Grand Award

Second Place

Which Glass Type Blocks the Most Light?

Physics and Astronomy
Emile Leslie

Elyse Wexler

Every year, car crashes are a leading cause of death and injury worldwide, many of which are caused by sun glare, a phenomenon which is caused by intense light and limits eyesight. This especially affects the elderly and people with medical issues. This experiment was conducted to ask how much light different types of glasses block, something that could help prevent sun glare. This was achieved by, rather than trying to create a new glass to block as much light, trying to see what existing in-use glass types blocked light. A set of experiments were conducted with a mirror redirecting light through glass to a light meter and measuring the light levels and comparing the number to the outside light levels using subtraction. These revealed that crooks glass blocked the most light singularly, crooks and tempered glass blocked the most light as a combo, and CR-39 glass blocked the least light and rather amplified light levels. Uncovered with no glass, there was a loss of about 12,100 lux in redirection, which was compared to the blocking of light by crooks' glass (~ 27,200lux), crooks' glass and tempered glass (~ 28,500lux), and CR-39 glass (~ 200lux). Crooks glass is commonly used in sunglasses, and thus worked best due to its purpose, while CR-39 glass likely focused the light further. This helps show how to best avoid sun glare to avoid accidents, and the effects of sun glare on the vision impaired, as CR-39 glass is the type used in prescription glasses.

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