Evolution after the Revolution: How Classical and Online School Chemistry Teaching Has Changed during the COVID-19 Pandemic?

Two years of the COVID-19 pandemic had a tremendous impact on education. In the beginning, teachers were shocked by compulsory online teaching; later, they had to cope with changing restrictions, distance, and blended and hybrid environments. Such a situation was particularly difficult for chemistry teachers, who not only were forced to find a way to organize classes focused on theoretical knowledge but also had to present various phenomena, reactions, and preferably, practice laboratory skills. This paper is focused on changes in chemistry teaching at the secondary school level after two years of the pandemic compared to the first lockouts. The study involved 28 chemistry teachers and their 110 students, all from Slovakian secondary schools, and was based on online questionnaires. Results revealed how online school chemistry teaching changed, what were the teachers’ challenges and attitudes toward online teaching, and how the students perceived online chemistry lessons. It was found that various groups of teachers mastered elements of online teaching at different levels. There are still teachers who struggle with the basics of online teaching but also skilled teachers who can handle many online teaching features. However, all of them still require assistance in their development, covering methodological, technical, and equipment areas. Therefore, results of this study suggest which aspects of online education instructors should pay attention to during pre- and in-service teachers’ training, so skills gained by teachers during the pandemic will not be lost, and which areas of online teaching are beneficial or difficult for students.


Supporting Information
Chemistry teaching after 2 years of pandemic -teacher's questionnaire Chemistry learning after 2 years of pandemic -student's questionnaire

Results from teachers' questionnaire
Results from students' questionnaire Table S1.Demographic description of teachers participating in the research.Answers for frequency of online classes

Limitations of the study
Chemistry teaching after 2 years of pandemic -teacher's questionnaire Dear colleagues, thank you very much for your time and for completing this questionnaire.This survey is aimed to find out what has changed in your teaching after 2 years of the pandemic.We hope to find not only your strengths but places to improve as well.The results of this questionnaire will be anonymized.Thank you again.
Questions for teachers: 1.Last name (for merging students' and teachers' answers) 2.

Results
Although they agreed that the teacher used more handwriting on the screen (71%), had better access to a computer (62%), and they used more online tools (57%), only half of the students thought that teacher is more confident in online teaching (53%), that they experienced fewer problems during online lessons (51%), or had better access to the Internet (47%).Compared to the beginning of the pandemic, only 40% of students think they were more effective in time management, 36% of students thought they discussed more, 32% of students thought that the experiments were more interesting, and only 21% of students thought that there were more experiments used in online teaching.

Results from teachers' questionnaire
In the next question, teachers were asked: "What is still the biggest challenge in online teaching?"Here, the most interesting answers are presented:  "More time for preparation" (Monika);  "To engage more students" (Celine);  "More online demonstrations, not just videos" (Parvati);  "Use of a graphical tablet" (Nataly);  "Working in groups  I have not done it yet" (Ursula);  "Check the writing of chemical equations live during online lessons" (Hedwige);  "Hybrid lessons" (Olive).Is there anything more about chemistry learning that you would like to share?
 "Learning chemistry during online classes was, at least for me, the most interesting and effective compared to other subjects."(Tamara, 18y)  "Some students did not pay attention in class at all and said they have connection problems or something similar.And the teachers didn't believe the students who really had problems."(Sima, 13y)  "The teacher devoted herself admirably to us.Her lessons were enriched with various interesting and expanding information.The materials she gave us access to were very informative and interesting.All of us who liked the chemistry and biology classes taught by our teacher had the opportunity to consolidate our learning in her classes in order to achieve the best possible results.
And she gave us many practical information for life."(Natalia, 14y)

School
Teacher Name

Limitations of the study
The questionnaires were sent to the teachers in March 2022.At this stage, schools had their own responsibility to manage the COVID-19 situation, and regulations for school closures did differ across the country, therefore, participating teachers and students had various online time load when the research was conducted.The questionnaire was made available in an online form which could limit the likelihood of response in case of some teachers and students.Since the questionnaire was prepared in the Slovak, the responses of the participants were coded by a single researcher.The data analyzed in this research are based on answers from 28 teachers and 110 students.Although the group could have been larger, it represents opinions from the whole country and all regions.This study was carried out in Slovakia which may have its specifics and regional aspects.Despite these limitations, we hope that it would guide and help other educators.

Figure S1 .
Figure S1.The most frequent answers to the question: What is the most acute problem against students' participation in online classes? Figure S2 Change in grades during distance learning -teachers' answers Figure S3.Students´ responses to the question: What they liked the most in distance chemistry learning?Figure S4.The most difficult things for students during distance chemistry Figure S5 Students answers to question: Did distance learning influence your grades in chemistry?Figure S6.Answers of students to the question: Do you like chemical experiments in distance classes?

Figure S1 .
Figure S1.The most frequent answers to the question: What is the most acute problem against students' participation in online classes?

Chemistry learning after 2 years of pandemic -student's questionnaire
What has changed in your online lessons since the beginning of the pandemic?(open question) 6.What would you like to change in your online lessons?(open question) 7. What is still the biggest challenge for your online teaching?(open question) 8. What is the most acute problem in students' participation in online classes?(open question) 9. Compare your current online teaching to the beginning of the pandemic and the first lockout.In the last six months, how often have you been using data loggers during online teaching experiments?-conditional o 1.I never use data loggers o 2. Rarely (I used data loggers once or twice) o 3. Sometimes (I used data loggers a few times) o 4. Often (I used data loggers almost on every second experiment) o 5. Very often (I used data loggers almost at every experiment) 13.What has changed in using experiments in your online teaching?(open question) 14.What do you consider the biggest change in using experiments in your online teaching?(open question) 15.What do you consider the biggest challenge in using experiments in your online teaching?(open question) 16.Have you used hybrid teaching during your onsite lessons?(By hybrid teaching we understand mixing face-to-face classes with part of the group, and other students participating in the classes Could you describe how you organized the hybrid classes?(open question) -conditional 18.How did distance learning affect the grades of your students?(1-5 bipolar, 6 th hard to say) Dear students, thank you very much for your time and for completing this questionnaire.This survey is aimed to find out what has changed in your chemistry lessons after 2 years of the pandemic.The results of this questionnaire are anonymous (you may provide us with your nickname) so please be honest with your answers.Thank you again :-) Grades significantly improved during distance learning o Grades slightly improved during distance learning o Grades remained the same during distance learning o Grades slightly worsened during distance learning o Grades significantly worsened during distance learning o It´s hard to say 15.What do you think about assessment in distance chemistry learning?(open question) 16.How has the pandemic affected your approach to learning?(open question) 17.Is there anything more about chemistry learning you would like to share?(open question)  I play a video of the experiment;  I show the experiments to students through a live demonstration;  Students do the experiments at home;  Some other way: ________ 12. o Grades significantly improved during distance learning o Grades slightly improved during distance learning o Grades remained the same during distance learning o Grades slightly worsened during distance learning o Grades significantly worsened during distance learning

Table S1 .
Demographic description of teachers participating in the research.Answers for frequency of online classes (never, rarelyonly once or twice, sometimesfrom time to time, often -almost every second lesson, very often -almost every lesson).