The Oxygen Machine Teacher Sheet

The Oxygen Machine Teacher Sheet Photo Credit: Clipart.com


Respiration (breathing) is so automatic that we rarely think about it, unless we feel that enough air is not getting into our bodies. Respiration is the process that allows us to breathe in oxygen and exhale carbon dioxide. Oxygen is then used in our cells as the fuel that transforms the food we eat into energy. Use the information on this sheet to help you discuss with your students the combustion process in terms of producing energy via respiration.

Producing Energy via Respiration
These points should be emphasized:

  1. The body can be described as a combustion engine. The fuel needed for this process comprises sugars and fatty acids (fat deposits in our cells), which we gain by eating food. In order to burn this fuel, oxygen is needed, as it is with any fire. The waste products from the combustion process are water and carbon dioxide. Thus, we breathe because oxygen is needed to burn the fuel (sugars and fatty acids) in our cells to produce energy The air we breathe contains about 21% oxygen. This oxygen is brought into the lungs, where it is transported by the red blood cells to the entire body. Once the red blood cells return to the lungs, the "burnt" carbon dioxide is exhaled.
  2. To help students understand this process, correlate the combustion process to fire. You can begin by discussing how fires begin. In the Santa Monica Mountains, human actions have often been the main cause of fires. In the past, lightning from thunderstorms contributed to fires. Whatever the cause, there are three ingredients that combine to start a fire:
    • Fuel: “Fuel” is any combustible material. During long summer months in the Santa Monica Mountains, shrubs that become dehydrated and dead grasses provide “dry fuel” and burn more easily. When years go by without fire, dead plant material builds up, so when a fire occurs, there is ample fuel to burn.
    • Heat: The typical climate of an area that is susceptible to fires includes long, dry summers with little rain. These conditions increase the temperatures of the ground and “fuel,” making it easier for the “fuel” to ignite and burn. “Dry fuel” ignites easily from sources such as lightning, a burning cigarette butt, broken glass focusing sunlight by reflection or refraction, or a match.
    • Oxygen: Wildfires in the Santa Monica Mountains are triggered by strong winds that blow hot and dry air. This not only increases the oxygen supply and dries out the “fuel,” but also influences the spread of fire. Shrubs are more quickly ignited, as their small-sized leaves are surrounded by plenty of oxygen.

Oxygen Consumption
As is the case with any engine, the "power" of the body depends on how efficiently it can burn fuel. The higher the oxygen intake, the better the cells work, and the lower the burden on our heart and blood circulatory system.

Everywhere on earth, oxygen makes up 20.96% of the gas in air—almost all the rest is nitrogen. The atmospheric pressure helps determine how dense this air is, and therefore what concentration of oxygen the air contains. At 18,000 feet, atmospheric pressure is half what it is at sea level. The pressure of oxygen is therefore also half. As people climb from sea level to these heights, their bodies—and breathing—must adapt to the changing concentrations of oxygen in the air.

Regardless of how fit a person is, the body requires a certain amount of oxygen per kilogram (kg) body weight in order to perform a certain workload. This means that the heavier you are, the more oxygen you need. Let us say that you’re walking at a leisurely speed of 5 km/hr (about 3 miles per hour). If your body weight is 70 kg, you will need about 1 liter of oxygen per minute. If your body weight is 100 kg, you’ll need half as much again, or 1.5 liters/minute!

Age is another significant factor. The oxygen consumption capacity is at its peak when you are about 15-20 years old. (Ever wondered why Olympic champions are so young?!!). After that, it starts to decline slowly but surely.

Gender also plays a role; women have around 30% less oxygen consumption than men. This is one of the main reasons that in general, it is a bit easier for males to lose weight or stay fit.

With a bit of fitness training and physical exercise, the oxygen intake—and therefore the efficiency of the body—can be increased by 20% or more. This means that all body functions will work better and easier.

This increase has dramatic consequences: through moderate exercise, you can achieve a substantial rejuvenation, cutting years off your body’s biological age. In other words, a 50-year old can reach the physical capacity of a 30-year old. This may not seem very important if you are only 10-12 years old now, but the earlier someone starts into the fitness world the healthier that person will be.

This teacher sheet is a part of the The Oxygen Machine lesson.

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