All life on Earth has evolved to depend on the atmosphere for protection from the sun’s harmful rays or meteorites. It contains the air that we breathe, provides us with warmth and distributes water across the globe. The Earth simply would not harbor life if it weren’t for the perfect recipe of gases that surround it.
The atmosphere surrounding planet Earth is composed of a soup of gases that are held to Earth’s surface by the force of gravity. It is primarily made up of nitrogen, oxygen, and argon. Other gases, called trace gases, are also present. These include water vapor, carbon dioxide, methane, nitrous oxide, and ozone. Additional particles from industrial pollutants, such as elemental mercury, chlorine, or sulfur can be found in the atmosphere. As well as particles from more natural substances, such as pollen, volcanic ash, spores, or even meteoroids.
The atmosphere is made of five main layers. From top to bottom these include: the exosphere, thermosphere, mesosphere, stratosphere, and troposphere. The layers mainly differ in density, pressure and whether the temperature increases or decreases with altitude. The properties of these layers, and their interactions with the sun, ocean, and the surface of the Earth are what create the weather systems that affect our daily lives.
Cultures around the world have been aware of the impacts of weather systems created in our atmosphere. Cultures that are dependent on the rain and sun for agriculture, safe travel, or recreation have learned through observation that weather systems can be predicted prior to their actual arrival.
An example of this is in Kenya with the Abasuba people that live on the islands of Lake Victoria. They know rains are on their way and it is time to plant their crops when they see the Magungu bird fly higher than normal in its route from South to North. The Abasuba say that the bird will look like it is floating in the air. Scientists say that the flight pattern of the bird could be because of the inter-tropical convergence zone, a region near the equator where winds from the northern and southern hemisphere collide. The Lake is located in an area of extreme convection, and could cause the high flight pattern of the bird.
The inter-tropical convergence zone often forms a band of weather systems near the equator.
The atmosphere also shapes people in regions of high altitude. The atmosphere is less dense as altitude increases, meaning less air for people and other organisms to breathe. There have been some interesting adaptations in cultures living in our highest mountains ranges. The Andean people for example have adapted to less oxygen in the air by developing higher hemoglobin concentrations in their blood. Hemoglobin is the oxygen carrying molecule in our blood, and having more of it prevents hypoxia, a severe condition due to an insufficient amount of oxygen. Just as there are physiological adaptations, there are cultural adaptations, such as chewing coca leaves or drinking coca tea like most Americans drink coffee, which increases the oxygen absorption in the blood.
Google Earth and NASA are great resources to allow students to visualize global weather systems. While researching the Kenya example above, I turned to Google Earth to see if I could find the inter-tropical convergence zone and what do you know, I saw the characteristic band of clouds created by the northern and southern hemisphere winds colliding and creating weather systems. In addition, the YouTube resources we have been exposed in this class are evidence that it is a valid means of illustrating science concepts to students of all ages. In particular, the video showing a year’s worth of water vapor motion across the planet and the video of water freezing by boiling was so engaging that it was the source of my whole family’s entertainment this Friday evening. Incorporating Google Earth, NASA, YouTube, and Teachers’ Domain into units of study can only deepen understanding and encourage additional exploration from students.
