Week 30: My mom's glasses

You know that irritating thing when you're wearing glasses and someone takes a picture of you so the camera flash causes this unsightly white spot on one or both of your lenses? I hate that.


My mom doesn't know that feeling because her glasses have an anti-reflective coating on them. This thin coating on the glass has a different index of refraction compared to the air above it and the glass below it. It decreases the amount of light reflected off of the surface. There is a wide spectrum of corrective lenses our there and sometimes, the thicknesses of the thin films may vary, or the indices of refraction could be different for multiple-layered lenses. However, these can change in order to cause destructive interference in the lens and lessen the burden on the eye.


Unfortunately, I do not have  picture of my mom's real glasses tonight but I do have this picture. 

She never has to worry about getting that unsightly white blot in her pictures. I, however, am not so lucky.


And, voila, the Physics of my mom's sunglasses.