## 4 Discussion
### Limitations, Practical Implications, and Future Work  
One key issue identified by participants was unequal access to reliable internet connectivity, though this problem manifested differently across the two activities. The digital news activity required the use of laptops or tablets, which depended more heavily on stable Wi-Fi connections. Participants reported that connectivity problems hindered their ability to access resources, navigate digital news platforms, or complete the activity efficiently. In contrast, the TikTok-based activity was less affected by these issues, as students primarily used their smartphones, which often rely on mobile data. This suggests that smartphone-based microlearning tasks may offer a more accessible and flexible alternative, especially in settings with uneven digital infrastructure.  
To address such disparities in future implementations, educators should continue to prioritize mobile-friendly formats and explore offline or pre-downloadable resources--especially for activities involving digital news--to ensure that all students can participate equitably regardless of their connectivity conditions. Moreover, as part of future research, it would be valuable to investigate the impact of these learning activities on academic performance through experimental designs that incorporate control groups. Such studies could provide robust evidence regarding the effectiveness of social media-based microlearning in enhancing conceptual understanding and long-term knowledge retention.  
Regarding the survey, a methodological limitation also arose in the evaluation instrument. The item assessing \"the duration of the course in relation to its objectives and content\" yielded a low squared multiple correlation (SMC = 0.169), indicating a weak relationship with the overall satisfaction construct. Its removal modestly improved the internal consistency of the scale (\(\alpha\) increased from 0.68 to 0.70). We attribute this to the multidimensional phrasing of the item, which may have led to participant confusion. For future iterations, we recommend splitting this into two distinct statements--\"The course duration was adequate\" and \"The objectives and content were well-balanced\"--to improve both conceptual clarity and psychometric robustness.  
Finally, while the integration of digital media--particularly TikTok--into science teacher education proved effective in enhancing engagement, several limitations emerged that warrant consideration for future implementations. For instance, privacy and data security emerged as critical considerations in the use of TikTok as an educational tool. Public TikTok accounts allow for wide dissemination and audience reach but pose risks related to unauthorized content sharing and personal exposure [76]. Conversely, private accounts limit those risks but restrict collaboration, which is a key pedagogical affordance of the platform. This duality underlines the need for institutional guidelines and digital literacy training to help pre-service teachers navigate privacy settings, content permissions, and ethical content creation within educational environments. It is also essential that activities involving social media align with institutional policies on data protection and student privacy.  
While the present study centred on chemistry, future research should examine how micro- and nanolearning strategies can be effectively adapted and applied across other Applied Science disciplines, particularly those that pose distinct conceptual challenges and require diverse representational approaches.