* A loud noise: The sound waves hitting your eardrums are an external stimulus that triggers a sensory response.

* The smell of freshly baked cookies: The molecules from the cookies wafting through the air stimulate your olfactory receptors, causing you to perceive the smell.

* A cold shower: The change in temperature from the water against your skin is an external stimulus that activates your temperature receptors.

* The feeling of a hug: The pressure of someone embracing you is an external stimulus that activates your touch receptors.

* A bright light: The photons of light entering your eyes stimulate your photoreceptor cells, allowing you to see.

These are just a few examples. Anything that originates outside of your body and interacts with your senses can be considered an external stimulus.