The Effectiveness of Android-assisted Optical Devices Learning to Improve Students ’ Conceptual Understanding

This research aims to find the effectiveness of Android-assisted optical devices learning to improve students’ conceptual understanding. This research was a quasi-experimental research with a pretest-posttest design. This research involved 60 second year high school students in West Kutai Regency, East Kalimantan. The instrument for the data collection was comprehension questions about conceptual understanding on optical devices tested through pretest and posttest. The conceptual understanding data was analyzed using anava mix design. The result shows that learning optical devices using an android application is more effective in improving students’ conceptual understanding compared to conventional learning which is not using an android application.


INTRODUCTION
Smartphone with an android operating system is one of the fastgrowing technology devices recently.
Stat Counter for Indonesia area released statistical data on September 2018 which shows that from the total users of smartphone and tablet operating system, 91.95% of them are using android as the operating system.The estimation and statistical data show that Indonesia is one of the countries with the largest active Android smartphone users in the world.
Today, android smartphone is an electronic device that most high school students own.
As the sophisticated device, smartphones can help to analyze the physics phenomena (Kuhn & Vogt, 2013).In terms of learning media, smartphones can be interesting learning media that help students to overcome conceptual difficulties and learn more enthusiastically (Vieyra & Vieyra, 2014;Gonzales, 2014;Fatimah & Mufti, 2014).
In education especially the learning process, technology has a very important role (Zatarain et al., 2016;Stantchev et al., 2014).The use of smartphone applications helps students to improve their skills and build a coherent mental framework (Yang, 2012).Android applications can improve interpretation skills, , and argumentative students in physics learning (Yadianur & Supahar, 2017;Liliarti & Kuswanto, 2018).The use of learning applications with a blend of virtual-based technology can significantly improve student understanding (Wang, 2015;Chiu et al., 2014;Blikstein et al., 2012).Therefore, the use of android applications for physics learning will help students to understand Physics better.Notes:   The history of magnifying glass invention, formation of shadow objects on a magnifying glass, magnification of magnifying glass when the eyes are accommodated and not accommodating

Camera
The history of camera invention, formation of shadow objects on a camera, roles and functions of camera parts Microscope The history of the microscope, microscope parts, formation of shadow on a microscope and mathematical equations related to magnification of a microscope.

Telescope
The history of telescope invention, star telescopes, earth telescopes, stage telescopes, reflective telescopes and mathematical equations related to telescopes magnification  Even though the treatment given to both groups shows positive and effective results to improve students' conceptual understanding, learning with android is much more effective than ordinary conventional learning.This result can be seen in Figure 4.  shows that the experimental group has higher posttest score than the control group.Multivariate tests result can be seen in Table 5.The use of android application in the learning process is proven to be more effective in improving students' conceptual understanding.However, there are several things that should be revised when using the android application in the learning process.In the learning process, it was found that there were some students who actually opened a game application in their android smartphone and they did not really study.

Periscope
Therefore, students should be supervised when using their android smartphone so that the learning process can be more effective.

CONCLUSION
Optical devices learning by using the android application is more effective in improving students' conceptual understanding compared to the learning without the android application.Students with the android application can improve their conceptual understanding, 83.7%.
While the conventional learning is 49.9%.This result shows that learning by using the android application is more effective in improving students' conceptual understanding of optical devices materials.

SUGGESTION
The similar researches need to be conducted for other physics materials in order to improve students' conceptual understanding.When using the android application in the learning process, students should be supervised so that they will not open other android applications which will disrupt the learning process.

Figure 1 .
Figure 1.Main Menu App Each menu button is connected to other pages containing optical devices materials.The details of optical is compiled using Microsoft Publisher and saved as an image file in jpeg format.The image is then inserted into android studio 3.0.The java command is used to call the image, so when the button in the main menu is pressed, the page or activity containing optics materials will be called and displayed.The next page (activity) will be called when the button is pressed.The materials presented contain facts, concept, image and mathematical equations that will help students in learning optics.The display of materials page can be seen in the Figure 2. In order to help students in learning optics, the android application developed also includes several simulations related to optical devices.The display of camera simulation page can be seen in the Figure 3.The camera simulation illustrates the change in the image taken by the camera when the lens focal distance changes.This simulation is an adaptation of the focus of the camera's interactive simulation.There are three main parts of this simulation.Part (1) in the form of line drawing is an image of a lens change that changes the focus distance.Part (2) in which the object is two threes and a forest.Part (3) consists of a buttonand a button + which are the lens focus converter.In this simulation, when the button + and the buttonare pressed, then the focus point of the camera lens will change.During the learning process, students form the experimental group will be given problems related to optical devices.To answer those problems, students read the material and run the simulation in the android application.Some students will answer the problems and the other will present in front.Android application used is one of the medium to facilitate students to find information and understand the concept of optical devices.For the control class, students will use hand out containing optical devices materials.The hand out will help students find the information related to optical devices.The data on students' conceptual understanding was obtained using written test in the form of description questions as much as 7 items.The detail of indicators in the questions can be shown on

Figure
Figure 4. Graph of Differences in Conceptual Understanding ImprovementOn the figure 4 about graph of the differences of conceptual understanding improvement, time 1 (pretest) shows that initial point of both graphs is nearly close.This shows that the initial pretest scores have almost the same score.In addition, students in the experimental or control group have almost the same level of understanding (Homogeneous).In time 2 (posttest), it