How do you tell if sunglasses are made of glass?

Bagis:

Hit them very hard with a hammer.

Nearly all glasses are now made out of plastic, even ones made with custom lenses, it’s easier, cheaper to manufacture, and actually can be more accurate than a glass lens.

Also, it’s safer if you get hit in the face!

Samrtyfox:

Tap on one of the lens with your finger nail. if it’s glass it’ll sound like glass. if it doesn’t sound like glass then it isn’t glass. if you don’t know what it sounds like when you tap on glass get a glass jar or something else glass and tap on it.

Paul D:

Slightly less destructive than a hammer is checking by temperature — Glass holds its temperature more.

Compare the feel of anything in a glass jar the fridge to something in plastic. Glass feels cooler than plastic. Or hotter if just out of the dish washer. If you touch a piece of plastic to your cheek it will usually feel room temperature, whereas if you do the same with a piece of room temperature glass it will usually feel somewhat cold.

Also these days they don’t drill holes in glass lenses to attach frames anymore, so if they have a hole to hold the lenses in place then they are plastic. (Unless they were made before the 1980’s) Another way to tell the difference between glass & plastic is to tap it with your teeth…