In this section, you will learn about two body systems.  The excretory system removes waste from the body.  The respiratory system removes carbon dioxide, which is one form of waste, from the body.

Along with carbon dioxide, a major form of waste is urine, which is removed by the urinary system.  This is important because removing waste is a crucial function of the body.  Diseases to any of these systems can cause major problems for individuals.

Scientific Concepts:

  • The parts of the respiratory system and what they do
  • The path air takes as it goes into and out of the body
  • The way pressure affects breathing
  • The major parts of the excretory system and the other systems the organs of the excretory system belong to
  • Common diseases of the respiratory and excretory systems


Select a Lesson

How Lungs Work
Take a deep breath in, and slowly let it out. As you do, think about the breaths you take without thinking about it. The truth is, you probably only think about breathing when you are coughing and having a hard time breathing. Even though breathing is not something we think about regularly, it is absolutely …
What’s Your Lung Capacity?
Today you will make a calibrated, or marked, container that you will use to measure your lung capacity. You will fill the calibrated container with water, slide a hose into it, take a really deep breath, and blow in the hose. As the air in your lungs enters the container, it will push out the …
Working Lung Model
Food and air both enter your body through your mouth, diverging when they reach the esophagus and trachea. Food goes to the gastrointestinal tract through your esophagus and air travels to your lungs via the trachea, or windpipe. You will be making a model of how your lungs work in this lab. It will include …
Detecting Carbon Dioxide
An oxygen and carbon dioxide exchange takes place in your bloodstream. When you breathe air into your lungs it brings in oxygen, which is carried from your lungs by red blood cells in your bloodstream. Cells of your body use the oxygen and carbon dioxide is produced as waste, which is carried by your blood …
Scent Matching
We now know that odor molecules are diffused throughout a room by the motion of air molecules, which are constantly moving and bumping into them.  We also know that warm air moves faster than cold air, and that increasing the movement of the air (like with a fan) will increase the diffusion process. In this …
Swallowing
Peristalsis is the wavelike movement of muscles that move food through your gastrointestinal tract. The process of digestion begins with chewing and mixing the food with saliva. From there, the epiglottis opens up to deposit a hunk of chewed food (called bolus) into your esophagus – this is the tube that runs from your mouth …
Diffusion
Everything living produces some sort of odor. Flowers use them to entice bees to pollinate them. We know that the tastes of foods are enhanced by the way that they smell. As humans, each of us even has own unique odor. In this lab, we look at the diffusion of scents. They start in one …
Consuming Oxygen
This experiment not only explains how your body uses oxygen, but it is also an experiment in air pressure circles – bonus!  You will be putting a dime in a tart pan that has a bit of water in it. Then you will put a lit candle next to the dime and put a glass …
All About Kidneys
Although urine is sterile, it has hundreds of different kinds of wastes from the body. All sorts of things affect what is in your urine, including last night’s dinner, how much water you drink, what you do for exercise, and how well your kidneys work in the first place. This experiment will show you how …