Why do sunburns hurt? // Brains On! Science Podcast For Kids

Episode Overview

• This episode explains the science behind sunburns, tans, freckles, and moles.
• It details how different types of sunscreen work to protect the skin from harmful UV rays.
• Listeners learn why sunburns are not caused by the sun's heat or light, but by invisible radiation.
• The episode provides practical tips for sun safety, including how much sunscreen to use and how to gauge the sun's intensity.

Key Concepts

• UV Radiation: Sunburns are an inflammatory response caused by damage to skin cells from the sun's high-energy ultraviolet (UV) radiation, not its visible light or heat.
• Melanin's Role: Melanin is the pigment that gives skin its color. It acts as a natural defense by absorbing UV radiation. A tan is the skin's attempt to protect itself by producing more melanin after being damaged.
• Types of Sunscreen: There are two main types of sunscreen. Physical blockers (like zinc oxide) sit on the skin and reflect UV rays. Chemical sunscreens are absorbed into the skin, where they absorb UV radiation and convert it into a small amount of harmless heat.
• Cellular Damage: UV radiation can damage the DNA inside skin cells. The body sends more blood to the area to repair this damage, causing the redness and inflammation associated with a sunburn.
• Freckles vs. Moles: Freckles are small buildups of pigment (melanin) caused by sun exposure. Moles are clusters of the cells that make the pigment (melanocytes).

Quotes

• At 02:35 - "Believe it or not, sunburns are not due to light or heat. They're due to something we can't see and we can't feel, that's called ultraviolet radiation." - Dermatologist Dr. Shani Francis clarifies the true cause of sunburns.
• At 14:07 - "When our skin gets a sun tan, it's actually a sign that our skin has been damaged." - Pediatric dermatologist Dr. Ingrid Polcari explains that tanning is the skin's response to injury.
• At 16:43 - "If your shadow is very long, that usually means that the sun is either coming up or about to set... and those UV rays are much less strong. So if the shadow is longer than you are, that's usually a signal that it's pretty safe to play outside." - Dr. Ingrid Polcari shares the "shadow rule" for gauging sun intensity.

Takeaways

• A tan is a sign of skin damage. Everyone, regardless of skin tone, needs to protect themselves from the sun.
• Most people do not apply enough sunscreen. The recommended amount for an adult is a full ounce (the size of a shot glass) to cover exposed skin.
• You can still get a sunburn on cloudy or cold days because UV radiation penetrates clouds.
• Use the "shadow rule": if your shadow is shorter than you are tall, the sun's UV rays are at their strongest, and it's crucial to seek shade and use protection.
• In addition to sunscreen, wearing hats, sunglasses, and protective clothing are highly effective ways to shield your skin from the sun.