K-Bass Sun Podcast

When you add a drop of food coloring to a glass of water, the color gradually spreads throughout the water as dye molecules seep from a zone of high concentration to zones of low concentration. This natural tendency for molecules to spread out of a region where they are concentrated into a region where they are not is called diffusion. Inside your body, carbon dioxide is produced by cells in your tissues, so blood traveling back to your lungs is rich in CO2.