Skin Lab: The Organ You Wear

Your skin is the heaviest organ you own, and you are wearing it right now. Take it apart, test how it feels touch, see how sweat really cools you, and match its five jobs to real life.

AIR fingertip, from the side the cut stops short of the red vessels sweat turns to vapor and carries heat away water leaves, salt and a little urea stay behind water beads up and stays outside D D UV light + skin cells = vitamin D the tiny muscle pulls the hair upright oil (sebum) coats the hair and skin fat is a poor path for heat, so body heat stays in

Printable student worksheet (PDF) · two pages, goes with this lab
Low-write worksheet (PDF) · same questions with tick boxes, word banks and worked examples
Teacher guide: NYSSLS, SEP and CCC alignment (PDF)

These are models, so every run gives the same answer. The touch gaps are rounded typical values for adults, after Weinstein's 1968 body map; your own will be a little different. The runner model uses real heat numbers (a 70 kg body, 2,430 joules to evaporate each gram of sweat) but is simplified: one runner, 30 minutes, 27 °C (81 °F) air. Anatomy & Physiology, Hole's Essentials 6.1 to 6.4: Parts and Functions of the Integumentary System.