Final answer:
Objects in water appear shallower due to refraction, and people can sustain injuries when diving into shallow water.
Step-by-step explanation:
When an object is submerged in water, it appears at a shallower depth than it actually is because of the phenomenon called refraction. Refraction occurs when light passes from one medium to another, causing it to change direction. In this case, as light passes from air into water, it bends and changes its path. This change in path makes the object appear closer to the surface than its actual depth.
People sometimes sustain neck and spinal injuries when diving into unfamiliar ponds or waters because they may not take into account the depth of the water. Diving into shallow water can cause the head and neck to hit the bottom forcefully, leading to injuries. It is important to always check the depth of the water before diving and ensure that it is safe.