Blind-Spot Disappearing Dot

A visible mark disappears at a specific distance. Ask students to predict what will happen. Close one eye and move card slowly until one mark vanishes. Key idea: The optic nerve leaves the retina at a spot with no light receptors. Ask: Where did the dot go? Safety and cleanup: No special safety concerns. https://www.google.com/search?q=%22Blind-Spot%20Disappearing%20Dot%22%20science%20demonstration%20experiment