Development of The Online Assessment Instrument for Fluid, Temperature, and Heat to measure the problem solving skills of high school students

Assessing learning is very important. During a pandemic an assessment could not be made directly. Therefore, the development of online-based assessment is still very much needed. In assessing learning, test instruments are needed. The test instrument serves to reveal a fact into data, so that if the instrument used in the study has good quality and is reliable or commonly called valid. Online assessment instruments can be made in various platforms and can be filled with questions that have been developed. This study aims to produce an online assessment instrument for fluid, temperature, and heat materials to measure the problem solving skills of high school students that are valid and reliable. The research conducted is included in the type of research and development (research and development) using the ADDIE design. The subjects of the scale trial were 60 students of class XI IPA. Expert validation data were collected by questionnaire. The trial data were collected by means of essay tests and questionnaires. Determination of the value of expert validity using the Aiken’s V formula. The empirical validity of the instrument was measured using the product moment correlation formula. Instrument reliability was measured using the Cronbach Alpha formula. The results showed that online assessment instruments on fluid, temperature, and heat materials to determine the level of problem solving skills of high school students were included in the valid and reliable categories.


Introduction
Education is an important part of life.Education plays a major role in the development of human civilization.Education in the 21st century is required to think well, how to work and skills to create works in various fields.Education in the 21st century emphasizes or demands more in creating quality resources [1,2,3].Learning in the 21st century must use the use of ICT in learning.Both teachers and students are required to be able to keep up with the times that exist at this time.Teachers are expected to be able to design learning that is creative, active and innovative in using technology in the teaching and learning process to create more active and enjoyable learning.Assessment of learning outcomes can also use technology [4,5].The Covid-19 pandemic is the biggest international disaster that affects all aspects of life.This pandemic is considered a dangerous epidemic because it spreads very quickly.According to the World Health Organization (WHO) this corona virus outbreak began to spread globally on March 11, 2020.The spread of this virus greatly affected all sectors of life [6,7].Therefore, various efforts are needed to contain the spread of this disease outbreak.In the world of education, efforts are made by issuing government policies to conduct online learning.Online learning is carried out with the support of the use of technology [8].
The use of technology in online learning can be in the form of distance learning using zoom meetings, e-books, supporting learning media and online assessments.The use of technology in the assessment can be done by creating an online assessment instrument.Online assessment instruments can be accessed using laptops or smartphones, making it easier for students to work on them and making it easier for teachers to get the results of their assessments.Assessment using online assessment instruments can be used in various subjects at school.There are many subjects that must be in school, one of which is physics.The Covid-19 pandemic is the biggest international disaster that affects all aspects of life.This pandemic is considered a dangerous epidemic because it spreads very quickly.According to the World Health Organization (WHO), this corona virus outbreak began to spread globally on March 11, 2020.The spread of this virus has greatly impacted all sectors of life.Therefore, various efforts are needed to contain the spread of this disease outbreak.In the world of education, efforts are made by issuing government policies to conduct online learning.Online learning is carried out with the support of the use of technology.The use of technology in online learning can be in the form of distance learning using zoom meetings, e-books, supporting learning media and online assessments.The use of technology in the assessment can be done by creating an online assessment instrument.Online assessment instruments can be accessed using laptops or smartphones, making it easier for students to work on them and making it easier for teachers to get the results of their assessments.Assessment using online assessment instruments can be used in various subjects at school.There are many subjects that must be in school, one of which is physics.A problem will arise if a person wants to do something but does not know the action required to get what he wants.The process of solving problems requires a series of interrelated decisions, i.e. subsequent decisions depend on the results of previous decisions.A person who can solve problems has a well-organized knowledge structure.Problem solving skills as one of the achievement targets in learning physics, it is necessary to have an assessment instrument that will be used to assess the achievement of students' problem solving skills.There are four steps that can be taken to solve the problem [9], namely understanding, planning, carrying out plans, and reviewing the completeness of problem solving.. Instrument assessment can be made in printed or non-printed form.Assessment instruments in printed form are commonly used by teachers in various schools, while non-printed forms are rarely used in schools.Non-printed assessment instruments can be in the form of online assessment instruments.Online assessment instruments can be made in various platforms and can be filled with questions that have been developed.The question is submitted to the flatfrom.The questions given on the test are an assessment instrument to measure problem solving skills.Thus students can work on these questions online, and teachers can access student answers online as well.The results of student answers will be checked by the teacher, without face-to-face meetings.The assessment process in online learning will also be easier.To measure students' problem solving abilities easily, an online assessment instrument was developed to measure students' problem solving abilities, especially high school senior students.

Research Method
This research is research and development.Research and Development (R&D) is research that produces new products.Products that can be produced in the field of education can be in the form of models, media, equipment, books, modules, evaluation tools and learning tools.[10].The model used in this development follows the ADDIE model.The stages of analysis, design, development, implementation and evaluation need to be carried out in the use of the ADDIE model [11].Data collection is used to obtain data in the field.Expert validation is used to collect content validity data.The test questions were used to get the value of the empirical validity and reliability of the developed instrument.The research instrument is a tool used to measure observed natural and social phenomena.The phenomenon in question can be referred to as a research variable.The research instruments used were questionnaires and essay tests.The research subjects in this study were students who were in class XI.The number of students who became the research subjects were 60 students.Data analysis techniques with regard to calculations to answer the formulation of the problem.Instrument data analysis techniques by experts using descriptive statistics.The weighting is done through a Likert scale.Analysis of instrument validity data by experts using Aiken's V coefficient.Validity value using Aiken's V .formula [12]: Based on the value of V obtained, then categorized as in The data analysis technique of the test results of the instrument is divided into two, namely validity and reliability.The method of testing the validity of the instrument trial uses the product moment correlation [13].An item is be valid if the rcount>rtable from the calculation of the formula can be known whether the instrument is valid or not.Reliability test aims to test the accuracy of the instrument in measuring what is being measured.The reliability test in this study was carried out using the Cronbach Alpha formula [14].
The reliability criteria of this instrument are based on Table 2 below:

Result and Discussion
This development process is carried out through the stages of the ADDIE development model which consists of five stages: analysis, design, development, implementation, and evaluation.Based on the process and results of research that has been carried out in these five stages, it can be described as follows:

Analysis
The analysis phase aims to analyze the curriculum, materials, student characteristics, and instrument analysis.In the curriculum analysis, it was found that the materials for fluid, temperature and heat were in class XI in odd semesters.Material analysis resulted in KD and performance indicators on fluid, temperature and heat materials.The fluid learning material is divided into 2 KD, namely static fluid KD 3.3, dynamic fluid KD 3.4, and for temperature and heat it is at KD 3.5.Analysis of student characteristics resulted that of the 60 students who would be the subject of the study there were 36 female students and 24 male students.The instrument analysis aims to determine the assessment instrument used by teachers.The assessment instrument used is an assessment instrument that contains questions derived from books used in the learning process.In the high school there is no assessment instrument that is used specifically to measure students' problem solving skills.

Design
The design stage aims to make a design for making assessment instruments.In the design stage, the purpose of making the instrument is determined.Making the instrument aims to measure students' problem solving skills and can be done online.The assessment instrument is designed to be an essay question in which each sub-material will be given a different problem or story.• Recheck troubleshooting steps • Checking the magnitude and units of answers

Developmennt
The development stage in this research has 2 parts, namely instrument writing and instrument validation.
In writing the instrument, an online assessment instrument is produced which can be filled with questions that have been developed.The question is submitted to the flatfrom.The questions given on the test are an assessment instrument to measure problem solving skills.Students will be given a question link to work on online questions.At the instrument validation stage there are several parts: a. Validation instrument validity Validation of the validity instrument was carried out by 3 experts.The data obtained from the results of the validity of the instrument validation can be seen in table 3.  1, it can be concluded that the instrument validity is in the valid category.If this instrument has been tested for validity by an expert, it can be used to measure the validity of the online assessment instrument that will be developed.This is in accordance with the literature which states that if the validity instrument has been validated, then the instrument can be used to validate the product [14].

b. Validation of online assessment instruments by experts
The validation of the online assessment by the expert was carried out by 3 experts.There are 4 components in expert validation, namely content, construct, technical, and language validation.The results of content validation have 2 components, namely the assessment component and the feasibility of the content of the assessment.The results obtained from the validation of the assessment instrument by experts on content validation can be seen in tables 4 and 5  4 explains that all components that must be validated by experts are complete.The assessment was carried out by 3 experts by stating whether the instrument to be used existed or not.After all components are available, further validation can be carried out.The validation of the assessment instrument is divided into several parts, namely content validation, construct validation, technical validation, and language validation.Each validation section obtains a validation score with a valid category.In line with that, Selvia stated that validity is done to measure the level of validity of an instrument and product.Validity tests are carried out to determine the feasibility of instruments and products made based on the results of validators who are experts in their fields so that the advantages and disadvantages can be known [17].So it can be conclud that the online assessment instrument is feasible to measure problem solving skills [14].
c. Validation of online assessment instruments After validation by experts and declared valid, then proceed with trials to produce the validity of each item.The trial was conduct on 60 students.The following results obtained can be seen in table 9 From table 9 there are 20 valid questions and 5 invalid questions.Valid questions mean that they can be used while those that are invalid are discarded.In accordance with research conducted by Marselina, Sadhu & Laksana, and Utami stated that an instrument that has been tested for validity can measure what is to be measured and the results of this empirical validity will show the level of validity or accuracy of each item that exists and is based on empirical facts [18,19].

Table 2 . Instrument reliability criteria Correlation coefficient
[15,16]stions developed are able to measure the level of students' problem solving skills.Stages of problem solving according to Polya and Indicators by Selcuk[15,16]:

Table 3 . Validity Test Results of Validation Instruments
Instrument validity before being used must be validated first by experts.Based on table 3, it can be concluded that the validation instrument obtained a validity score of 0.86.By comparing the validity scores obtained with table

Table 5 . Validity Test Results of Online Assessment Instruments (Content Validation: Feasibility of Assessment Content)
Based on table 5, it can be concluded that the validation instrument obtained a validity score of 0.83.By comparing the validity scores obtained with table 1, it can be concluded that the instrument validity is in the valid category.Then the results of the online assessment instrument validation test on construct validation can be seen in table6