The researchers present a simple experimental activity to measure the sound intensity level using an Android-based smartphone to prove the inverse square law and analyze the dependence of the sound intensity to the sound source frequency. The type of this study was quantitative research by conducting level of intensity experiment using a pair of smartphones with one smartphone functioning as the sound source using a tone generator free application (app) and the other smartphone functioning as the detector installed with Physics Toolbox sound meter application to measure the arriving sound intensity level. The smartphone functioning as the sound source was placed at a certain place labeled as the origin point (0.0), while the other smartphone as the detector was placed at various distances on the x-axis. In this study, the frequencies of the tone generator used were 500 Hz, 1000 Hz, and 2000 Hz. Then, the sound intensity level versus distance was analyzed to determine the compatibility between the experimental results using a smartphone and the prevailing theory, namely the inverse square model. The sound intensity level detected by the smartphone from 2,000 Hz resulted in the graph with smaller slope after passing 0.3 meters. The results follow the theorem of which the sound intensity level at the detector depends on the distance between the source and the detector based on the inverse square law. When the frequency of a source was changed (500 Hz, 1000 Hz and 2000), the sound intensity also changed. Higher frequency leads to a larger sound intensity. The experiment can thus be used to assist  high school students and physics undergraduates in understanding the inverse square law of sound or to study environmental noise with a simple and low-cost experiment.

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The use of sensor on smartphones as physics learning media encourages teachers to reconstruct teaching methods. This paper presents the effect on students’ cognitive abilities using an accelerometer and a gyroscope sensor simultaneously in learning circular motion, as well as students’ responses and the effectiveness of sensor media on smartphones used. A pre-experimental research design was used in this study which involved 12 students of XII MIPA at SMA Negeri 1 Pagaden Subang Jawa Barat. They learned circular motion guided by the smartphone sensors-based worksheets and were tested using an essay test for cognitive abilities measurements. Meanwhile, students’ responses and the effectiveness were obtained using a Likert scale questionnaire. The improvement of students’ cognitive abilities was significantly higher than the pretest which was obtained from the N-gain with a final value of 0.41. Worksheets using smartphone sensor media were more effective than conventional learning. In addition, students showed a positive response in which 93.75% of students were interested, 85,42% were motivated to learn the circular motion, and 91.14% of students became easier in understanding physics concepts.

Practicum is an important part of Physics learning that cannot be ignored even in distance learning. Obstacles of practicum facilities faced by students can be overcome by using sensor on smartphones as a measuring tool. In this study, the use of the accelerometer sensor on a smartphone has been carried out to analyze the concept of momentum and impulse through the collision of two toy cars. Two toy cars A and B with smartphones attached have their respective masses of m1 0.31345 kg and m2 0.32116 kg. Car A was idle and car B was moved until it collided car A. In the event of a collision, the accelerometer sensor recorded acceleration data (a) versus time (t). Data (a) versus time (t) was represented in the form of a curve. Next, the data were analyzed. From the graph obtained data t1 =1.237 seconds, when car B started to exert a contact force on car A. The contact time between cars was t = 0.025 seconds. The maximum acceleration experienced by car A during a collision was a = 27.919 m/s2. From the area of the curve (a) vs (t) the impulse value was 0.1217 (N. sec) which is also the value of the change in momentum of car A, with car A's speed after the collision of 0.427 m/s. Thus, the accelerometer sensor on a smartphone can be used to assist students in finding important concepts through practical activities. The use of the accelerometer sensor is expected to help students to facilitate understanding the concepts of momentum and impulse.