The ability to organize and teach effectively is crucial in today's academically and socially diverse classrooms. However, achieving effective planning and teaching processes based on different learner needs can be a challenging and problematic skill since the learner population is becoming more and more diverse in terms of gender, color, nationality, ethnicity, race, the language spoken at home, economic status, interests, readiness to learn, preferred modes of learning, self-awareness, confidence, at home, economic status, interests, readiness to learn, preferred modes of learning, self-awareness, confidence, independence, and information and communication technology (ICT) abilities, etc. (Boelens, Voet, and De Wever, 2018; Dosch & Zidon, 2014; Kamarulzaman, Md-Yunus, Azman, & Mohd-Zahidi, 2021; Onyishi, 2022; Santangelo & Tomlinson, 2009; Tomlinson & Imbeau, 2010). However, today, the majority of teachers have received little to no training to work effectively with this diversity and manage the learners in the same class who have above-below or average potential (Kamarulzaman et al., 2021). The findings of numerous studies revealed that instructors' practices, mostly based on lecturing with added discussions, are a poor representation of the various student bodies (Boelens et al., 2018; Joseph et al., 2013;; Santangelo & Tomlinson, 2009; Tomlinson & Imbeau, 2010). Additionally, Santangelo & Tomlinson (2009) noted that educational practices (such as the curriculum, physical layout, teaching processes, testing methods, etc.) had not changed significantly to take into account diverse students' experiences and learning needs. For this reason, there is an urgent need to strengthen teacher competency in dealing with the diversity-related issues that arise in classrooms. In this regard, Carol Tomlinson's (1999b) "Differentiated Instruction (DI)" was recommended.

DI is seen as both a philosophy and a model for teaching (Tomlinson & Imbeau, 2010). The content, process, product, affect, and learning environment differentiation are five areas of DI implementation, and they are based on learner readiness, interests, and learning profiles (Tomlinson, 2001). The ‘content’ refers to the information or skills taught, while the ‘process’ is how students interpret, adapt, and own the content. The ‘product’ is how students express what has been understood, learned, and implemented after having received instruction. The ‘affect’ is how students feel in the instructional environment. The ‘learning environment’ refers to both the physical and the affective climate in the classroom, and it is the weather that affects everything that happens there (Santangelo & Tomlinson, 2009; Tomlinson & Imbeau, 2010).

As it is stated that preservice teachers who did not have DI modeled for them in their teacher education programs did not have knowledge of how to apply DI in their own classes after they started teaching in the K–12 environment (Tomlinson, 2001) and lacked confidence and had limited perspectives on curriculum and evaluation approaches that would accommodate learning differences (Wan, 2015), the purpose of this study was to implement differentiated instruction materials in the curriculum development in education course and investigate the effect of differentiated instruction on student achievement, planning abilities, and perceptions related to the technology rich outcome focused learning environments.

Based on the main purpose of the study, the following research questions were proposed:

• Is there a significant difference in pre-service teachers' (PST) beginning and ending semester grades based on lesson plan grades?
• Does the classroom environment's perception by pre-service teachers predict their course achievement?
• What are the perceptions of pre-service teachers about differentiated instruction, the planning process, and the classroom environment?

Method In this study an explanatory mixed-methods research design was used (Creswell, 2012). The study was conducted during the fall semester of 2022–2023 for 11 weeks at a state university in the curriculum development in education course. Participants In the beginning of the semester, 61 willing PST completed the pre-course learner background questionnaire and prepared lesson plans. 53 of them prepared lesson plans at the end of the semester and completed the Technology-Rich Outcomes-Focused Learning Environment Inventory (TROFLEI). 43 (81.13%) of them were female, and 10 (18.87%) of them were male. In the qualitative part of the study, 15 pre-service teachers were selected according to the maximum variation sampling method to represent the diversity of perspectives or characteristics (Fraenkel & Wallen, 2009). Instruments for Data Collection In this study, a learner background questionnaire, semi-structured interviews, and Welch, Cakir, Peterson, and Ray's (2012) TROFLEI were implemented. PST’ planning the instruction scores and course grades was obtained from the course instructor. The questions for semi-structured interviews were adapted from literature (Danley & Willliams, 2020; Kokkinos, 2020; Santangelo & Tomlinson, 2009; Tomlinson, 2001) and implemented by taking the opinions of experts. Procedures for Differentiated Course In this study, PST were asked to prepare a lesson plan at the beginning of the semester on a subject of their choice for either primary or secondary level (differentiation of content based on student interest) to disclose their level and skills in preparing lesson plans and to assess whether they need early scaffolding to learn major course core topics (differentiation of content based on student readiness). PST were assigned three articles each week from well-known educational journals and books, taking their readiness levels into consideration. They were expected to write their reflections through blogs, use the Padlet platform, etc., or create podcasts, publish Youtube videos, etc. As for the process differentiation, different activities were implemented concurrently. In addition, at the end of the semester, while a group of learners preferred to be assessed with a multiple-choice test, another group preferred to be assessed by preparing a comprehensive take home exam that included higher-level questions (differentiation of product). Data Analysis This study's data were analyzed through descriptive and inferential statistical analysis techniques using the Statistical Package for Social Sciences (SPSS, 22.0) (Field, 2009) and qualitative data were analyzed via the content analysis method (Miles, Huberman, & Saldaña, 2014).

According to the findings of this study, there is a significant difference in PST’ beginning and ending semester grades based on lesson plan grades. The classroom environments perceptions of pre-service teachers did not predict their course achievement; however, their perceptions of differentiated environments were positive. As for the experiences of PST, they focused on the lack of time for learners’ initial assessments as one of the most significant difficulties for differentiating their lesson planning. Moreover, they found difficulties in grouping students according to their interests, learning profiles, and readiness, in which they especially stated that the differences between the low and middle; high and middle readiness groups were not so clear. Their concern is related to classroom management issues; because if they are unable to plan effectively, their implementation may fail in a real classroom situation. Also, they stress their gain as a more accurate sense of time and its contribution. Moreover, they emphasized their concerns regarding finding enjoyable and suitable activities according to their students’ interests, learning profiles, and readiness. According to PST, the quality of interaction in differentiated learning environment positively affected their perceptions of the classroom environment and also helped them learn course subjects better. In addition, the main positive learning outcome stated by PST is the acquisition of teaching skills and planning abilities in a differentiated classroom environment. All in all, it can be concluded that, differentiated instruction seemed to contribute to PST’ planning skills and learning of course content.

References Boelens, R., Voet, M., & De Wever, B. (2018). The design of blended learning in response to studentdiversity in higher education: Instructors’ views and use of differentiated instruction in blendedlearning. Computers & Education, 120, 197–212.http://doi.org/10.1016/j.compedu.2018.02.009 Creswell, J. W. (2012). Educational research: Planning, conducting, and evaluating quantitative andqualitative research. Boston: Pearson Dosch, M., & Zidon, M. (2014). The course fits us: Differentiated instruction in the college classroom.International Journal of Teaching and Learning in Higher Education, 26, 343-357. Danley, A. & Williams, C. (2020). Choice in learning: Differentiating instruction in the collegeclassroom. InSight: A Journal of Scholarly Teaching, 15, 83-104.http://dx.doi.org/10.46504/15202005da Field, A. P. (2009). Discovering statistics using spss. (3th Ed.). London: SAGE Publications. Fraenkel, J. R. & Wallen, N. E. (2009). How to design and evaluate research in education (7th ed.).New York: McGraw Hill. Joseph, S., Thomas, M., Simonette, G., & Ramsook, L. (2013). The impact of differentiated instructionin a teacher education setting: Successes and challenges. International Journal of HigherEducation, 2(3), 28-40. Kamarulzaman, M. H., Md-Yunus, M., Azman, H., Mohd-Zahidi, A., (2021). The practice of onlinedifferentiated instruction and its impact on motivation and academic performance in the wakeof covid-19. Preprints, http://doi.org/10.20944/preprints202106.0028.v1 Kokkinos, T. (2020). Aspects of differentiation in teacher education: Exploring student teachers’experiences. African Educational Research Journal, 8(4), 814-821.http://doi.org/10.30918/AERJ.84.20.180. Miles, M. B., Huberman, A. M., & Saldaña, J. (2014). Qualitative data analysis: A methods sourcebook(3rd Ed.). United States: SAGE Publications. Onyishi, C. (2022). Blended or differentiated instruction for inclusive education during post-covid19 era: The Need for upgrading school libraries in Nigeria. Library Philosophy and Practice (e-journal). https://digitalcommons.unl.edu/libphilprac/6979 Santangelo, T., & Tomlinson, C. (2009). The application of differentiated instruction in post-secondaryenvironments: Benefits, challenges, and future directions. International Journal of Teachingand Learning in Higher Education, 20(3), 307-323. Tomlinson, C. A. (2001). How to differentiate instruction in mixed-ability classrooms (2nd ed.).Alexandria, VA: Association for Supervision and Curriculum Development. Tomlinson, C. A., & Imbeau, M. B. (2010). Leading and managing a differentiated classroom.Alexandria, Virginia: ASCD. Wan, S. W.-Y. (2015). Differentiated instruction: Hong Kong prospective teachers’ teaching efficacyand beliefs. Teachers and Teaching, 22(2), 148-176. http://doi.org/10.1080/13540602.2015.1055435 Welch, A. G., Cakir, M., Peterson, C. M., & Ray, C. M. (2012). A cross-cultural validation of thetechnology-rich outcomes-focused learning environment inventory (troflei) in Turkey and theUSA. Research in Science & Technological Education, 30(1), 49-63.http://doi.org/10.1080/02635143.2012.659179