5th Grade Science — The Human Body — Fearfully and Wonderfully Made
Students will learn how the respiratory system provides oxygen to the body and removes carbon dioxide, and how its design reflects God's creative genius.
Every minute of every day, you breathe in and out about 15 to 20 times — that is over 20,000 breaths each day! Your respiratory system is responsible for bringing fresh oxygen into your body and removing carbon dioxide, a waste gas. This exchange happens automatically, even while you sleep, because God designed your body to keep breathing without you having to think about it.
When you inhale, air enters through your nose or mouth. Your nose is specially designed with tiny hairs and moist mucus membranes that filter dust, germs, and particles from the air before it reaches your lungs. The air then travels down your trachea (windpipe), which is reinforced with C-shaped rings of cartilage to keep it open — like rings holding a vacuum hose in shape. God thought of every detail!
Your trachea branches into two bronchi, one leading to each lung. These bronchi divide into smaller and smaller tubes called bronchioles, like branches on a tree. At the very end of these tiny tubes are clusters of air sacs called alveoli. You have about 600 million alveoli in your lungs! If you spread them all out flat, they would cover an area the size of a tennis court. God designed this enormous surface area to maximize the exchange of oxygen and carbon dioxide.
The actual gas exchange happens in the alveoli. Oxygen passes through the thin walls of the alveoli into tiny capillaries, where it is picked up by red blood cells. At the same time, carbon dioxide moves from the blood into the alveoli to be breathed out. This two-way exchange happens in a fraction of a second, billions of times a day. Such precision and efficiency could only come from an all-knowing Creator.
Your diaphragm, a dome-shaped muscle below your lungs, powers your breathing. When it contracts, it pulls down and creates space for your lungs to expand and fill with air. When it relaxes, it pushes up and forces air out. The Bible tells us that God Himself breathed the breath of life into the first man, Adam (Genesis 2:7). Every breath we take is a reminder of God's gift of life.
Try this breathing experiment: Breathe normally and count your breaths for one minute. Then run in place for one minute and count again. How many more breaths did you take? Why does your body need more oxygen during exercise? Create a model of the lungs using two balloons inside a cut plastic bottle with a rubber glove stretched over the bottom to act as the diaphragm.