Make a Model Lung
What's something you do all the time, all day and all night, without even thinking about it? Breathing! In fact, you breathe more than 23,000 times in just one day. When you breathe in air, it travels to your lungs which separate out the oxygen your body needs. Your lungs then send back everything you don't need by breathing out. The oxygen is sent to your blood, where it's used to make the energy you need to do everything, like running, eating, and talking.