The effect that causes the bending of light and sound waves when they enter a different medium is known as refraction. This phenomenon occurs due to the change in speed of the waves as they pass from one medium to another, such as air to water. In optics, refraction is crucial for the design of lenses, which focuses light for various applications like glasses and cameras. Similarly, in acoustics, refraction affects how sound travels in different environments, impacting its clarity and direction.