Open your discussion of sensation and perception by showing students this image. Note the white on the clear bulb where the light is reflecting. Our eyes detect white, but our brains know that those white spots aren’t really white. Based on past experience, our brain perceives the white as merely reflections of light.
Next, show students this photo.
It’s not quite The Dress, but this is still pretty cool. Like many people, what you see are shiny legs. Do they look like they are covered in a hard, clear plastic?
But what if I told you that there is no plastic. It’s just strategically placed white paint?
If you saw shiny legs, you were perceiving the white as reflected light, as you rightly did with the light bulb. Once you’re told the white is paint, the shininess disappears, and you are just left with, well, white paint.