Educational videos offer an engaging and accessible way for preschool children to learn, but their effectiveness can be influenced by several factors, including the quality of the audio and video components, as well as the screen size of the displaying device. While e-books and mobile applications have shown that different screen sizes can lead to different levels of engagement, it is unclear whether this is the case for educational videos. To address this gap, we conducted a study with 124 Portuguese preschool children to investigate whether screen size affects their engagement and learning outcomes when watching educational videos. Our results revealed that screen size did not significantly influence either engagement or learning outcomes. However, we did find a positive correlation between engagement and learning outcomes, indicating that producers should prioritize maximizing engagement levels in their videos. Our study highlights the importance of focusing on engagement as a means to enhance preschool children's learning from educational videos. By understanding the relationship between screen size, engagement, and learning outcomes, producers can optimize their video content to provide an engaging and effective learning experience for young children.