ASSESSMENT  MODEL  FOR CRITICAL  THINKING  IN LEARNING GLOBAL  WARMING  SCIENTIFIC  APPROACH

Agus Suyatna, Undang Rosidin
PhysicsEducation Post graduate Study Program, University of Lampung 
asuyatna@yahoo.com

Abstract— Global warming may have an impact on food shortages, natural disasters, floods, economic disruption, massive migration, can even trigger a war. Learning and assessment of global warming is essential implemented to provide an understanding of the causes and impact of global warming on the life. Critical thinking assessment needed to foster the idea of solving the problem of global warming and its impact on life in the future. This study aims to: describe the students' understanding of the causes and effects of global warming for life, describing the need of critical thinking assessment, designing the critical thinking assessment on global warming learning using scientific approach that can foster the idea of solving the problem of global warming. Data were collected using a written  test on the junior and senior high school students and a questionnaire to teachers of physics in Lampung province. The data analysis includes qualitative  and quantitative analysis.  Design assessment  conducted through literature  review and expert validation. The results showed: (1) the students' understanding of the causes and effects of global warming for life is still low, (2) teachers of physics require a model assessment of learning global warming using scientific approach to foster the idea of solving the problem of global warming, (3) critical thinking assessment  on learning global warming using scientific approach, measure all indicators of critical thinking on every component of scientific approach using  techniques and test forms adapted to the indicator.

Keywords: assessment , critical thinking, global warming, scientific approach

I.	Introduction

Carbon emissions which continue to rise will cause the thickness of greenhouse gases in the atmosphere. This layer will forward the heat coming from the sun but will retain heat on the earth's surface which is called the greenhouse effect. The greenhouse effect is highly needed by all living things on the earth, because without it, the planet would be very cold. However, if the gases are excessive in the atmosphere, they will lead to global warming (1). One of the most critical environmental subjects of 21th century  is  Global  warming  (2). Intergovernmental Panel on Climate Change (IPCC) has concluded that most of the increase in global average temperature is most likely caused by the increased concentrations of greenhouse gases due to human activities. Global warming may have an impact on food shortages, natural disasters, floods, economic disruption, massive migration, can even trigger a war (3). Rising global temperatures are expected to cause other changes such as rising sea levels, increased intensity of extreme weather phenomena, as well as changes in the amount and pattern of precipitation. The effects of global warming include agricultural output, loss of glaciers and the extinction of various animal species (2). Greenhouse gases  (water  vapor, carbon  dioxide,  methane,  etc) are available existing in the atmosphere, trapping sunrays and making earth’s  atmosphere  warmer. Whereas some  of  these gases are  naturally found in the atmosphere, human activity increases the amount of particular gases (4-6). There are two main approaches to slow down the increase in greenhouse gases. First, protecting trees and planting more trees. Second, reducing the production of greenhouse gases, by reducing the burning of fossil. Both ways can be done if there is an awareness of the community about the impact of global warming.
People's knowledge about global warming is still low. This is demonstrated by the behavior and activities of the people which contribute to the thickness of greenhouse gases. Most of these greenhouse gases are produced by animal husbandry, burning of fossil fuels in motor vehicles, modern factories, farms, Nitrogen Oxide (NO) from fertilizers, and the gases used in refrigerators and air conditioners (CFC), as well as plants of electricity. The destruction of forests which should serve as storage of CO2 is also a contributor of greenhouse gases because trees that die will release the CO2 stored in their tissues into the atmosphere. Forest fires are also the largest contributor to greenhouse gases in Indonesia. 
The public's understanding of the causes of global warming and their impacts on life and the environment is very important. An understanding of this is expected to be able to form a disapproval of the behavior that can lead to global warming and foster the ideas to solve the impacts of global warming. Therefore, people need to be educated about the causes of global warming and their impacts on life and the environment. Educating  communities can be started at high school level which is part of the community. As students are among the most trainable stratums  of  the  society, it is essential to improve their  knowledge  and  perception  of  greenhouse  effects to  prepare  the  best  kind  of  educational  program  for them (7).
One of the educational efforts that can be done is applying critical thinking assessment on learning the scientific approach. Critical thinking assessment needed to foster the idea to solve the problems of global warming and their impact on life in the future. Critical thinking in  very  simply  stated,  the  ability  to  analyze  and evaluate information.   Critical thinkers raise vital questions and problems, formulate them clearly, gather and  assess  relevant  information,  use  abstract  ideas, think open-mindedly, and communicate effectively with others. Critical thinking is an important and necessary skill because it can help you deal with mental and spiritual questions, and it can be used to evaluate people, policies, and institutions, thereby avoiding social problems (8). They are involved in dialog, debate, writing, and problem solving,” as well as higher-order thinking, such as analysis, synthesis, and evaluation. The encouragement of critical  thinking  can  be accomplished in any content area by modification of lectures   and   the   incorporation   of   simple   active learning techniques (9). Indicators of critical thinking skills are the skill of asking and answering questions, considering whether the source is reliable or not, identifying terms and consideration of a definition, determining the action to be taken, and the skills to make a conclusion (10). These indicators will be used to design assessment of global warming with a scientific approach
Assessments have various purposes such as assessment for learning, assessment of learning and assessment to learning. To assess the critical thinking skills needs authentic assessment. Authentic assessment is defined as a real assessment. which measures the ability of students from all aspects. Authentic assessment is defined as an actual vote. It is necessary for assessment to a variety of techniques. A variety of assessment methods should enable to measure all aspects what students know and what the students do. Authentic assessment is based on scientific literacy which is a form of real assessment and meaningful for the students, which enable students to develop high-level thinking skills and scientific literacy containing dimensions (concepts, processes, and context) (11). Development of scientific literacy assessment instrument is based on an understanding of the concepts and methods of science, technology and the impact of science on the environment (12). The essence of this form of assessment is that the assessment is based on several sources. Something that clearly characterizes the application of authentic assessment is to measure all aspects of learning, including the process, performance and product (13). The benefits of using authentic assessment, are is as follows. First, the use of authentic assessment allows direct measurement of the performance of students. Second, authentic assessment gives an opportunity to the students to construct learning results. Then, authentic assessment allows the integration of the activities of teaching, learning and assessment activities into one integrated package. And finally, authentic assessment gives students a chance to show the results of their study, working performance, in a way that is considered the best (11).
Good planning should also be applied in the assessment activities that are part of the learning activities. Steps to be taken in the development of authentic assessment in global warming learning cover three aspects: (1) the assessment of attitude that includes self-assessment techniques and journals; (2) an assessment of knowledge using written test with a form of multiple choice questions and essay; (3) The skills assessment which includes an assessment of performance, project, and portfolio. Evaluation techniques are selected according to indicators of critical thinking on global warming learning using scientific approach.
This study aims to: describe the students' understanding of the causes and effects of global warming for life, describing the need of critical thinking assessment, designing the critical thinking assessment on global warming learning by using scientific approach that can foster the idea of solving the problem of global warming impact.
II.	RESEARCH METHOD 

The sample consisted of teachers and students. Sample of students were taken from 11 senior high schools and 7 junior high schools spread over the those in the Province of Lampung. The students who become the sample are who have studied the topic of global warming and those who have not. Details about the sample are presented in Table 1. The total sample of teachers is 15 people coming from 3 senior high school. 
TABLE 1. THE BACKGROUND OF THE STUDENT SAMPLE

School and grade	Already studying global warming	N	
Senior High School grade 11	yes	196	
Senior High School grade 10	no	126	
Junior High School grade 8	yes	165	
Junior High School grade 7	no	86	
Total	573	

The data were collected using a written test about global warming knowledge in the form of an objective test consisting of 15 questions. Each question has three choices, true, false, and do not know. Before using, the instruments validity and reliability were tested first. The data were analyzed using independent sample t-test,  one way ANOVA, and multiple comparison.  
The data are collected from the teachers using questioner about how teachers teach global warming, teaching problem, and the need for teachers to global warming learning program. This data was analyzed qualitatively. 

III.	RESULTS AND DISCUSSION
Results
The results of the written test, the understanding of global warming, are presented in Table 2. Knowledge about  global warming of student in Lampung Province was low.  The average of score 3.6 out of 10 scale. The average student only is able to answer questions correctly as much as 36%. The highest average score obtained by the student of grade 11 who have learned about global warming.
TABLE 2. STUDENT SCORE OF GLOBAL WARMING KNOWLEDGE

School and level	Already studying global warming	N	average	
Senior High School grade 11	yes	196	4.1	
Senior High School grade 10	no	126	3.6	
Junior High School grade 8	yes	165	3.5	
Junior High School grade 7	no	86	3.2	
Average	3.6	

The students learning experience of global warming influence have effected on test scores. This is indicated by one-way ANOVA test results, there was significant difference (p = 0.000 < 0.05) in scores obtained knowledge of global warming.
The results of a further test for the average difference in test results between grades and learning experiences of global warming are presented in Table 3. Average scores were significantly different that students grade 11 with grade 10, grade 8, and grade 7. otherwise there was no significant difference. It shows that global warming learning at the senior high school make differences in learning outcomes, while at the junior high school level is not. 
TABLE  3. MULTIPLE COMPARISONS OF STUDENT
(I) Class	(J) Class	Mean Difference (I-J)	Std. Error	Sig.	95% Confidence Interval	
					Lower Bound	Upper Bound	
2	1	-.4674*	.16333	.023	-.8883	-.0465	
	3	.1254	.15113	.840	-.2640	.5148	
	4	.4194	.18502	.107	-.0573	.8961	
1	2	.4674*	.16333	.023	.0465	.8883	
	3	.5928*	.16923	.003	.1568	1.0289	
	4	.8868*	.20008	.000	.3713	1.4023	
3	2	-.1254	.15113	.840	-.5148	.2640	
	1	-.5928*	.16923	.003	-1.0289	-.1568	
	4	.2940	.19024	.411	-.1962	.7842	
4	2	-.4194	.18502	.107	-.8961	.0573	
	1	-.8868*	.20008	.000	-1.4023	-.3713	
	3	-.2940	.19024	.411	-.7842	.1962	
Note:
*. The mean difference is significant at the 0.05 level.	
1.	Senior High School grade 11,  already studying global warming	
2.	Senior High School grade 10, global warming has not learned	
3.	Junior High School grade 8, already studying global warming	
4.	Junior High School grade 7, global warming has not learned	

Further testing was done to determine the effect of gender differences and interaction between the learning experience by gender using Two Way ANOVA. The test results showed no difference in learning outcomes due to differences in gender  and no interaction between the learning experience of global warming by gender (Table 4). 

TABLE 4. STUDENT TESTS OF BETWEEN-SUBJECTS EFFECTS	
Dependent Variable:   Score  	
Source	Type III Sum of Squares	df	Mean Square	F	Sig.	
Corrected Model	49.572a	7	7.082	3.461	.001	
Intercept	6560.369	1	6560.369	3206.303	.000	
Learning experience	37.582	3	12.527	6.123	.000	
gender	.634	1	.634	.310	.578	
Learning experience * gender	3.518	3	1.173	.573	.633	
Error	1156.038	565	2.046			
Total	8848.530	573				
Corrected Total	1205.610	572				
a. R Squared = .041 (Adjusted R Squared = .029)	
Discussion
Based on the first question, it is known that global warming is a natural event that there are 68% of students answered that the events of global warming is not a natural event which means that there is human intervention in it. Question numbers 2 and 3 are intended to elicit information about gases which trigger the greenhouse effect, 23% of students confirmed that hydrogen, helium and neon are greenhouse gases and 13% stated that animals such as cows produced greenhouse gases. It shows most students do not understand the gases which trigger the greenhouse effect. Question 7 regarding ozone obtained information that 81% of students believe that the holes in the ozone layer of the earth will increase the greenhouse effect, this is a misconception of the greenhouse effect. Question number 14 regarding the result of the greenhouse effect, as many as 58% of students stated skin cancers were caused by the greenhouse effect. In fact, skin cancer is caused by depletion of the ozone layer.
Based on the results of tests analysis and interviews with students, it can be seen the following matters. Student’s understanding on global warming can be grouped into three part: causes, impacts and solutions of global warming. Among the three sections, most do not understand is the cause and determine the solution. They are generally difficult to link the causes, impacts and solutions.
Students generally know the cause of global warming associated with the increase in the average temperature of the Earth's surface caused by rising greenhouse gas emissions. Greenhouse gases cause a phenomenon called the greenhouse effect. In general, the students can give the analogy of the greenhouse effect that they had experienced being in a closed car that is park under the scorching heat of the sun and feel the temperature on the car was very hot, but they were not able to explain exactly why it can happen.
Greenhouse gas emissions are considered dangerous that should be  controlled are: carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), O3, CCL2F2, CCl2F2, and sulfur hexafluoride (SF6). From the test results, it is found that there are a variety of student responses regarding greenhouse gases are considered dangerous. From the students' responses show that students do not understand precisely gases triggers the greenhouse effect.
The students understand that the greenhouse effect will have an impact on global warming that will be followed by climate change, such as increased rainfall in some parts of the world, causing flood and erosion. Meanwhile, in the other hemisphere will dry season due to the temperature rise,  but the students have not been able to explain exactly how the greenhouse effect affects climate change.
Most students an concerned concerned existence of global warming. Various efforts are known by students to overcome the impact of global warming include reforestation and reducing air pollution. They do not know that simple act such as: walking or go to school by bike, turn off the lights after they finish studying, saving paper consumption, and others can reduce greenhouse gas contribution.
These findings are not different from the results of Iranian research. The study shows high percentages of the students, belief that if the greenhouse effect gets bigger “the Earth will get hotter”, “there will be changes in the world’s weather” and “polar ice will melt”. These findings together with students’ low level cognitive scores  and  the  fact  that  students  cannot be used to describe greenhouse effect correctly and completely which indicate that the students know some points about global warming but their knowledge is not deep-seated. Despite of assuming “holes in the ozone layer” as a cause of greenhouse effect by most of the students, almost the same percentage of the students were aware of the fact that too much carbon dioxide and chlorofluorocarbons  are  causes  of  global  warming. The students are aware of the causes of the greenhouse effect. While more than two third of the students knew “not to use cars so much” and “planting more trees” are cures for global warming, about the same percentage of the students accepted this wrong idea that “using unleaded petrol is a way to reduce greenhouse effect”, therefore students’ knowledge about cures for greenhouse effect is not reliable too (7).
The results of the classroom observation indicate the learning process is centered on the teacher, the students tend to be passive in learning. The learning process tends to abstract, the teacher has not optimize the use of instructional media. Media used only pictures that are not attractive. Teachers have no implement a scientific approach in the learning process, as emphasized in the curriculum. From needs analysis questionnaire obtained information that the teacher wanted a model of learning, assessment models, and various media to study global warming.
Based on the results of a literature review prepared an assessment models to foster critical thinking skills in understanding of global warming and looking for ideas to solving the impact of global warming as presented in Figure 1. There are five stages of global warming learning to cultivate critical thinking skills. The stages of learning global warming are as follow. Observer, to observed the phenomenon of global warming that there are around students. Questioning, asking questions about the causes of global warming phenomenon. Explore, conducting experiments to determine the relationship between the phenomenon of global warming and its causes. Infere, determine the factors that cause global warming and looking for ideas to reduce greenhouse gases. Communicate, convey ideas and attitudes toward behavior that causes global warming. 

Scientific Approach

observe

questioning

explore

infere

observed the phenomenon of global warming

asking questions about the causes of global warming phenomenon

communicate

conducting experiments to determine the relationship between the phenomenon of global warming and its causes

determine the factors that cause global warming and looking for ideas to reduce greenhouse gases

convey ideas and attitudes toward behavior that causes global warming

Critical thinking skill

Explaining global warming

Detecting the effects of global warming

Analyze the causes and effects of global warming

Analyzing the impact of efforts to reduce global warming

Finding alternative solutions to global warming

Describing the attitude towards the prevention of global warming

Analyzing the greenhouse effect, carbon emissions and climate change

Figure 1.  Assessment Models To Foster Critical Thinking Skills In Understanding Global Warming Looking For Ideas to Solving The Impact

At each stage of learning execute the assessment of global warming according to indicators of critical thinking using  techniques and test forms adapted to the indicator. Indicators of critical thinking on global warming that are explaining global warming, analyzing the greenhouse effect, carbon emissions and climate change, detecting the effects of global warming, analyze the causes and effects of global warming, analyzing the impact of efforts to reduce global warming, finding alternative solutions to global warming, describing the attitude towards the prevention of global warming.
IV. CONCLUSSIONS AND RECOMENDATIONS

The results showed: (1) the students' understanding of the causes and effects of global warming for life is still low. There is a difference between knowledge of senior high school students who are studying global warming and that of those who are not learning, but in junior high school students no difference. There is no difference in learning outcomes due to differences in gender  and no interaction between the learning experience of global warming by gender,   (2) teachers of physics require a model assessment of learning global warming using scientific approach to foster the idea of solving the problem of global warming, (3) critical thinking assessment  on learning global warming using scientific approach, measure all indicators of critical thinking on every component of scientific approach using  techniques and test forms adapted to the indicator.
It is necessary to find the relationship between students' knowledge of the impact of global warming with their attitude toward behaviors that contribute greenhouse gases. 
It is necessary to develop learning models of global warming and media that can foster critical thinking skills in order to obtain innovative ideas to solving global warming impact. 
Acknowledgment 

Thanks submitted to the Directorate General of  Higher Education,  The Ministry of  Research, Technology, and Higher Education who has financed this research
References
1.	Wikipedia. Global Warming. Sumber: //id.wikipedia.org/wiki/pemanasan-global,  accessed  March 2011.
2.	Skamp K. R, Boyes E, Stanisstreet M, Global warming responses at the primary secondary interface: 1 students’ beliefs and willingness to act, Australian Journal of Environmental Education, 2009;25:15-30.
3.	IPCC. Climate change a threat to security, food and humankind - IPCC report. (http://www.theguardian.com/environment/2014/mar/31/climate-change-threat-food-security-humankind) , accessed  March  April 2014.
4.	Lee O,  Lester  BT, Ma  L,  Lambert J,  Jean-Baptiste  M. Conceptions of greenhouse effect and global warming among elementary students from diverse languages and cultures, Journal of Geoscience  Education, 2007;55(2):117-25.
5.	Marlon JR, Bartlein PJ, Carcaillet C, Gavin DG, Harrison SP, Higuera PE, Joos F, Power MJ, Prentice IC. Climate and human influences on global biomass burning over the past two millennia, Nature Geoscience 2008;1(10): 697-702.
6.	Mitchell  JFB,  Johns  TC.  On  modification  of  global warming    by    sulfate    aerosols. Journal  of  Climate, 1997;10(2):245-67.
7.	Taraneh Y, Sousan S, Mohammad RM, Seyed MS, Eddie B, Martin S, and Mirsaeed. A global warming: Knowledge and views of Iranian Students. Acta Medica Iranica, 2013; 51(3): 178-184
8.	Hatcher, D. L., & Spencer, L. A. Reasoning and Writing: From    Critical    Thinking to Composition. 3rd. Ed. Boston: American Press, 2005
9.	Robert D, Barbara L, Wendy W.   Critical thinking framework for any discipline, International Journal of Teaching and Learning in Higher Education, 2006; 17(2): 160-166
10.	Ennis, R. H. Critical Thinking. New Jersey: Prentice-Hall, 1996.
11.	Mueller.J.  The authentic assessment toolbox: Enhancing student learning through online faculty development. North Central College, 2005; 1(1): 1-7.

12.	Chiu, S. & Chang, M. The Development of Authentic Assessments to Investigate Ninth Graders Scientific Literacy. International Journal of Science and Mathematics Education, 2005;  3: 117-140.
13.	Wijayanti. Pengembangan autentik assesement berbasis proyek dengan pendekatan saintifik untuk meningkatkan keterampilan berpikir ilmiah mahasiswa, Jurnal Pendidikan IPA Indonesia, 2014; 3 (2), 102-108
14.	Duron, R., Limbach, B., & Waugh, W. Critical Thinking Framework for Any Discipline, International Journal of Theaching and Learning in Higher Education, 2006;  17(2), 160-166.