Consideration of the nature of science in a modern physics course

The current study examined the effect of considering the nature of science in the classroom on the worldview and knowledge of undergraduate students of physics education. It seems that the historical, cultural, and social situation of physics and physicists during the modern physics period, plus some implicit challenges about the philosophy of science help to promote the worldview and physical knowledge of undergraduate students. So, we sought to determine this issue on experimental and control groups of students during the course of modern physics. They were provided with two types of pre-exam and post-exam sheets followed by an interview. The responses to the exams and the interviews of the students were analyzed qualitatively. It was concluded that simply learning modern physics by the control group did not change their beliefs about science considerably while the experimental group show promotion on their worldview and physical knowledge.


Introduction
There are many questions in the field of modern physics throughout the history of science, and the progress of science has been made by providing answers to these questions.There are also some deeper questions which their answers make the answers to the last questions achievable.Questions like how do science processes and scientists work?How do society and culture react toward scientists and the scientific process?Is science limited or will science answer all questions finally?Is scientific knowledge reliable or unreliable?Therefore, a correct understanding of the nature of science (NOS) and the function of science is essential for any student or researcher who does not just seek to solve physics problems by rote.NOS combines aspects of different social studies of science like the history, sociology, and philosophy of science plus cognitive sciences like psychology.It aims to achieve a wealth description of science; what it is, how it works, and the interaction between scientists and society [1,2].Due to the importance of this issue and its reflection in science education, research in this field has been well performed in recent decades.The nature of science and scientific inquiry should be considered explicitly during science instruction equally to traditional subject matters [3].The nature of science confirms that scientific knowledge is not individually determined through observation or experience.This can change some of the resistance to conceptual change theory like thinking that knowledge of the natural phenomenon is completely objective and exists independently of the searching properties.Kippens found that the expression of the origin, development, correction, and replacement of theories throughout the history of science, as a part of the nature of science, helps the student's understanding of the scientific process in both subjective and objective aspects [4].Students that learn about science can interact with scientific explanations of the natural world and understand the evolution of science and participate in scientific activity.This vision could be applied to the curriculum image of science, scientists, and scientific procedure [5].Focusing on cognitive aspects of science, as Irzik and Nola proposed, "science is a cognitive system or pattern of practice and thought that involves such and such activities; values and aims at such and such; produces so and so using such and such methodologies and methodological rules."enables the teachers to define science in a nutshell [6].Although the importance of NOS in curricula is clearly determined [7], the effort to the application of NOS perspectives in the classroom is not developed well [8].In separate NOS inclusion, specific issues of science are mentioned regarding what NOS is, while considering NOS in connection to physics classroom contents makes it become part of physics teaching [9,10].These two methods are applicable, and they could be better used simultaneously while most of the curriculums and textbooks present the physics issues in an unchallenged and linear accumulation manner [11].The need for a comprehensive picture of science and scientific activities is quite evident.To express this comprehensive picture of science, the nature of science is used in science education.The definition of the nature of science includes [7]: characteristics of scientific research and investigation, the role and situation of scientific knowledge, the nature of models and modeling, how scientists work as a group of society, the linguistic agreements for reporting and analyzing knowledge, how science effects and is effected by the social context and the importance of NOS in addressing the Science Socioscientific Issues (SSI), and more recently, important plank for citizenship improvement.
Hence, the question raises: "Does teaching the modern physics course based on the nature of science have a positive effect on students' scientific worldview and scientific knowledge?".Finding an appropriate answer is the aim of the present study.To do this, we employed NOS by teaching modern physics issues.We try to propose solutions for modern physics challenges from different social, environmental, and cultural contexts before entering the content of the textbook for each issue.For instance, we discuss the theory of the atomic model which has a history of ups and downs and revisions as a representative of science.During teaching and discussing various situations we focus on the fixed aspects of science.These lasting properties of science make the nature of science explicit.This leads to understanding science and the scientific method, certainty level of scientific knowledge, and relation between scientific models and nature.

Research method
In this study, the subjects were the students of physics education in their junior year at university.Two groups of 26 and 30 students in the single-gender class took the modern physics course and participated in the inquiry.These two groups of students had passed basic courses including fundamentals of mechanics and electromagnetism.The classes were held under similar educational circumstances in the same semester.During the modern physics course of both classes, the textbook instruction was followed and these subjects were covered: some deficiencies of classical physics, the special theory of relativity, the particle-like properties of electromagnetic radiation, the wavelike properties of particles, the Schrodinger equation, the Rutherford-Bohr model of the atom and the hydrogen atom in wave mechanics.The group of 30 students was instructed by a traditional teaching method, called the control group, and the group of 26 students was instructed considering the nature of science through the teaching of each issue, called the experimental group.In the experimental group, the instructor was asked to explain some of the following topics in class during each section of the textbook by Kenneth S. Krane [12]: cultural and social influences on the content issues of modern physics, scientific method as an active, creative and non-unique procedure in modern physics, relationships between ideas, experiments, and data in modern physics, the subjectivity of some concepts of modern physics and the impact of personal views and biases into a different situation, common sense can filter the anomalies of environmental effects on modern physics.science and scientific methods cannot answer all questions of modern physics and limits exist, theories and laws in modern physics, the interaction of modern physics and technology, history of modern physics as a reflective mirror of its evolution and revolution.This teaching method helped the students of the experimental group to get foresight into modern physics.
By the beginning of the course, the students of both groups were pre-tested separately for their views about science and their modern physics knowledge acquired in high school and fundamental physics courses.By the end of the term, the students of both groups were post-tested for their scientific worldview and their knowledge of modern physics issues though in the class.The questions were identical and novel for both groups.After the examination, students were interviewed about their answers to scientific worldview questions.
All tests and interviews were performed after taking informed consent from the students and instructors.The students were assured that the results of the test and their statements in the interviews would not have any effect on their final assessment.Also, both instructors were said that the outcomes of the class would not be considered to review by their departments and the results were kept in the possession of the researchers.Because of the limited size of samples, the investigation of the results is more qualitative.The statistics report and tables given in the current article present a numerical perspective about each level of scoring.

Teaching strategies
The instructor of the control group applied the typical teaching method and follow the contents of the textbooks purely.In each chapter, after introducing the new topic of modern physics and the mentioned experiments, the instructor derives the relations and solved the related examples.There was no extra attempt to challenge the students with the issues presented in sec 2 unless a little history of science in some chapters of Krane.The instructor of the experimental group performed some of the following activities for each chapter in addition to typical teaching: Discussing all or some of the nine issues presented in sec 2 that could be related to the thought subject, Challenging the students with a different situation from the situation of experiments provided in the textbook, Asking the students about the resulting theories or laws emerged from the scientific procedure primarily, introducing and reviewing related books, movies and documentaries about the scientists and history of science and technology.

Examination
Here we evaluate the effect of NOS-based teaching on the level of the scientific worldview and scientific knowledge of students in a modern physics course.To examine these two kinds of abilities the students were asked to complete two kinds of tests separately at the beginning and end of the course.The scientific knowledge tests included different levels of questions and problems based on Krane.The questions and problems were equivalent for both groups and the instructors confirmed that they had not answered them as examples or exercises in the class.To evaluate their modern physics knowledge gained by the course with no serious NOS consideration, the pre-test was taken two weeks after the beginning of the course as a short quiz.The post-test was taken at the end of the course after the full application of NOS for the experimental group.The scientific worldview tests were derived inferentially from the most important concepts of NOS including the difference between science, art, philosophy, and religious prospectives, social and cultural influences on scientific ideas, inferential nature of scientific models, empirical nature, rational arguments and skepticism bases of scientific knowledge, objective and subjective components of science, scientific theories are explanatory while scientific laws are descriptive, creativity and imagination of scientists rather than the single scientific method.Each student of both groups was interviewed right after the worldview test.They were asked to describe their deduction from the course and how they arrived at their answers.

The questions of the worldview pre-test and post-test
The multiple choice questions of the world view pre-test and post-test are presented here.These questions were created by researchers and are confirmed by expert people in the philosophy of science, history of science, and physics.The questions of both tests are designed so that each question could ask participants about multiple aspects of NOS implicitly.The validity of responses could be assessed by the researcher, however, the reasoning behind students' responses and symbolization could not be achieved without interviews.

pre-test
1. What is the main purpose of sciences like physics, chemistry, and biology?a) simplification, arrangement, and explanation of world phenomenon b) presenting a rational model for a complicated phenomenon c) prediction of the future phenomenon by creativity d) simulation of a phenomenon in the laboratory 2. Two theories can explain a phenomenon very well.Which one is more acceptable in the scientific community?a) a theory that has fewer mathematical relationships b) a theory that has fewer assumptions c) a theory that contributes to the further development of technology d) a theory that is more compatible with the culture and beliefs of society 3. What is the main function of a contemporary experimental scientist such as a physicist, chemist, or biologist who researches to advance science?a) studying a lot in his specialty and correcting previous mistakes b) engaging in modeling and theorizing due to wisdom and thinking c) collecting experimental data and trying to describe the results d) engaged in collecting experimental data, modeling, and predicting the results of similar experiments 4.There is a black box containing a container with an unknown shape and physical condition.
One liter of water is poured into a black box and 0.75 liters of water comes out of the black box.What do you think the container inside the black box is like?a) the container is perforated and 0.25 liters of water is poured from the container into the space inside the box b) because the information is not enough, no guess can be made c) the temperature of a part of the container is so high that 0.25 liters of water have evaporated d) options a and c can both be correct.a) Newton's Laws of motion started as theories and eventually became laws after proven demonstration while Einstein's theory of relativity is not demonstrated yet.b) Newton's laws of motion describe relationships between objects of attraction phenomena while Einstein's theory of relativity proposes a new explanatory model for the world.c) Einstein's theory of relativity has not been proved to the satisfaction of the scientific community while Newton's laws of motion have been.
d) Einstein's theory of relativity can not be completely tested while Newton's laws of motion can be tested in everyday life.
post-test a) indirect evidence can corroborate theories and link things that are not directly seen.b) if there is no direct evidence, it will inevitably lead to incorrect theories, such as the geocentric theory, which was formed due to the absence of a telescope.c) the evidence must be direct to prove the theory.Like seeing atoms with powerful microscopes that prove atom theory.d) indirect evidence in science gives temporary theories and must be corrected in the future.5. Which statement is true about scientists?a) the method of scientists is independent of themselves and the interpretation of the evidence is the same in all of them b) scientists, like all human beings, offer different interpretations of the evidence, influenced by their background and environment c) only the interpretation of a group of scientists about evidence is acceptable in science, not the interpretation of a scientist d) scientists are not allowed to use their creativity and imagination during facing evidence 6. Scientific theories . . .a) are perfectly proven b) are made by creativity at first and examined secondly c) mostly need to be corrected d) provide a framework for current knowledge and future studies.7. what is the state of creativity in advancements of science?a) creativity is allowed in science unlimitedly b) analogy as a sample of creativity is forbidden in science c) unlike art, everything is the same for all scientists and the creativity of scientists should not be used in different stages of the scientific method and the birth of a theory d) like artists, scientists use their creativity at different stages of the scientific method but they justify it with evidence.8. What is the difference between a scientific theory and a scientific law?a) scientific laws and theories both predict the results of certain initial conditions but laws are more reliable b) scientific theory must be tested several times to become a scientific law c) scientific law is perfectly valid and unchangeable, but the scientific theory may change or not be validated after testing d) scientific law describes the relationships between phenomena, while scientific theories explain why things happen logically As it is obvious, the average scores of the students of the experimental group in the pre-test and posttest of scientific knowledge are %51 and %89.3 in percentage respectively.They are %47.5 and %66.6 for the control group.The difference in scores of their post-test shows that teaching based on the nature of science has had a significant impact on the responses of students to the scientific knowledge test.The average score of the scientific worldview in the experimental group increased from %37.5 to %88.9, while this growth in the control group is from %39.9 to %67.08.These results show that although the mean score of the pre-test of both groups is comparable, their scores on the post-test are rather different and the promotion of the experimental group is considerable.Consequently, Most of the students of the experimental group arrived at the correct answers to the textbook-based questions and problems and got better scores, also their deductions of the course content affect their scientific worldview.So it seems they could get better results in both fields.

pre-test
Fifty percent of the experimental group and %36 of the control group answered question 1 correctly by choosing the choice 'a'.Those who did not answer correctly mostly chose 'b' and they believe in rational explanation of the world.Question 2 seems newer to the experimental group and it seems they had a naive background in scientific theory.Almost %27 of the experimental group and %73 of the control group chose 'b' as the correct answer." A theory should be understandable for most people so fewer assumption is preferred" responded most of the students in the control group with the correct choice.Those students of both groups who did not answer correctly often chose or 'c' and some of them considered science in the service of technology.Question 3 assesses the perspective of students about recognition of what scientists do.The results say that more than half ( about %57 ) of both groups chose 'd' as the correct answer.Those who answer incorrectly often chose 'c' which expresses their carelessness." I know experimental data is essential for scientists but I guess describing the results is their main duty.I do not care about prediction" responded one of them.Skepticism and inferential concept of scientific models is mostly intended in question 4. Just a few students of the experimental group (%7.6) answered correctly by choosing 'd'.Also, only %20 of the control group chose 'd'.Most of the students chose 'b' and they need more data to propose a model." Because several predictions are possible, I am not able to choose the best one.More detail is needed." said one of the students of the experimental group who chose 'b'.It is considered that only a few students of both groups chose 'a' or 'c', It shows they do not consider the crisis in scientific models, and proposing more than one model for a phenomenon is unfamiliar to them.
Seventy-seven percent of the experimental group could answer question 5 correctly and choose 'd'.Almost half of the control group (%47) answered correctly." I do not have historical information but I guess just one model is suitable for phenomena and two models make chaos in the scientific society.So Copernicus model was ignored." said one of the students of the experimental group with the right answer.The other students of both groups with the wrong answer mostly chose 'c', they claimed since they have heard about Galileo Galilei's story against the church, they guess Copernicus was like that.You need to know what is going to come out to organize a scientific experiment.This fact is addressed in question 6 which %69 of the students in the experimental group and %36 of the control group chose the right option 'd'." Having bias may affect the results of the experiment."," everything must be original and virginal during a scientific test so that scientists wonder at each level.This is like what we watch in scientific movies and stories.",often said some of them that chose 'a', 'b' or 'c'.Question 7 seems the most challenging question.None of the participants in the experimental group and just %3 of the control group chose 'c' as the correct answer.Most of both groups chose 'b' and 'd' as the correct answer.They mostly do not believe in inspiration in science and they were sure 'c' is incorrect so they thought about other choices.Some of them believe in the everlasting of contemporary scientific models in comparison to previous ones and they chose 'b'.This is a naive imagination about contemporary science among people.The choices 'a', 'c', and 'd' of question 8 are the common understanding of scientific laws and theories and about %70 of both groups chose them.They believed demonstration and testing several times is the difference between theory and law.This is a typical mistake even among academic people.Those that chose 'b' claimed they had faced this challenge before and had asked or searched about it.

post-test
Eighty-four percent of the experimental group and half of the control group answered question 1 correctly by choosing the choice 'd'.The students of both groups that chose the correct answer confirmed that all three first choices were responsible for the Ptolemaic geocentric model.Those who did not answer correctly mostly chose 'b' and their most repetitive reason was the lack of a precision telescope to observe the planets which seem a primary came to mind answer.Choice 'c' was also chosen by a few students of the experimental group which shows they could consider culture effectively.Question 2 seems challenging and 88% of the experimental group and 70% of the control group chose 'c' as the correct answer." Although everybody, like artists, feels free to express their interpretation of the world, scientists try to confirm their interpretation with data" responded similarly to students in the experimental group." Scientists try to express the hidden facts of the world while artists interpret the facts as they wish." said most of the control group that chose 'b'.Question 3 is completely perceptual and asses the perspective of students about science, philosophy, and religion.The results say that most of the control group (80%) and almost all of the experimental group, except one, chose 'b'.It shows that the student who does not challenge the empirical concept of science does not expect total changing in science.Those who answers incorrectly claimed that "our living world contains fixed laws which will never change and the will only improve with more detail like Galilean relativity which promotes by transformations".Students of the experimental group used examples like an atomic model of Dalton or Rayleigh-Jeans law for short wavelengths totally changed during modern physics.The inferential concept of scientific models is mostly intended in question 4. Most of the participants of the experimental group (80%) answered correctly and they chose 'a'.Interestingly, even %63 of the control group can conclude the usefulness of indirect data and some of them use the Schrodinger equation for invisible quantum-mechanical system or Bohr atomic model as an example."Prediction is the main issue of models and does not need direct evidence" said one of the students of the experimental group.Eightythree percent of the control group who could answer question 5 correctly and chose 'b' were aware of the effect of the atmosphere on the interpretation and world view of the scientist as a human being.Almost all of the experimental group (except one) answered correctly and one of them gave a nice example: " each scientist has a special perspective, when a cat is jumping down a wall a physicist tries to calculate its speed and acceleration, a biologist looks at its joints and muscles and a philosopher thinks about the existence of cats"." Michelson-Morley experiment to detect the velocity of the earth was affected by ether which was the accepted at that time" said the other one.choice 'a' was the most chosen by others in the control group because they believe in the objectivity of science.
Proving anything in science is an impossibility and evidence is only the quantities we can observe.They confirm theories and do not prove them, theories are empirical according to current data and may change after a while or not.These facts are addressed in question 6 which most of the students in the control group (%83) and %96 of the experimental group chose the right option 'd'." Considering the deficiency of many theories we had studied during the course, I chose 'c'", said one of the control group participants."As I studied the book a brief history of time: From the Big Bang to Black Holes by Stephen Hawking I know the main issue of a scientific theory." said one of the right answered participant from the experimental group.Question 7 is about permission and the amount of using creativity in science and comparing it with art.About %76 of the experimental group and %83 of the control group responded correctly and chose 'd'.They mostly said " If there is no creativity there will be no promotion and people must follow the previous rules" and they mentioned Einstein's theory of special relativity as a creative theory.Twenty-four percent of the experimental group mostly chose 'a' and they did not consider the limits of justification with evidence.Those students of the control group with an objective view to science chose 'c'.
The choices 'a', 'b', and 'c' of question 8 are naive understanding of scientific laws and theories, and %77 of the students in the control group chose them.They believed repetition and confirmation of a theory change it into law.Some of them think theories might not be true but laws are certainly true.Ninetytwo percent of the experimental group chose 'd' correctly and they refer to Newton's laws, thermodynamics law, the wave theory of light, or Einstein's theory of special relativity which correspond to choice 'd'.

Control group issues
The most common perception of science as obtained from the answers of post-test and interview of the control group are: %57 of them can recognize the perspective of science, art, philosophy, and religion, %66 of them consider the effects of the environment on the perspective of scientists almost well, %62 of them think science is unchangeable facts discovered by scientists, %62 of them believe indirect evidence are temporary for science and they must be replaced by direct evidence in future, %78 of them insist on objectivity concept of science, %53 of them believe that scientific laws are more reliable than scientific theories, %83 of them do not consider the substantial role of creativity for scientists.

Experimental group issues
The most common perception of science as obtained from the answers of post-test and interview of the experimental group are: %87 of them can recognize the perspective of science, art, philosophy, and religion, %90 of them could consider the effects of the environment on the perspective of scientists well, %91 of them think science has evolutionary nature and nothing is permanent certainly, %91 of them believe in inferential nature of scientific models and indirect evidence are effective for predictive models, %87 of them can consider both the subjectivity and objectivity concept of science, %94 of them fairly know the scientific laws and scientific theories have different uses but some of them are still confused with their power and reliability, %89.7 of them are aware of creativity of scientists to give birth to a model.

Summary and Conclusions
Generally speaking, considering the nature of science in teaching science is very essential and strengthens scientific literacy, scientific worldview, and scientific knowledge.Active learning of science should go beyond the simple view of reading, writing, memorizing, and solving problems traditionally, it should prepare thoughtful and literate people implicitly.The present study examined the effect of employing NOS through teaching modern physics issues.
Analyzing the scores of the scientific worldview test and scientific knowledge exam showed that the average scores of the experimental group grew more than the control group.Contents of subsection 5.3 show the higher average score of the control group belongs to the issue of considering creativity's role in science and the lower one is for understanding the difference between scientific theory and law.Contents of subsection 5.4.show the higher average score of the experimental group belongs to the issue of the understanding difference between scientific theory and law and the lower one is for considering both subjectivity and objectivity of science.These results show that NOS-based modern physics course effect significantly on the understanding of students about scientific theory and law.The students of the control group were more successful in the issue of subjectivity and objectivity of science, it shows the content of Krane's was rather sufficient for them.In comparison to other issues, our NOSbased teaching method needs more work on the subjectivity and objectivity of science.Consequently, the answer to the research question is evaluated as positive, and teaching a new physics course based on NOS has a positive effect on the scientific worldview and scientific knowledge of the participants.
The effect of NOS-based teaching in other branches of science is also considerable.As an example, Nelson and his colleagues [13] indicate that misunderstandings of NOS contribute to resistance against evolutionary theory among academic and non-scientific audiences.Their research shows that better acceptance of the scientific validity of evolution arises by using NOS and, conversely, evolution theory affects considerably audiences to develop their understanding of NOS.Finally, The following suggestions are provided for the undergraduate physics curriculum, and also other branches of science: 1-NOS should be included in undergraduate courses implicitly to improve the scientific literacy and knowledge of students.
What is the main difference between art and science?a)art deals only with beauty, but science deals with everything.b)the artist interprets the world, but the scientist expresses the facts of the world.c)the artist presents his or her interpretation of the world, but the scientist gathers data to support his interpretation.d) the scientist is not creative, but the artist is creative.3. which statement is correct about innovation in science?a) scientific theories do not change, they are only improved and refined by scientists.b) Unlike religious beliefs, everything in science can change with new evidence, and nothing in science is certainly true.c) scientific laws do not change at all while scientific theories may change.d) philosophy issues are variable since it is not based on experimental data while scientific issues never vary.4. What are the effects of direct and indirect evidence on the advancement of science?

Table 1
shows the mean scores of the pre-test and post-test of scientific knowledge and scientific worldview for the control and experimental groups.The ability of the students to reflect on what they have learned is examined through the scientific knowledge test.To test the results for the normality of the distribution we use the Shapiro-Wilk test.The significance level value of the Shapiro-Wilk test of the pre-test and post-test of the experimental group are 0.708 and 0.2.These values are 0.99 and 0.069 for the control group.They are all greater than 0.05 and it shows that the data have normal distribution.

Table 1 .
The mean scores of pre-test and post-test of scientific knowledge.