointing upwards.
Adjust the distance between you and your friend until he/she fits the length of your thumb nail. The size of a person at 100m away is equivalent to the length of the thumb nail.
For a person 200m away is approximate to half the length of the thumb nail.
For a person 300m away is approximate to 1/4 the length of the thumb nail.
Halving Method
This method is useful for judging farther distances (> 300m), and can incorporate the use of Unit of Measurement Method as well.
Pick a halfway point between the target and yourself.
Estimate the distance to the halfway mark by using the Unit of Measurement Method.
Double this distance to obtain the estimated distance from the target to yourself.
When using this method, the effect of terrain and weather conditions on target appearance need to be taken into consideration.
Task (25 marks)
Decide on a prominent landmark (building, park, playground, etc) that you can see from your location. Adopt both above-mentioned methods to obtain the projected distance from you and the landmark. Get a buddy to take photo from the side, with you and the landmark captured in the shot. (5 marks)
2. Pen down your reflection on a Word document (Portrait, Arial, font size 12) and share them with your Teacher Officer, along with the photo taken, by email / other online platforms as instructed by your Teacher Officer. (20 marks)
Some references for your reflection: (i) Explain the process of obtaining the projected distance (ii) Share the challenges you have faced and overcome.