What does SPF stand for in relation to sunscreen's effectiveness?

The correct answer, which is "Sun Protection Factor," refers to a measurement of how effective a sunscreen is at protecting the skin from UV radiation, particularly UVB rays, which are the main cause of sunburn and can contribute to skin cancer. The SPF rating indicates the level of protection offered; for example, a sunscreen with SPF 30 theoretically allows a person to stay in the sun 30 times longer than they would without protection before getting sunburned, assuming proper application.

Sunscreen labeled with higher SPF values typically provides more protection against UVB rays, but it’s essential to apply it correctly and reapply as recommended, regardless of the SPF number. This is why understanding the meaning of SPF is crucial for effective sun safety and skin care.