EXPERIMENT NO. 4 MEASUREMENT OF AREA NAME
1. Prado, Mon Patrick 2. Publico, Jerome R. 3. Rinon, Daniel S.A 4. Rivera, Kristian Asterio R.
SECTION GROUP #
57045 5
I.
DATE PERFORMED: August 30, 2017 DATE SUBMITTED: September, 2017 INSTRUCTOR:
SCORE:
Engr. Lester Alfred M. Olasiman
OBJECTIVE:
The activity aims to demonstrate the procedure in measuring the area of regular and irregular shapes and sizes using planimeter. II.
LEARNING OUTCOME (LO):
The students shall be able to: 1. Measure the area of regular and irregular shape and size using digital and analog planimeter. 2. Interpret data and relate result to governing scientific principle. 3. Develop professional professional work ethics, including precision, neatness, neatness, safety and ability to follow instruction III.
DISCUSSION:
Planimeters are used to measure areas on maps of any kind and scale, as well as plans, blueprints or any scale drawing or plan. They are often used by surveyors, foresters, geologists, geographers, geographers, engineers and architects. Mechanical (non-digital) planimeters feature a pole arm, tracer arm, tracer magnifier, recording dial, and Vernier measuring wheel. Some models have adjustable length pole and tracer arms, while others are fixed length. All have a reset which returns the measuring dial and Vernier scale to zero before the next use. Digital planimeters are computerized. They give a direct reading of the area traced as square inches or centimeters, with some reading directly in any unit of area including acres, square meters, square kilometers, etc. The most advanced units will also store data for downloading into a personal computer. Most digital planimeters have various memory functions which enable you to add areas, accumulate measurements measurements and average multiple measurements. measurements. Digital planimeters are available with pole arms or rollers.
To use a mechanical planimeter, a "constant" is first determined by choosing the shortest possible arm length which will cover the area to measure, and tracing the boundary of a known area Once the known area is traced, you can see how many revolutions the dial scale indicates. The known area divided by the dial reading equals the constant. Once the constant is determined, the measuring dial is reset and the boundary is traced by moving the magnifier over the boundary in a clockwise direction. The reading on the dial is multiplied by the constant to give the desired area of the plot. Digital planimeters require initial settings for units and scale. There is no need to determine a constant when using any digital planimeter.
Figure 1. L30 MODEL PLANIMETER
IV.
MATERIALS AND EQUIPMENT:
1 set Mechanical Polar Planimeter 5 different figures
V.
PROCEDURE:
Experiment Procedure: 1. Before any measurements are attempted, make sure that the measuring surface is suitable. It should not be very glossy, (photographs) too rough, mutilated, torn or patched up with adhesive tape. If the measuring surface is not quite suitable, cover it with a transparent sheet of tracing paper to minimize the problem. Make sure that the measuring table is reasonably flat and that both pole weight and planimeter body operate at the same elevation. 2. Assemble your your instrument instrument as shown on figure 2. and and select select the tracer arm arm length most most suitable for your application.
Figure 2 3. Place the tracer point TP of your planimeter in the approximate center of the area to be measured. Position the pole weight in such a manner, that the pole arm P and the tracer arm T form a 900 angle (approx.) as shown in figure 2. 4. Make a quick cursory tracing around the area to t o be measured to make sure that the measuring wheel does not run over paper edges and that the area can be covered in one single continuous operation. 5. Select a starting point S somewhere on the area periphery and move the tracer point TP over it as shown in figure 3. 6. Set the measuring mechanism to zero or take an initial reading. 7. While keeping the tracer point TP precisely over the peripheral line, move the tracer around the area in a clockwise direction until the circuit is closed and the starting point S is reached again. Important: While measuring, keep the instrument level on the measuring surface to avoid a lift off the measuring wheel. 8. Read the result off the measuring mechanism. mechanism.
Figure 3 9. If the counter was cleared prior to the measuring process, the result "N" can readily be used to obtain the actual area measurement. 10. If you took an initial readout prior to the measurement, it must be subtracted from the final readout to obtain "N". 11. For 1:1 measurements expressed in inch2 or cm2, multiply the result "N" by the "u" value given for your model 10 or 20 or, if your instrument is a model 30, by the "u" value for the arm extension used. 12. For scale measurements to be expressed in ft2, acres, mile 2, m2, ha, km2, multiply "N" by CA. (= Scale Area Constant)
VI.
DATA AND RESULTS:
Figure
Dial
Major Wheel
Minor Wheel
Vernier
Result
Area in2
% Error
1. Square
0
4
2
8
0428
4.28
7%
2.Triangle
0
2
0
2
0202
2.02
1%
3.Rectangle
1
0
3
8
1038
10.38
3.8%
4.Triangle(BIG)
0
8
1
0
0810
8.1
1.23%
5.Trapezoid
0
5
6
6
0566
5.66
5.67%
VII.
COMPUTATIONS: Figure
Computed
Square
A = S2 = (2)2 A = 4 in2
Triangle
A = 1⁄2 ℎ A = 2 in2
Triangle(BIG)
A = 1⁄2 ℎ A = 8 in2
Rectangle
A = L x W = (5x2) A = 10 in2
Trapezoid
A = 1⁄2 ( + )ℎ A = 6 in2
Measured A = N x u A = 0428 x 0.01 A = 4.28 in2 A = N x u A = 0202 x 0.01 A = 2.02 in2 A = N x u A = 0810 x 0.01 A = 8.1in2 A = N x u A = 1038 x 0.01 A = 10.38 in2 A = N x u A = 0566 x 0.01 A = 5.66 in2
% Error 4−4.8 100= 7% 4 −. 100= 1% 8−8. 100= 1.25% 8 −.38 100= 3.8% 6−5.66 100= 5.67]3.8% 6
VIII.
DISCUSSION OF RESULTS:
While the level of exactness in comes about feasible in the different operations of estimation with the Planimeter as depicted in the past parts has been given in the talk of the utilization of the Planimeter in those portrayals, it will be of enthusiasm for determination and give a clearer comprehension of the general subject of the precision of Planimeter estimation to give the consequences of the investigations which have been made at different circumstances to decide the relative and real level of exactness which might be unquestionably unquestionably expected in the different types of operation. Not exclusively is an information of the level of precision achievable achievable in these operations of the best conceivable incentive incentive as outfitted proof of the dependence which might be set in all aftereffects of estimations along these lines got, yet they fill the additional need of demonstrating the practically boundless estimation of the guide these instruments are fit for rendering in each type of Engineering work and giving them the high place in the rundown of the Engineer mechanical aides for which that exactness and versatility so famously fits them. In this experiment a planimeter is utilized to quantify the region of a regular shape, it is finished by simply following the outer line of the area, starting from the center and to an edge which will serve as a starting point.
IX.
CONCLUSION AND RECOMMENDATION:
The precision of our examinations relies upon two components components one is the natural factor and the other is human error. Environmental Environmental Work
The working region can influence the precision of the trial esteem. On the off chance that the surface is not leveled the roller in the planimeter. Additionally if the testing subject is not in great conditions the outcome will not be right.
Human Error
A few people get preferred outcomes over others. A decent eye, an enduring hand and tolerance when following the blueprint are most critical for good outcomes. Great light and a happy with working position likewise assume a conclusive part.
Recommendation
To have precise results in conducting the experiment we should consider the environment and the human error that will occur in the experiment to lessen the discrepancy. Also we should consider the condition of the test subject to have a proper evaluation in conducting the experiment.
X.
RUBRICK:
EXCEEDS EXPECTATION
MEETS EXPECTATION
BELOW EXPECTATION
NOT ACCEPTABLE
4
3
2
1
CRITERIA
Laboratory Skills (30 %)
Data and Calculation (20 %)
Analysis
(20 %)
Demonstrate needed skills to finish the task, able to set – up the materials with without supervision and always follow safety guidelines during laboratory performance.
Occasionally Partially demonstrate demonstrate needed skills to needed skills to finish the task, able finish the task and to set – up the able to set – up materials with the materials with minimum supervision, supervision, partially follows occasionally safety guidelines follows safety during laboratory guidelines during performance. laboratory performance. Professional Accurate Accurate looking and representation of representation of accurate the data in tables the data in written representation of and/or graphs. form, but no the data in tables Graphs and tables graphs or tables and/or graphs. are labeled and are presented. Graphs and tables titled. are labeled and Some calculations titled. Some calculations are shown and the are shown and the results labeled All calculations results are correct appropriately. are shown and the and labeled results are correct appropriately and labeled appropriately. The relationship The relationship The relationship between the between the between the variables is variables is variables is discussed and discussed and discussed but no trends/patterns trends/patterns patterns, trends or logically analyzed. logically analyzed. predictions are Predictions are made based on made about what the data. might happen if part of the lab
Do not demonstrate the needed skills to finish the task, do not able to set – up the materials and do not follow safety guidelines during laboratory performance.
Data are not shown OR are inaccurate. No calculations are shown OR results are inaccurate or mislabeled.
The relationship between the variables is not discussed.
Conclusion (30 %)
were changed or how the experimental design could be changed. Conclusion includes whether the findings supported the hypothesis, possible sources of error, and what was learned from the experiment.
Conclusion includes whether the findings supported the hypothesis and what was learned from the experiment.
SCORE
INSTRUCTOR COMMENT AND SUGGESTION:
Conclusion includes what was learned from the experiment.
No conclusion was included in the report OR shows little effort and reflection.
