Using Tracker as a Pedagogical Tool for Understanding the Kinematics of an Object Rolling Down on an Inclined Plane Menurseto Mawaddah1, Wiwin Sriwulan2, and Eka Cahya Prima1,a) 1
International Program on Science Education, Universitas Pendidikan Indonesia, Jl. Dr. Setiabudi no 229, Bandung 40154, Indonesia 2 SMP Laboratorium Percontohan, Universitas Pendidikan Indonesia, Jl. Dr. Setiabudi no 229, Bandung 40154, Indonesia a)
Corresponding author:
[email protected]
Abstract. Nowadays, a video analyzer technology capturing a real-world physics experiment will encourage students to learn science actively. In a case of studying a rolling object on an inclined plane, teachers commonly use a ticker timer in order to explain the kinematics of its object motion. The aim of this study is to introduce tracker analyses as a modern pedagogical tool for understanding the kinematics of a rolling object on an inclined plane implemented at a secondary school in Bandung. The result shows the experiment procedures to implement its experiment using tracker, the graphs and datum of students’ experiment and the effect of inclined plane angles towards kinematics aspects of object motions. In accordance with students’ questionnaires, 80% students were satisfied in conducting experiment using tracker video analyzer. The research implied that this design would be better to improve students’ science process skills using an inquiry approach in detail.
INTRODUCTION Tracker is a video analysis and modeling tool built on the Open Source Physics (OSP) Java framework [1]. The ideal of science instruction should be led to hands on activity to give the best learning experience for the student as well as to increase the students’ science process skills. In this modern era, there are still many schools, which do not have enough facilities for science instruction provided by the government. Consequently, teachers have difficultness in presenting real experiments for the student. In a case of studying a rolling object on an inclined plane, teachers commonly use a ticker timer in order to explain the kinematics of its object motion. Some schools do not have enough media to supports this experiment. Therefore, the solution can be proposed by capturing this experiment using video analyzed by Tracker video analyzer. The video can effectively focus on introducing computational physics models to lower division students. Because the video captures the real phenomenon by direct visual inspection, this video enables students to explore some different model equations, parameters and algorithms in a real-world context [2]. This physics teaching approach makes studying natural sciences to be more interesting for students by implementing Tracker programs [3]. The aim of this study is to introduce tracker analyses as a modern pedagogical tool for understanding the kinematics of a rolling object on an inclined plane implemented at a secondary school in Bandung.
RESEARCH METHODS This research consists of three steps of experiment. Firstly, a teacher prepares the rolling object experiment with four kinds of batteries, five kinds of incline planes angles. Secondly, a teacher analyzes the video using tracker and compared it to the equation of rolling object. Thirdly, a teacher implements the experiment to the first grade of secondary student.
Experiment Preparation of Rolling Object The materials we used for rolling object are four kinds of batteries with different mass and diameters. The length and diameter of batteries are measured by a Vernier caliper with 13 cm main scale and 0.05 mm Vernier scale. The battery mass is measured using an Ohaus digital balance model CL 201T with 200 0.1gram capacity. Table 1 shows the result of measurement. TABLE 1. The data of battery measurements. Mass (gram) Diameter (cm)
Name of battery
Panasonic AAA ABC AA Energizer AA Panasonic Prima D
9.350 17.95 22.35 97.35
0.05 0.05 0.05 0.05
1.0225 1.3725 1.4175 3.2425
0.0025 0.0025 0.0025 0.0025
Length (cm)
4.2225 4.7075 4.8575 5.7475
0.0025 0.0025 0.0025 0.0025
The materials used for setting the plane are obtained from KIT MEKANIKA PMS 500 made by Pudak Scientific™ (precision plane with length of plane is 50 cm and storey box). The plane is set in four different heights. The height of set I (SI) is 1.5625 cm; the height of set II (SII) is 2.5025 cm; the height of set III (SIII) is 3.5025 cm; the height of set IV (SIV) is 4.5025 cm; the height of set V (SV) is 5.5325 cm.
Concept of Rolling Object The calculations are conducted in order to compare real situation with mathematical description as given in Eq. (1) through Eq. (7). Figure 1 shows the force acting on the battery.
FIGURE 1. The illustration of incline plane using torque principle
f=k.m.a
(1) (2)
Next, we put f into the Second Newton’s Law of translation motion. (3) (4) (5) (6) (7)
Implementation to Students in the Classroom The experiment will be presented to 7th grade students of a secondary school in Bandung. A class consisting of 25 students will be interviewed after implementing the experiment.
RESULTS AND DISCUSSION After analyzing the video using Tracker, the data are obtained as tabulated in Table 2. The table contents consist of SI Graph which has 1.5625 cm in height, SII Graph which has 2.5025 cm in height, SIII Graph which has 3.5025 cm in height, SIV Graph which has 4.5025 cm in height, SV Graph which has 5.5325 cm in height. Figure 1 respectively shows the graph of position vs. time, graph of velocity vs. time, and graph acceleration vs. time.
2.50
0.00
FIGURE 2. These figures represent: a. the graph of position vs. time, b. graph of velocity vs. time, c. acceleration vs. time with four different mass
Figure 2 proves that battery mass do not affect these graph patterns. Graph of position vs. time and velocity vs. time show good trend line, but the graph of acceleration vs. time tend to show data randomly. Figure 3 shows the graph of SI-SV comparison of position vs. time, velocity vs. time, and acceleration vs. time.
0.00 0.00
2.50 Time (s)
FIGURE 3. These SI-SV comparison graphs show (a) position vs. time, (b) velocity vs. time, (c) acceleration vs. time analyzed from a battery with 9.350 g mass. Blue color represents SI, red color represents SII, grey color represents SIII, yellow color represents SIV, and purple color represents SV.
By analyzing the data and trend line of graphs, it can be analyzed that the more plane height, the faster battery rolling down the plane. The relationship between acceleration and plane angle represented as sin θ is tabulated in Table 2.
TABLE 2. The data of acceleration vs. sin θ
Set SI SII SIII SIV SV
Height (cm) 1.5625 2.5025 3.5025 4.5025 5.5325
Distance (cm) 50.5 50.5 50.5 50.5 50.5
Sin(θ) 0.03 0.05 0.07 0.09 0.11
mass 1 17.89 28.68 44.19 52.73 64.62
Acceleration (cm.s-2) mass 2 mass 3 16.35 15.63 30.00 25.99 38.47 82.48 49.28 52.16 65.66 66.76
mass 4 18.41 29.62 46.02 52.36 71.79
FIGURE 4. Graph of Acceleration vs. Sin θ
Figure 4 shows the graph of acceleration vs. sin θ. The data can be examined that the more sine θ, the more acceleration rate by neglecting the friction. Therefore, the velocity and acceleration depend on the plane height and the degree of plane.
Implementation The experiment implementation in the class has been successfully conducted. All students involve to do this experiment. A teacher firstly demonstrated the rolling object with different angle followed by showing the tracker video analyzer to the student. At the introduction stage, students feel confuse because the experiment is not familiar to them, so the teacher explains the experiment activity clearly. Afterward, students enthusiastically run this experiment in the class. The result can be proven by the interview that 80% students are satisfied doing this experiment. According to the teachers conducting the experiment and observers including other teachers and observers participating the observation in the class, this aplication is very helpful. The application can be used as one of alternative media for describing a real time based-experiment. The activity suggests that the student should be directly involved on some activities including recording the video, analyzing the Tracker, interpreting the data, and presenting the experiment result that can be implemented in the higher school level. Moreover, the research also implied that this design would be better to improve students’ science process skills using an inquiry approach in detail.
CONCLUSIONS The Tracker video analyzer has been implemented successfully at a secondary school to understand the kinematic concept of rolling object. By using the tracker, the experiment is easy to be conducted. The experiment result shows the graphs of position, velocity, and acceleration as functions of time. 80% students are satisfied in conducting experiment using tracker video analyzer. Hence, the application is good for pedagogical tools helping students’ secondary school to understand the kinematics concept of an object rolling down on incline plane.
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L.K. Wee, C. Chew, G.H. Goh, S. Tan, and T.L. Lee, Physics Education 47, 448 (2012).
2. 3.
D. Brown, "Video modeling: combining dynamic model simulations with traditional video analysis." in American Association of Physics Teachers (AAPT) Summer Meeting-2008. J. Bryan, Contemporary Issues in Technology and Teacher Education 4, 284-298 (2004).
