how does sunscreen work?
In: Chemistry
Sunscreen is basically a layer of skin on top of your skin. It either absorbs or reflects the uv away from your skin.
Physical (mineral) sunscreen ingredients (including the minerals titanium dioxide and zinc oxide) block and scatter the rays (like a stealth plane) before they penetrate your skin. Chemical sunscreen ingredients (like avobenzone and octisalate) absorb UV rays (like a sponge) before they can damage your skin.
Light is a broad spectrum, we can only see a very tiny part of it. Most of a sunburn is caused by UV light. Sunscreen is basically an opaque paint for UV light, but clear for visible light. If you look at someone putting on sunscreen using a camera that can see UV light, it looks like they are smearing black paint on. It blocks the UV light from hitting your skin.
It has chemicals in it that absorb UV light, it’s really that simple. You can observe this if you watch someone apply sunscreen through a UV camera, the sunscreen appears black even after they spread it on themselves.
Light is much more than just visible light. In ascending order of energy/frequency
Radio, microwave, infrared, visible light (red, orange, yellow, green, blue, violet), ultraviolet, xrays, gamma rays
Visible light is only a very tiny sliver of what makes up light, and the higher energy light (UV and above) is what’s considered dangerous.
When we look at something that’s red, that means it’s reflecting red light and absorbing the other colors. UV is basically just a color we can’t see, so we can make materials that reflect or absorb it or let it pass through.
By absorbing the UV light before it gets to our skin, it can’t damage our skin. Melanin is a chemical our bodies can produce to do this job, which is why darker skinned people are less prone to sunburn, they have more melanin. That’s also why some people can tan. The UV light triggers the body to produce more melanin to protect the skin from UV.
A sunburn is when your skin cells are damaged from the UV light so your body kills them off so they don’t become cancerous. It’s literally a radiation burn because UV light is radiation.
Latest Answers