Chemical substances affect our senses differently due to the distinct nature of light and sound waves. Light is an electromagnetic wave that interacts with photoreceptors in our eyes, allowing us to see, while sound is a mechanical wave that requires different receptors in our ears to perceive. The discussion highlights that humans and some animals can form mental images of their surroundings using auditory cues, a skill that can be enhanced through training, such as echolocation. Additionally, the conversation touches on the role of chemical senses in perceiving the environment, emphasizing that different organisms have evolved various sensory mechanisms to interpret information. Understanding these differences is crucial for appreciating how we and other species experience the world.