Development of science chess media based on Higher Order Thinking Skill (HOTS) to increase the understanding of science concept in students

This research generally aims to develop science chess media based on Higher Order Thinking Skills that valid for students. The specific objectives of this research are (1) developing science chess media based on higher order thinking skills, (2) knowing the feasibility of developed learning media, (3) knowing student learning outcomes after participating in learning using science chess media based on Higher Order Thinking Skills, (4) determine the response of students after learning. The application of science chess in learning uses one group pretest-posttest design. The research method used is development research by following 4 phases of Plomp. There is problem, analysis, design & develop prototype, and evaluation and then continued with the application using the one group pretest-posttest design. Based on research, it can be obtained: 1) the feasibility of science chess media based HOTS in the aspects of content feasibility, presentation, language according to BSNP (National Education Standards Board), and contextual assessment are in the category of decent to use, 2) the increase of student’s understanding on scientific concepts using science chess media based HOTS is 62.5, and 3) students gave a positive response to the science chess media based HOTS.


Introduction
Improving the results of learning science, teachers are required to be more professional in preparing learning tools to suit the conditions and circumstances of the student environment, so that the subject is easily understood by students. Based on the pretest results before learning, students' understanding of science concepts obtained an average value of only 65.7. Besides that, the students' ability in solving everyday problems involving science concepts is obtained 50.9 in the low category. The minimum score so they can past this subject should be 75. The low average score of these students shows that their ability to understand the concept of science is still low. This is due to several factors including the models, method, media, and the teacher's skills in learning. Learning math requires a creative, innovative and fun through students' engagement that is facilitated by the teacher in order that the students to find and solve problems [1]. This is in line with the students' belief of mathematical that the three main factors, belief in in their ability, the mathematical discipline and towards mathematical teaching and learning [2].
The media has a very important contribution to the learning process. Science chess media is a media developed by researchers. In terms of appearance, this media has several advantages such as the appearance of images in three dimensions (3D) as well as chess and dip boards made to resemble various symbols in science. While in terms of substance, the strengths of science chess contain science concepts that help students carry out the process of analysis, synthesis, and creation to solve daily problems. This media is expected to help the process of learning science in the classroom, especially in the delivery of material that the process cannot be seen directly by students. It is stated that mathematical connection ability is the ability to link or connect the internal and external relations of mathematics that involves concepts, connection with other discipline and connection with everyday life [3].
Entering the 21st century many things have changed in all aspects of life, including education. The acceleration of the development of science and technology, communication systems, and unlimited internet access became one of the characteristics of the beginning of this century. This also changes the educational paradigm. Schools are required to change competencies. The ability to think critically, solve problems, and collaborate becomes important competencies in entering 21st century life. However, the reality on the ground is often not in line with what we expect. Based on observations of students at STKIP Bina Insan Mandiri who were asked to solve problems that required 21st century competence, only 4 out of 10 students were able to solve them. This shows that their ability to solve problems is still low. Ariyati also mentioned that there are still many first-year students who cannot solve problems in daily life [4]. Therefore, we need a skill called higher order thinking skill (HOTS). HOTS is a cognitive operation that is needed in the thinking processes that occur in short-term memory. In relation between HOTS and mathematics, the difficulty of mathematics has become a stigma in the society hence it is vigorous to alter it though the implementation of HOTS [5], They added that students' attention in interest of mathematics can be attracted by using HOTS.
Based on the above reasons, researchers chose to develop science chess media based on HOTS to help students understand scientific concepts. The objectives of this study include: (1) developing science chess media based on higher order thinking skills have valid; (2) knowing the feasibility of developed learning media; (3) improve students' understanding of science concepts using science chess media; (4) knowing the students' responses after learning.

Research method
Design of this research uses One Group Pretest-Posttest Design [6]. The first step is to take measurements as a preliminary test, then subject to treatment within a certain period, then do the final test which can be described as follows: The validation data were analysed descriptively qualitatively. In this study passing grade (acceptance limit) is the average score ( ) of the results of the validator's evaluation then the level of validity of the device developed by matching the learning instrument criteria according to Gronlund in [7] is as follows. The reliability of the questions was analyzed descriptively qualitatively using the Alpha formula, namely: Note: n = number of items, Σ 2 = number of variance scores for each item and 2 = average score variance. questions are very easy The sensitivity of the questions in this study were analyzed descriptively qualitatively using the formula = Σ − Σ ( − ) Note: S = index sensitivity problem, N = number of students, ƩS ses = number of subject scores after learning, ƩS seb = number of subject scores before learning, S max = maximum scores achieved by students, and S min = minimum scores achieved by students.
Price sensitivity starts from 0 -1. Price 0 is not sensitive while 1 is very sensitive. For analysis of understanding of science concepts in students using paired t test. Paired t test was used to determine the understanding of science concepts in students. This test is used to determine the difference between two data groups that are normally distributed. The t-paired test formula is: Note: 1 = average sample before treatment, 2 = average sample after treatment, S1 = standard deviation before treatment, S2 = standard deviation after treatment, n1 = number of samples before treatment and n2 = number of samples after treatment. Analysis of Student Responses. Student response questionnaire is used to find out students' opinions on the media developed, how to use them, and their benefits in helping students understand concepts. Student responses were analyzed descriptively quantitatively using the formula: Note: P = percentage, ∑ R = number of responses and ∑N = total number of responses   Based on table 7 it can be seen that during pretest student grades very low. Then after learning by using science chess media and given a test post, their scores have increased. The increase occurred by 62.5 or around 77%. So it can be concluded that there are significant differences in learning outcomes between before and after learning. This indicates that science chess media based on higher order thinking skills (HOTS) developed by researchers can improve students' understanding of photosynthesis material

Student Responses to HOTS-Based Science Media Chess
From the data in table 8, it can be seen that students have responded positively to the chess learning media developed. The use of media in learning process plays an important role especially the learning process that applies HOTS. Implementation of higher order thinking skill of students will enhance students' skill in problem solving strategies [8]. Using media that facilitate HOTS in the learning process was carried out to get a maximal learning achievement. In line with this, there are studies proved that social group activities like group projects or other collective problem solving enables HOTS to be established [9]. The use of media science chess proved to be helpful for the students. This media encouraged the students to be engaged in the learning. Sumarmo [10] stated that interaction among students with their peers or teachers can be optimized by involving the students' engagement and this is can be gained with critical and creative thinking. Also, socially, the students interact among themselves, practice to share, to improve social tolerance, and actively learning to give social contribution for their group