Light reflects and refracts when it hits glass due to its dual nature, described by both classical and quantum physics. Classical explanations focus on the change in speed and direction of light as it enters a different medium, while quantum explanations involve the interaction of photons with the atomic structure of glass. The phenomenon occurs simultaneously because some light is transmitted through the glass while some is reflected back. For a deeper understanding, resources like Feynman's "QED: The Strange Theory of Light and Matter" are recommended. Engaging in personal research can also enhance comprehension of these concepts.