As you move the piece of paper with the arrow away from the glass of water, the arrow appears to reverse. The light is refracted as it passes through the glass, the water, then through the back of the glass and finally through the air to the paper with the horizontal arrow. This refraction causes the horizontal arrow to appear as if it is reversed.
Connect with the Southeast Missourian Newsroom:
For corrections to this story or other insights for the editor, click here. To submit a letter to the editor, click here. To learn about the Southeast Missourian’s AI Policy, click here.