A tattoo machine causes a wound that alerts the body to begin the inflammatory process, calling immune system cells to the wound site to begin repairing the skin. It is this very process that makes tattoos permanent.
From the TED-Ed Lesson What makes tattoos permanent? - Claudia Aguirre
Animation by TOGETHER
Umm… what? I’m stumped on this one, guys, any help?
The spheres are superabsorbent polymer filled with water. They are transparent because the water inside the spheres, and the water outside has the same refractive index. When you remove the balls from the water light refracts against them, making them visible.
My mind was blown.