In the middle of the day, lay the papers, with the white sheet on top, on a table located outdoors and in direct sunlight. Use the transparent tape to tape the papers to the tabletop. After 2 or more hours, remove the papers from the table and separate them. Observe the color of the red paper. Excessive UV can be harmful to other forms of life as well.
Melanin is a dark-colored substance that absorbs UV before it can cause damage to the skin.
Sunblock protects you from sunburn by preventing the UV in sunlight from striking your skin. The red paper is covered with pink polka dots because the red coloring pigment in the paper combined with oxygen in the air and faded. This happens naturally over a period of time, but the process is accelerated in the presence of bright sunlight. Punching holes in the white paper allowed the sunlight to hit the red paper beneath and accelerate the natural process of fading. Amazing Sun Fun Activities .