Submicroscopic Level Research Articles

A Review of Research on Learning Activities Addressing the Submicroscopic Level in Chemistry

A Review of Research on Learning Activities Addressing the Submicroscopic Level in Chemistry

Microscopic and submicroscopic exploration of diplolepideae peristome structures in hygroscopic movement

BackgroundThe Diplolepideae are the larger group within the Arthrodontae mosses, characterized by peristomes formed from residual cell walls. It is now understood that these peristomes exhibit diverse hygroscopic movements, playing a crucial role in spore release. However, the exact mechanism behind this movement remains unclear, lacking direct evidence. This study investigated the microscopic and submicroscopic structures of the peristomes in three Diplolepideae species: Hypopterygium fauriei (Besch.), Pylaisia levieri (Müll. Hal.) Arikawa and Regmatodon declinatus (Hook.) Brid. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to reveal the differences in their hygroscopic movement mechanisms.ResultsThe three species exhibited distinct responses upon wetting: H. fauriei’s exostome closed inwards, P. levieri’ opened outwards, and R. declinatus’ elongated significantly. These differences are attributed to the varying microfibril deposition in the exostome layers. Uniform deposition in the inner layer and minimal deposition in the outer layer enabled exostome opening upon wetting and closing when dry. Our findings suggest that the diastole and contraction of fine microfibrils in the exostome plates and ridges are the key drivers of hygroscopic movement.ConclusionsThis study provides further evidence at both the structural and submicroscopic levels, contributing to the unraveling of the hygroscopic movement mechanism in Diplolepideae peristomes. This enhanced understanding sheds light on the relationship between peristome structure and function.

Description of Students' Multirepresentation Ability on Hydrocarbon Material at SMA Negeri 1 Sungai Kunyit

Material in chemistry learning will be easier to understand if students are able to represent it at three levels of representation, namely macroscopic, sub-microscopic and symbolic. This research aims to describe students' abilities in using various representations in class XI MIPA 1 hydrocarbon material at SMA Negeri 1 Sungai Kunyit. Students' thinking processes require various representations and various ways or steps to solve problems. The type of research used is quantitative descriptive research. The research instruments used included 9 two tier multiple choice objective test questions and an interview guide. This research involved 20 students of class XI MIPA 1 SMA Negeri 1 Sungai Kunyit. The research results show that overall, the average multi-representation ability of students is 29% in the poor category. At the macroscopic representation level, the average percentage obtained is 20% which can be classified as very poor. At the sub-microscopic level of representation, the average is 35% which is included in the poor category. Finally, at the level of symbolic representation the average percentage is 31% which is also included in the poor category.

Augmented reality for chemistry education to promote the use of chemical terminology in teacher training.

Chemistry as a whole is divided into three levels. The macroscopic level describes real, observable phenomena of the material world. The submicroscopic level focuses on particles. The representative level includes pictorial and symbolic representations to visualize substance in its nature. Students often have problems separating these levels and conceptually transfer each of the three levels to the other. Therefore, teachers need to use chemical terminology correctly when teaching the substance-particle concept. Augmented Reality (AR) connects real and virtual world. The observer physically moves in a real environment that integrates virtual elements. The AR technology has great potential for learning in the subject chemistry, especially when it comes to making the "invisible" visible and illustrating scientific phenomena at particle level. The simultaneous presentation should avoid split-attention and offers new possibilities to interactively deal with (M)ER. The question arises whether AR has a positive effect on the use of technical language and the associated understanding of the concept of dealing with (M)ER at the substance and particle levels. With an AR app on the tablet and the AR glasses, the chemical processes of a real experiment are represented by AR visualizations. Therefore, the AR app was piloted. This study captured the chemistry handling with (M)ER of chemistry teachers (N = 30) using a pre-post survey. The participating preservice teachers are described below. Each test includes five tasks elaborated by thinking aloud. The thinking-aloud protocols to acquire the use of the chemical terminology are evaluated in MAXQDA.

Multiple Representations Analysis of Chemical Bonding Concepts in General Chemistry Books

This research aimed to analyze the use of the concept of the three levels of chemical representation in eight general chemistry books. It was qualitative research with an evaluative descriptive design. The concepts analyzed included the concepts of ionic, covalent, and metallic bonds. The analysis focused on two main criteria: the use of macroscopic, sub-microscopic, and symbolic levels of representation and the relationship between the three levels. The results of the analysis showed that in the concept of ionic bonding, there were pictures of some salts or reactions for the formation of ionic compounds from their elements at the macroscopic level, explanations at the sub-microscopic level, and models of the arrangement of ions in the ionic crystal lattice for the symbolic level. In the concept of covalent bonds, there were images of gasses or covalent compounds at the macroscopic level, explanations at the sub-microscopic level, and models of electron density shifts at the symbolic level. In the concept of metallic bonds, there were pictures of some metals at the macroscopic level, explanations at the sub-microscopic level, and electron cloud models at the symbolic level. The relationship between the levels of representation was found in five of the eight general chemistry books analyzed. General chemistry books present the relationship between the three levels of representation in images that include energy level diagrams, atomic or ionic arrangement models, reaction equations, and explanations of the molecular level.
 Keywords: concept, chemical representation, general chemistry, books

Development and Validation of a Virtual Test Based on Three Level Chemical Representation to Measure Student Understanding of Hydrolysis of Salt

This study aimed to develop and validate virtual tests based on three levels of chemical representation that can measure students’ understanding of salt hydrolysis. This study used development and validation methods, which consisted of 4 phases. First, the determination of the purpose and the scope of the test. Second, the development and design of the test Third. The validation, selection of items and scoring guidelines. Lastly, the assembly and evaluation of the test. The instruments used were a content validation sheet for experts to judge and an interview sheet for students. The participants were 11th grade senior high school students from three different schools in Karawang with 60 total respondents, and six of them were interviewed. The results showed that the virtual test containing 33 multiple choice items was valid with the Content Validity Index (CVI) value for macroscopic, submicroscopic, and symbolic level items being 1. The Virtual test was also reliable, with Cronbach’s alpha value for macroscopic, submicroscopic, and symbolic level items, respectively, being 0.605, 0.614 and 0.644. The results of this research can be used to measure students’ understanding of hydrolysis of salt based on three-level chemical representation.
 Keywords: virtual tests, chemical representation, salt hydrolysis

Evaluation of surface pretreatment methods on thin austenitic stainless steel foils for adhesive bonding applications

ABSTRACT Stainless steel is used across all industries, from the chemical or construction sector to household appliances. To produce load bearing joints, a surface treatment of the passive surface of austenitic stainless steel is generally necessary. However, the treatment of thin-walled foil materials inhibits challenges concerning the deformation under thermal loads. This work investigates the effectiveness and mechanisms of different surface treatments on 50 µm thin AISI 316 L steel foil. Basic cleaning, surface finishing with an aluminum oxide abrasive, flame-pyrolytic deposition of silicon dioxide and application of a primer, etching with hydrochloric acid, treatment by atmospheric plasma, ns-pulsed laser surface cleaning, and fs-laser structuring are investigated. The effects of these treatments are analyzed in surface energy investigations by contact angle measurement, roughness measurements, and SEM-EDX. The bonding strength is tested with epoxy adhesives and a methyl methacrylate adhesive under 90° peel load. The failure mechanisms are further investigated by FTIR spectroscopy and SEM-EDX. The results show that the used coating with primer produces the strongest bonds, followed by the fs-laser treatment. In particular, sub-microscopic surface structures induced by fs-laser show promising results. SEM images show a full wetting of the capillary structures, providing the possibility of mechanical interlocking on a sub-microscopic level.

Features of immune reactivity of the spleen and mechanisms of organ damage under the influence of animal venom toxins including scorpions (review).

Aim: To establish features of immune reactivity of the spleen and mechanisms of organ damage under the influence of animal venom toxins including scorpions. Materials and Methods: A thorough literature analysis was conducted on the basis of PubMed, Google Scholar, Web of Science, and Scopus databases. When processing the search results, we chose the newest publications up to 5 years old or the most thorough publications that vividly described the essence of our topic. Conclusions: Spleen plays a leading role in the implementation of the body's defense processes, the elimination of structural elements affected by toxins, and the restoration of immune homeostasis. Its participation in the formation of the immune response can be accompanied by qualitative and quantitative changes in histological organization. Morpho-functional changes in the spleen under the action of animal venom toxins currently require careful study, because from the information available in the literature today, it is not possible to clearly construct a complete picture of lesions of certain components of the organ at the microscopic or submicroscopic levels. Therefore, this direction of research in the medical field is currently relevant, taking into account the existence of a large number of poisonous animals, including scorpions.

SUBMICROSCOPIC CHANGES OF RAT’S CEREBRAL CORTEX IN TERMS OF DMG-INDUCED EXPERIMENTAL ONCOGENESIS AND UNDER CONDITIONS OF NANOMATERIALS APPLICATION

Abstract. Expansion and enhancement of research on colorectal cancer, particularly its impact on the cerebral cortex, stand as a profoundly critical task for the scientifi c community.The objective of this study was to identify submicroscopic alterations occurring in the brain cortex during the development of experimental colorectal cancer. Additionally, the article examines the potential application of nanoparticles in the context of colorectal cancer treatment. Animals were divided into three groups: Group I consisted of 35 intact animals, Group II had 70 animals with DMH-induced carcinogenesis, and Group III included 20 animals with neoplastic lesions receiving a composition of Au/Ag/Fe nanoparticles. Experimental carcinogenesis was induced using N, N-dimethylhydrazine hydrochloride, administered once a week for 30 weeks. Animals in Group III were given an intra- gastric dispersion of Au/Ag/Fe nanoparticles once daily for 21 days. Histological preparations were made using conventional methods. Examination of the specimens was conducted using the PEM-125K electron microscope.Results. The utilization of Au/Ag/Fe nanoparticles facilitated the restoration of structural elements within the cerebral cortex at a submicroscopic level compared to animals subjected to DMH-induced carcinogenesis. The application of nanoparticle composition contributed to the restoration of structural elements in the cerebral hemisphere, reduction in alternative changes in neurocytes, and regeneration of damaged blood capillaries in the organ.Conclusion. Drawn from the study’s outcomes indicate the eff ectiveness of applying Au/Ag/Fe nanoparticles in mitigating the adverse eff ects of the development and progression of DMH-induced adenocarcinoma in situ on the cerebral cortex.

Don’t we know enough about models? Integrating a replication study into an introductory chemistry course in higher education

Abstract This paper presents the German translation and replication of the Students’ Understanding of Models in Science (SUMS) instrument, aiming to assess how first-semester university students comprehend the submicroscopic level in chemistry courses. The assessment of students’ understanding is a prerequisite for improving teaching practices, particularly in addressing the persistently high drop-out rates observed in chemistry and chemistry-related programs. Employing a quantitative methodology, a sample of 181 undergraduate chemistry students was surveyed. The data were analyzed using structural equation modeling, resulting in two statistical models that demonstrated an excellent fit to the data, although no empirical preference could be established for one model over the other. Based on the investigation, framing models as exact replicas of the natural world cannot be considered an empirically meaningful dimension of understanding models in science. Additionally, the reliabilities of the latent constructs were found to be insufficiently low to establish generalizable measurements. These findings are discussed with a focus on epistemology and advocate for a stronger integration of model theory in chemistry teaching and learning. Finally, the importance of establishing a stronger connection between empirical evidence and the implementation of curricular changes in higher education is emphasized.

What makes representations good representations for science education? A teacher-oriented summary of significant findings and a practical guideline for the transfer into teaching

Abstract Existing instructional materials for chemistry offer a huge range of different external representations that can be used by chemistry teachers to support students’ understanding of chemical concepts like the concept structure of matter. In science, different kinds of representations are usually combined forming multiple external representations. Examples are combinations of texts, pictures, figures, diagrams, graphs, tables, schemes etc. However, these multiple external representations often have problematic features and/or do not meet students’ subject-related learning needs. For example, many external representations do not take different representational levels into account and/or mix information on the macroscopic level with those from the submicroscopic level. Such representations have the potential to favor students’ misconceptions who often struggle with separating different representational levels. Therefore, it is important to highlight crucial characteristics of external representations that potentially facilitate students’ learning of chemical concepts at lower secondary schools (age group 10–14). When chemistry teachers consider and reflect crucial characteristics of representations and adapt existing external representations or develop new ones, these new representations can become powerful cognitive tools helping to make instruction in chemistry more effective and coherent. This article answers the question What makes representations good representations in science education? by describing features of effective learning with decisive characteristics of multiple external representations and highlighting these characteristics by means of concrete examples from chemistry learning. Finally, an online tool will be outlined that can help teachers to improve multiple external representations for use in chemistry classes.

Development of Test Instruments to Test Students' Understanding of Macroscopic, Sub-Microscopic and Symbolic Levels in Acid-Base Titration Material Using the Rasch Model

This study created a test instrument that can test students' understanding of the macroscopic, sub-microscopic and symbolic levels in acid-base titration material that has been tested for validity, reliability, difficulty index and differential power of the questions . This development research uses the Rasch model. The subjects of this study were four lecturers, two high school chemistry teachers and 35 students of SMA N 2 Padang. The object is the quality of the test instrument that meets the criteria of validity, reliability, difficulty index and discriminatory power . Data analysis used the MiniFac and Ministep programs. This study has 10 stages, namely: (1) Defining the construct, (2) Identifying the construct, (3) Designing the items, (4) Testing the product, (5) Analyzing the data, (6) Reviewing the results of the analysis, (7) Reviewing the map wright, (8) Repeat steps 4-7, (9) Claim product quality, (10) Develop documentation. The results showed that the suitability of validation by experts using the MiniFac program was the exact agreement and expected agreement values were very close, namely 95.8% and 95.4%, this indicated that the results of this analysis fit the model and its estimation. Likewise testing of students using the Ministep program. Each item can be said to be valid because it meets the criteria of the MNSQ, ZSTD and PtMean Corr. The instrument is also claimed to be reliable because it has a value of 0.92 . The difficulty index and discriminating power of the items also varied from the easiest to the most difficult.

Development of Test Instrument to Assess Students' Understanding on Macroscopic, Sub-Microscopic, and Symbolic Levels of Acid-Base Topics Using Rasch Model

Students' conceptual understanding on acid-base topic has not been assessed comprehensively in multiple representation. The test instrument is needed to determine levels of students' understanding on acid-base topic comprehensively. This research developed an instrument to asses students' understanding on acid-base concept based on macroscopic, sub-microscopic and symbolic levels that is claimed valid, reliable, had good difficulty index and discriminatory item. This research is Research and Development (R&D) using Rasch model. The research procedure adopted ten stages by Wei, et al in 2012. The research instrument is questionnaire sheet given to subjects from chemistry lecturers and chemistry teacher. The data were analyzed using Rasch model assisted by minifacet and ministep software. The exact agreement value is 89,2% which have small range from the expect agreement with a percentage of 89,5%. It’s mean that, there is a fit between the results of expert's agreement and the results of estimated model. The pilot test results showed that all items have reached valid criteria based on the MNSQ, ZSTD, and Pt-Mean Corr. The reliability value is 0,80 in the good category. Difficulty index has variations of easy, medium, and difficult items. The discriminatory item is able to distinguish three levels of student ability.

Identifying Chemistry Students' Baseline Systems Thinking Skills When Constructing System Maps for a Topic on Climate Change.

New resources have recently been emerging for educators to implement systems thinking (ST) in chemistry education, including a proposed set of ST skills. While these efforts aim to make ST implementation easier, little is known about how to assess these skills in a chemistry context. In this study, we investigated ST skills employed by students who constructed system maps of a topic related to climate change. Eighteen undergraduate chemistry students from first- to third-year participated in this study. We designed and implemented a ST intervention to capture how students engaged with three ST tasks, performed individually and collaboratively. In our analysis, we focused on 11 ST skills that aligned with five characteristics proposed in a recent study. We found that participants demonstrated most of these ST skills when engaging with the ST tasks, with nuances. Participants' system maps: (1) lacked concepts and connections at the submicroscopic level, (2) included multiple types of connections but few circular loops and causal connections, (3) lacked causal reasoning, although participants did predict how their system maps changed over time, (4) demonstrated the breadth of connections but did not describe human connections to the underlying chemistry of climate change topics. These findings identify aspects of ST where chemistry educators need to place emphasis when teaching ST skills to chemistry students and when guiding learning activities and other assessments. Using our findings, we created an adaptable ST rubric for the chemistry community as a tool for assessing ST skills.

Development of an assessment instrument to evaluate the concepts of chemical equilibrium at macroscopic, sub-microscopic, and symbolic representation levels using the rasch model

This study aims to develop a test instrument that can be used to evaluate the concept of chemical equilibrium at the macroscopic, submicroscopic, and symbolic levels of high school students who are declared valid, reliable, have a difficulty index, and have good item discrimination. This study was designed using the Rasch development model, which Wei has modified with ten research stages. The results of the research to test content validity were analyzed through the minifacets program with five validators consisting of four chemistry lecturers at Padang State University and one teacher at high school SMAN 3 Padang, obtaining fit analysis results seen from the exact agreement value of 89.1%, which is very close to the expected agreement value of 89.7%. The test results on 30 students of SMAN 3 Padang who were analyzed through the ministep program showed valid results for all items because they met the criteria for the MNSQ, ZSTD, and Pt Mean Corr outfit scores. The reliability value obtained for the item is 0.74, which meets the sufficient criteria, and Cronbach's alpha reliability value is 0.74, which meets the good criteria. All question items also do not have DIF based on gender. The analyzed index of difficulty and discriminating power fulfilled the good criteria with the classification of easy, medium, and difficult items.

The Chemistry Triangle-Based Multimedia to Build A Good Impression: A Design-Based Research

<p>Science teachers need to pay attention when introducing chemistry to junior high school students hence they don't have low perceptions of chemistry. Multimedia which based on the chemistry triangle can be a solution in helping teachers explains the relationships among macroscopic, sub-microscopic, and symbolic level of chemistry so students can understand the scientific contents better and have a good perceptions. This research aimed to develop a chemistry triangle-based multimedia to build a good impression on junior high school students about chemistry. The design of chemistry triangle-based multimedia was developed through a design-based research (DBR). The participants in the research were three schools of seventh-grade students in Pekalongan Regency, Indonesia. The data were collected through interviews, observations, questionnaires, and tests. The results of this research were in the form of the complete cycles of DBR carried out to produce a chemistry triangle-based multimedia that meets the criteria in helping teachers introduce chemistry in a way that is more easily accepted by students and gives a positive impression about chemistry. This article describes the four phases of the DBR process in the development of chemistry triangle-based multimedia.</p><p> </p>

Das werden-Passiv in Schulbüchern der Chemie

Abstract The competent use of the specific language of school subjects is fundamental for successful learning and teaching in school. For a language-sensitive design of lessons and empirical foundation of didactic and methodical concepts, knowledge of how students read a text is needed as well as evidence-based knowledge of formal and functional aspects of subject-specific language. A corpus analysis confirms that the passive is a prototypical construction in chemistry textbooks. Thus the competent handling of those sentences is a relevant aspect of subject-specific language competence. The verbs used in the passive sentences in books included in the corpus are predominantly morphologically complex, and can be indicated as chemistry-specific lexis, e. g. related to the sub-microscopic level. Furthermore, they are commonly used in conjunction with abstract agents. On the other hand, these verbs are also encountered to students in everyday (i. e. non-subject-specific) contexts but in these contexts they diverge semantically and are commonly used in conjunction with a human agent. Therefore, the function of the passive sentences differs: While passive sentences with a human agent allow an expression of anonymised actions, the passive sentences with abstract agents enable the verbalisation of abstract processes. The distribution of those functional distinction differs between school subjects and contexts. Abstract agents in passive sentences can support the maintenance of pre-instructional concepts of students, especially if the verbs are not obviously specific for the context of chemistry. Therefore, a specific language-education for school subjects is needed which includes the analysis of formal and functional aspects. The results of the corpus analysis can be used for context-based scaffolding in language-sensitive chemistry lessons.

From Symbolic Representation to Submicroscopic One: Preservice Science Teachers’ Struggle with Chemical Representation Levels in Chemistry

Being able to move between different representations levels (macroscopic, sub-microscopic, and symbolic) is important to understand a chemical phenomenon meaningfully. The current study investigated how pre-service science teachers moved from symbolic representation to sub-microscopic representation. A total of 205 pre-service science teachers, first, balanced the three chemical reactions and then drew the reactions’ sub-microscopic views if they were able to observe them. The findings revealed that pre-service science teachers are most successful at the symbolic level. Yet, this is not a valid conclusion for the sub-microscopic representation level. The drawings were analyzed concerning atomic size and molecular geometry and found that pre-service science teachers have common alternative concepts. Furthermore, they mostly have a superficial knowledge of the molecular geometry of chemical compounds. In conclusion, because pre-service science teachers will teach in their future careers, it is important to encourage them to comprehend chemical phenomena at each representation level and shift between them to prevent alternative concepts they may have.

A Combination of Real-World Experiments and Augmented Reality When Learning about the States of Wax—An Eye-Tracking Study

Burning candles show the solid and liquid states of wax on a macroscopic level. With augmented reality, the submicroscopic and symbolic level of all three states of wax can be shown. The augmented reality environment developed in this study lets students test their knowledge about the position of the three states of wax. So far, how the design parameters of augmented reality learning environments influence users’ eye movement and learning performance has not been researched. Twenty-three German students between the ages of 9 and 15 form the randomized sample of this study with three different groups. AR learning scenarios were created, varying only in one design parameter: ‘congruence with reality’. Our analysis using audio, video, and eye-tracking data showed that all the participants learned mostly the same and that the participants who saw the real experiment on screen experienced the highest degree of immersion. This study indicates that the presented AR learning environment is an opportunity to learn about what exact part of a candle is burning with the submicroscopic level shown in comparison; before using the learning environment, the students were uncertain about what substance burns when a candle is lit and what function the wick has. This study suggests teachers should think about implementing learning environments such as this to help students connect different levels of representation.

Does Augmented Reality Help to Understand Chemical Phenomena during Hands-On Experiments?–Implications for Cognitive Load and Learning

Chemical phenomena are only observable on a macroscopic level, whereas they are explained by entities on a non-visible level. Students often demonstrate limited ability to link these different levels. Augmented reality (AR) offers the possibility to increase contiguity by embedding virtual models into hands-on experiments. Therefore, this paper presents a pre- and post-test study investigating how learning and cognitive load are influenced by AR during hands-on experiments. Three comparison groups (AR, animation and filmstrip), with a total of N = 104 German secondary school students, conducted and explained two hands-on experiments. Whereas the AR group was allowed to use an AR app showing virtual models of the processes on the submicroscopic level during the experiments, the two other groups were provided with the same dynamic or static models after experimenting. Results indicate no significant learning gain for the AR group in contrast to the two other groups. The perceived intrinsic cognitive load was higher for the AR group in both experiments as well as the extraneous load in the second experiment. It can be concluded that AR could not unleash its theoretically derived potential in the present study.