## Conceptual Physics (12th Edition)

This is illustrated in Figure 28.38. The critical angle for water is $48^{\circ}$. When a fish looks upward at $45^{\circ}$, which is less than the critical angle, it sees the sky and some reflection from the pond's bottom. If it were to look at an angle greater than $48^{\circ}$ from the normal, it would only see the pond's bottom due to total internal reflection.