posted by Mike .
When the rearview mirror in a car is tilted slightly upward to the "nighttime" position, glare is directed upward toward the ceiling, away from the driver's eyes. Yet, the driver can still see cars behind in the mirror. Explain.
The dimmer reflected image comes from an uncoated surface of the glass. The front and back surfaces are not parallel, so two images of whatever is behind the car are sent in two different directions.