Breathing of human being

When you breathe in, oxygen enters the lungs and is released into the blood. The blood distributes oxygen throughout the body and carries carbon dioxide back. Carbon dioxide is a waste product of metabolism. When exhaled, the carbon dioxide is then released from the body. In this experiment, students detect the carbon dioxide content in inhaled and exhaled air. This is achieved with the help of calcium hydroxide by first making lime water. By blowing exhaled air into the lime water, the carbon dioxide is detected.