The results of summative assessment and practical work testify to the insufficient level of formation of research skills among 12th grade students. A low percentage of completion was observed in those tasks where it was necessary to provide reasonable conclusions and alternative solutions based on the interpretation and evaluation of the data. This problem determined the purpose  of this experimental study is to evaluate the effect of intensive  practical lessons on students’ educational achievements in exams in physics and biology.This study was conducted among 12^th grade students in the  intellectual schools of Mangystau region, Kazakhstan. The study involved 27 students .  The students were  taught using the system,consisting of three types of practical lessons: a laboratory workshop, a workshop on the study of physical processes based on computer simulation, and a workshop on problem solving.All three types of practical lessons are built on the basis of the scientific method of understanding nature. Lessons-workshops are united by a single structure, scheme, scientific method of cognition, educational and research activities.

Research in education has shown that integrating theory with experiment has many benefits, including developing research skills and understanding of scientific concepts and theories (Fadzil & Saat, 2013; Schwichow, Zimmerman, Croker & Härtig, 2016).

The following research questions were selected for the study:

• How the application of practical lessons affected the student's ability to provide scientific explanations for phenomena, systems and relationship?
• Is there a significant difference between the academic achievements of students who taught  through practical lessons before and after the implementation

The study used a quasi-experimental design before and after testing using quantitative approaches and the plan-do-learn-act PDSA action research model. For a period of seven weeks, the control group students (27students) were taught using the intensive practical method in the laboratory. In this experimental study, the independent variable was the practical work undertaken by students in the school’s laboratory, and the dependent variable was the academic attainment of the participants. To measure the dependent variable, a test was administered prior to participating in the scientific practical activities (pre-test), and after the completion of the activities (post-test). Then a comparison between the pre-test and post-test scores was done to assess the effectiveness of the intervention (practical activities).

The results of students' work showed a significant difference between the academic performance of students who taught science using practical activities. So 98% of students received a high mark on the test results. This indicates an increase in numerical indicators by 43%. The results of our study shows that the integration of science through experiment has a positive effect on students academic achievement.

Abdi, A. (2014). The Effect of Inquiry-based Learning Method on Students’ Academic Achievement in Science Course. Universal Journal of Educational Research, [Online] 2(1), 37-41. Available from: https://doi.org/10.13189/ujer.2014.020104 (Accessed: 15 March 2019). Abrahams, I., & Millar, R. (2008). Does practical work really work? A study of the effectiveness of practical work as a teaching and learning method in school science. International Journal of Science Education, 30(14), 1945-1969. https://doi.org/10.1080/09500690701749305 -212- Journal of Technology and Science Education – https://doi.org/10.3926/jotse.888 Anderson, H.M (n.d). Dale’s Cone of Experience [Online]. Available from: http://www.queensu.ca/teachingandlearning/modules/active/documents/Dales_Cone_of_Experience_summary. pdf (Accessed: 15th March 2019). Aydogdu, C. (2015). Science and technology teachers’ views about the causes of laboratory accidents. International Journal of Progressive Education, 11(3), 106-120. Birk, J.P., & Foster, J. (1993). The importance of lecture in general chemistry course performance. Journal of Chemical Education, 70, 180-182. https://doi.org/10.1021/ed070p180 Boyuk, U., Demir, S., & Erol, M. (2010). Analyzing the proficiency views of science and Technology teachers on laboratory studies in terms of different variables. TUBAV Bilim Dergisi, 3(4),. 342-349. Brooks, J.G., & Brooks, M. (1999). In Search of Understanding: The Case for Constructivist.