The Development of Experimental Sets for Metal Expansion Measurement Using Digital Video-Based Difference Method

The development of the tool has been carried out on a measuring instrument for measuring the length of the metal expansion by a single diffraction method that has been made by the previous researcher. This research based on the problem factors found and the results of experiments that have not been significant. In this study developed the design of the main tool holder form, the temperature measurement with the thermocouple sensor connected to the PC, and the measurement of diffraction pattern distance with digital video analysis techniques using Tracker software. The development of tools and measurements that have been done show very good experimental results. Experimental results on measuring the linear coefficient expansion of aluminum metal obtained values with high accuracy and precision. We got the value coefficient linear expansion of aluminum metal of measurement results is (23.194 ± 0.3102)×10/C with relative error rate 0.84% and relative standard deviation of 1.34%.


INTRODUCTION
The measurement of metal long expansion coefficient is generally carried out through experiments using Musschenbroek tools, which are commonly used in secondary schools.Currently, many other tools and methods have been developed that are used to measure metal expansion coefficient values, one of which is the single slit diffraction method.The experiment tool for measuring the value of the long expansion coefficient of metal by a single slit diffraction method was made by previous researchers Pujayanto (2016, 263-267) and Wulandari (2015).Based on the results of the research that has been carried out, there are still constraint factors that influence the results of research that have not been maximized, including the size of metal materials and design on the main tool, very rapid temperature increases that are not observed due to the limitations of the measuring instruments used, and the use of measuring instruments on measurement's diffraction patterns that occur.Based on these considerations in this study an experimental tool was developed to measure metal expansion coefficient values through a single slit diffraction method with data retrieval using digital video recording.Accuracy of results from measurements using the tools developed is done by comparing the reference and precision calculated by analysis of standard deviations from repeated measurements.

RESEARCH METHODOLOGY
This research went through several stages, starting from the design, manufacture and testing of tools.The design and manufacture of tools were carried out in the workshop of the Department of Physics, Institut Teknologi Bandung.Tool testing was carried out in the Basic Physics Laboratory Basic Science Center A building, Institut Teknologi Bandung.All stages of this research are carried out in the period January -June 2018.
In the concept of long expansion, a metal rod when heated will expand to experience a long increase.The length increment experienced by each metal varies depending on the value of the long expansion coefficient of the metal (Walker 2014).Diffraction refers to various phenomena that occur when a wave passes through a narrow barrier or gap so the wave will be turned over and then the light coming out of the gap will create a pattern on the screen.The link between the concept of length increment and diffraction is the length increment experienced by the metal as a narrow gap in the diffraction process of light that hits the narrow gap.
Calculations are carried out using a device that allows measurement of changes in the width of a single gap that increases with the occurrence of thermal expansion of the length of the metal.The laser beam is used to obtain a single slit diffraction pattern.The increase in the gap width that is proportional to the linear expansion of metal length can be measured by analyzing the diffraction pattern formed then the metal long expansion coefficient can be calculated.Video analysis of diffraction pattern was carried out using Tracker software.Tracker is a software that can analyze and model motion and optical phenomena, not paid and developed by Open Source Physics (OSP) using a Java framework (Wee & Lee 2011).
Taking diffraction pattern distance data using video recording using a camera that produces digital video are then analyzed with Tracker software.Data retrieval of the temperature increase is used thermocouple temperature sensor connected to the PC through Logger Pro software to overcome temperature changes that occur quickly.Digital image processing is carried out through stages namely image acquisition, image digitization, image quality improvement, and graph plotting (Gonzales & Woods 2001). Linear

Development of Experiment Equipment
Obstacle factors that emerged in the experiment to measure metal length expansion coefficients in the previous study were presented in TABLE 1 which was included with the cause analysis and development carried out.

Constraints Factors
Analyze Factors Tool Development a. The main tool is not sturdy which causes the device not to be in an upright or steady position.
The size of the metal strip used is too thin, so that when it is formed not perpendicular and must hold the weight of the wooden support from the gap made from a pair of razors it is not strong because it is too thin to cause the position of the main tool to be unstable.
The size of the metal strip used was replaced by a thicker size, which was originally 0.5 mm in size and changed to 1.0 mm in size and the metal width was made between 20 mm.

b. Uneven expansion on both sides
The holder of the main tool is designed on one side by clamping on the top of the side which causes when there is an expansion only in one direction, and the position or position of the holder of the tool is susceptible to expansion direction, which is initially designed only in one direction but can expand at the other side is not balanced.
Change the design of the main tool holder and its position.The tool holder who previously used the clamp on the top of one side of the metal was replaced by using a screw mounted on the bottom of the metal which had been given a hole in the middle by drilling.So this guarantees expansion will be balanced on both sides of the metal.
c.The temperature rise is too fast so that it cannot be observed on the scale of the increase in 1 0 C.
The accuracy of the analog temperature gauges used and the limitations of the observer's vision as a human.When the heattransfer media (water) is expected to increase the temperature will be faster.This will make observing temperature increase data inaccurate.
It is replacing a temperature gauge with a digital temperature measuring device that is using a thermocouple sensor that is connected directly to the PC via a vernier interface as a connection.

Constraints Factors
Analyze Factors Tool Development d. Inaccuracy in measuring the width of the diffraction pattern on the screen A rapid rise in temperature accompanied by a widening of the gap causes a change in the diffraction pattern on the screen will also occur quickly while measuring the width of the diffraction pattern using an analog length measuring instruments such as a ruler or millimeter block.
The camera is used to record video images from diffraction patterns that occur then the digital video image is analyzed using Tracker software.
e.There is a diffraction pattern that is not static (moving) on the screen when the state of the heat transfer medium (water) reaches the boiling point.

When
observations are carried out in a long time, there will be a phase change in the heat-transfer media in this case the water will evaporate and change the phase to steam, this water vapor that affects the path of light around the main tool or metal.So that the diffraction pattern on the screen will shake or move.
Make the water container cover design designed above follow the pattern of the main tool.
The size of the metal and the design of the main tool of the researcher were previously seen in FIGURE 2a and FIGURE 2b

Tool Test Results
The results of testing of experimental devices that have been developed to provide several physical parameters that can be measured, namely temperature (T), time (t) and distance of the first dark diffraction pattern (y).FIGURE 4a shows a graph of the relationship of the first dark order distance (y) to temperature (T) and FIGURE 4b graph of the relationship of the first dark order distance (y) to time (t).FIGURE 3a shows a graph of the relationship between the distance of the first dark diffraction pattern and the increase in temperature.When the temperature increases, the smaller the diffraction pattern distance, which means the diffraction pattern distance that occurs on the screen narrows.Temperature rise often occurs with increasing time which results in a smaller change in the distance of the diffraction pattern, as seen in FIGURE 3b.This shows that the diffraction gap widens due to expansion occurring in the metal.From the results of the experiment, the relationship between the  The graph in FIGURE 4 is obtained from the results of linear regression analysis of the relationship between 1 / y (y = first dark order distance) to T (temperature).This is also consistent with the results of Bharmanee's research (2008) and Fakhrudin(2006).The experimental data shows that the higher the temperature of the diffraction gap, the wider and the distance the diffraction pattern narrows.So it can be concluded that the temperature rise is inversely proportional to the distance of the diffraction pattern.From the graph obtained a gradient value which is then used to calculate the value of the aluminum metal expansion coefficient.
Experimental data from the analysis of measurements of aluminum metal long expansion coefficients are shown in TABLE 2. The analysis carried out includes an analysis of accuracy by comparing the reference data, and precision analysis carried out by calculating the standard deviation and the relative standard deviation of repeated measurements.2,186 × 10 -7 0,95% x = (23,100 ± 0,2186)×10 -6 / 0 C with relative error 0,43% TABLE 2 describes the closeness or similarity between the experimental values obtained with reference values that are used as a reference.Accuracy is the level of ability of the tool to provide measuring results that are close to the actual value.Comparisons are made assuming errors (the smaller the error, the greater the accuracy).The relatively small error value indicates that the measurement has a high level of accuracy, accuracy, and accuracy indicating that the measuring instrument used has a high degree of accuracy.
The measurement value shows that the data is quite consistent for each type of metal, whether aluminum, iron or copper, indicating that the measurement has a high level of consistency as evidenced by the relatively small standard deviation and standard deviation.Standard deviation is a e-Jurnal: http://doi.org/10.21009/1 benchmark that shows the level of precision in measurement, the smaller the standard deviation value, the more the level of precision.

CONCLUSIONS
The development of experimental equipment for measuring the length of metal expansion coefficients with digital video-based diffraction method in the form of development of the design of the main tool holder, temperature measurement with thermocouple sensors connected to the PC, and distance measurement of diffraction patterns with digital video analysis techniques using Tracker software yielded results positive in the form of a high degree of accuracy and precision.The aluminum expansion coefficient value of the experimental results was obtained (23,100 ± 0,2186) × 10 -6 / 0 C with a relative error average of 0.43% and a relative standard deviation of 0.95%.
The experimental tool for measuring the length of the metal expansion coefficient developed is expected to contribute to the development of physical practicum materials regarding expansion and diffraction at the high school level.The development of further research is recommended to measure long expansion coefficients for other metals.

FIGURE 2 .
FIGURE 2. (a) Design of the main research tools before, (b) Design of the main tool after being developed, (c) Mercury thermometer used by previous researchers, (d) Thermocouple sensors used to measure temperature, (e) Millimeters of blocks used to measure distance of diffraction patterns in previous researchers, (f) Tracker software to analyze the distance of diffraction patterns.

FIGURE 4 .
FIGURE 4. (a) Graph y (first dark order distance) to T (temperature), (b) Graph y (distance of the first dark order) to t (time) p-ISSN: 2461-0933 | e-ISSN: 2461-1433 150 e-Jurnal: http://doi.org/10.21009/1temperature rise of each 1 0 C and 1/y (y = the distance of the first dark diffraction pattern to the center light) is shown in FIGURE 4.

FIGURE 4 .
FIGURE 4. Graph 1 / y (y = first dark order distance) with respect to T (temperature)

TABLE 1 .
Factor's constraints, analysis of causes, and development of experimental tools.

TABLE 2 .
Results of data analysis of Aluminum metal long expansion coefficient values