How Does the Planet Work Together?

Explain how Earth has a hydrosphere, lithosphere and atmosphere and that they all interact with each other. The carbon cycle drives several relationships and is the main factor behind climate change.

Equilibrium of Earth

Gaia, "Mother Earth"

There’s a popular hypothesis that Earth acts as if it were a living thing.  This doesn’t mean that some scientists think that there’s a giant mouth somewhere next to a pair of gigantic eyeballs that are staring at you.  No, that would be weird.  The thinking that Earth is a living thing is called the “Gaia Hypothesis,” and isn’t so strange once you actually get to thinking about it.

Earth is made up of several different big spheres, or units, that work together.  The biosphere contains all living things, the hydrosphere has all of the water, the lithosphere is made up of rock, and atmosphere contains all of the gases.  These aren’t separate things in separate places.  Consider your body: you are made up of living cells (biosphere) that contain water (hydrosphere) and minerals (lithosphere) which are used to convert oxygen to carbon dioxide (atmosphere).  You have a miniature Earth in your body!  Creepy!

Biosphere, Atmosphere, Lithosphere, Hydrosphere

All of these different spheres depend on each other in order to maintain the equilibrium of Earth.  The oceans absorb carbon dioxide and heat from the atmosphere, helping to make sure that the atmosphere has the right balance of gases for living things to survive.  Rocks on Earth break and form things like valleys, which often fill with water to catch rainfall from the atmosphere.  Some organisms help to break larger rocks up to form soil so that plants can grow and convert carbon dioxide to oxygen.  In fact, it took billions of years just for Earth to get to the point where there is a balance, and now due to many destructive activities, we humans are throwing off that equilibrium.

Just like a living thing, Earth transports nutrients, gets rid of wastes, moves energy around and maintains homeostasis.  But it’s this last part that we are in danger of messing up: the homeostasis of Earth.  Do you remember that homeostasis is the balance between the inside and outside of an organism?  Right now, Earth has dangerously high levels of carbon dioxide in its atmosphere, and much of that carbon dioxide is coming from burned fossil fuels that were mined from deep inside the Earth.  This is causing temperatures on the surface of Earth (and the oceans) to rise very quickly.  Guess what?  That’s not homeostasis!

Global Warming changes

Global warming is the name for this increase in carbon dioxide, methane and other gases that cause Earth’s temperature to rise.  97.5% of climate scientists agree that global warming is happening because of what we are doing: driving, flying, raising cattle and pigs for meat, and destroying forests.  Some scientists disagree, stating that Earth always has warmed up and then cooled down in a cycle, and that humans have little to nothing to do with current global warming.  What do you think?

1. What are the four major spheres of the Earth?  Name what each one contains.
2. What is the Gaia Hypothesis?
3. In what ways is Earth like a living thing?
Put it together
4. Consider the fossil fuels that are extracted from Earth:
  • Where did those fossil fuels originally come from?
  • How long did it take for the fossil fuels to get there?

5. What do you think about global warming?  Explain your opinion with at least two reasons.
Think about it
6. Make a diagram or drawing demonstrating how Earth's equilibrium is maintained.  Include at least four different ways that equilibrium is maintained and clearly label each one.

8. What can radiometric dating tell scientists?
9. Name one unsustainable behavior for each of farming, mining and timber.
10. What is a landfill?
Biosphere, Hydrosphere, Lithosphere and Atmosphere
  1. Fill in the chart below by giving an example of how the sphere on the top affects the sphere along the left-hand side.  One of the squares has already been filled in for you:  The hydrosphere affects the lithosphere when it causes erosion to occur.
  2. Once you are finished with twelve of the sixteen squares, put a star in the remaining four.  Figure out examples of the remaining four by asking others or by doing research.
  3. For each of the four starred examples, make a sketch and write a fictional sentence about that interaction.
Top affects left Biosphere Hydrosphere Atmosphere Lithosphere
Lithosphere Erosion
Climate Change Debate

You will be preparing for a debate about the causes of climate change.  For this debate, you will be using the template available here or in the book as “Debate” in the “Projects” section.  You will choose team members to do the following:

  • Write the opening statement
  • Write the 15 questions
  • Write responses to the questions you think will be asked
  • Help other team members with their assigned tasks

The topic for this debate is solution to climate change.  You will need to read several articles in order to form an opinion for or against the following statement: “The best solution to climate change is to change the way that we live; technology can help us limit climate change but technology is not the solution.”

Designing Greenhouse Effect Experiments
  1. Get the following materials per group: 2 water bottles, 1 plastic bag, 1 piece of string, 1 length of masking tape, 2 thermometers, 1 piece of cardboard, 2 rocks, 1 pair of scissors
  2. Cut one bottle half-way from the bottom.  Cut the other where it narrows for the neck.
  3. Using masking tape, attach the thermometers to the inside of the bottles.
  4. Tape small cardboard pieces over the thermometers’ bulbs so that it is not exposed directly to the rays of the sun (or light bulb, if done inside).  The bottom of the thermometer should be 1 inch from the bottom of the bottle.  Remove the label of the bottle so it doesn’t interfere with the incoming energy.
  5. A dry, clean rock should be place in the bottom of each bottle to prevent it from tipping over.
  6. The taller bottle should be covered with clear plastic held in place with a rubber band. This is the “greenhouse.” The short bottle should remain uncovered. This is the control. Since we are testing the effect of both the sides and cover, both need to be absent in the control.
  7. Depending on your group, you will do one of the following: Put about 2” of water in the base of both; Place moist soil in both; Place dry soil in both; Make no changes to both.
  8. Record the starting air temperature in each bottle.
  9. Place your thermometer in open sunlight, with the thermometers facing away from the sun.
  10. Record the temperature inside each bottle every 2 minutes for 20 – 30 minutes.
  11. Graph temperature versus time.
  12. How is this experiment like and unlike the real atmosphere?
  13. How is this experiment like and unlike global warming?
  14. What was the purpose of the short bottle?
  15. From greatest to least effect, list the different substances used in the bottles.
  16. Where do you predict that the biggest effect of global warming will be on Earth?
  17. Where do you predict that the smallest effect of global warming will be on Earth?
    Ethics of Climate Change: Cancun 2010

    The Framework Convention on Climate Change is meeting starting on November 29, 2010 in Cancun, Mexico.  Go to to start this webquest.

    1. Click on “UNFCCC emissions data visualized using Google Maps“.
    2. Select “Transport” from the first drop-down box, carbon dioxide (“CO2″) from the second drop-down box, and then “2008”.  Who is most responsible for carbon dioxide pollution due to transportation in 2008, and how many billion grams (Gg) were polluted?
    3. Use the maps to answer the following questions: Which country had the biggest percentage increase in methane production in agriculture from 1990 to 2008?  Which country had the biggest decrease?
    4. Use the maps to answer the following question: Which country had the biggest percentage increase in total greenhouse gas production (Aggregate GHGs) from waste between 1990 and 2008?  Which country had the biggest decrease?
    5. Click on “Essential Background” and then “Feeling the Heat”.  Use the information in this section to find answers to questions #6 – 10.
    6. What are five major pieces of evidence to support climate change?
    7. What are three future effects of climate change?
    8. In your own view, what is one thing that should be done to reduce greenhouse gas emissions?  Use evidence from the website to support your opinion.
    9. In your own view, what is one thing that should be done to change peoples’ lifestyles?  Use evidence from the website to support your opinion.
    10. In your own view, what is one thing that should be done to cope with the effects of climate change?  Use evidence from the website to support your opinion.
    11. In general, what is ethics?
    12. Is it ethical to continue the way we’re polluting in order to see what will happen on Earth?  Why or why not?
    13. Is it ethical that developed countries (like the U.S.) should expect developing (poor) countries to make as many lifestyle sacrifices?  Why or why not?
    14. Climate change will cause sea levels to rise so much that the 92,500 people of Kiribati (a series of islands in the Pacific Ocean) lose their homes because their islands are flooded.  What would be an ethical decision to make right now?  What would be an ethical decision to make after they lose their homes?
    The Water Cycle: Evapotranspiration

    Evapotranspiration is the sum of evaporation from the land surface plus transpiration from plants.<br>Credit: Salinity Management Guide

    Evapotranspiration is the sum of evaporation from the land surface plus transpiration from plants. Precipitation is the source of all water.

    What is evapotranspiration?

    The transpiration aspect of evapotranspiration is essentially evaporation of water from plant leaves. Studies have revealed that transpiration accounts for about 10 percent of the the moisture in the atmosphere, with oceans, seas, and other bodies of water (lakes, rivers, streams) providing nearly 90 percent, and a tiny amount coming from sublimation (ice changing into water vapor without first becoming liquid).

    Transpiration: The release of water from plant leaves

    A plant with a plastic bag wrapped around some of the leaves, with condensed transpired water on the inside of the plastic bag.After a plastic bag is wrapped around part of a plant, the inside of the bag becomes misty with transpired water vapor.

    Just as you release water vapor when you breathe, plants do, too – although the term “transpire” is more appropriate than “breathe.” This picture shows water vapor transpired from plant leaves after a plastic bag has been tied around the stem for about an hour. If the bag had been wrapped around the soil below it, too, then even more water vapor would have been released, as water also evaporates from the soil.

    Plants put down roots into the soil to draw water and nutrients up into the stems and leaves. Some of this water is returned to the air by transpiration. Transpiration rates vary widely depending on weather conditions, such as temperature, humidity, sunlight availability and intensity, precipitation, soil type and saturation, wind, and land slope.

    How much water do plants transpire?

    Plant transpiration is pretty much an invisible process. Since the water is evaporating from the leaf surfaces, you don’t just go out and see the leaves “breathing”. Just because you can’t see the water doesn’t mean it is not being put into the air, though. One way to visualize transpiration is to put a plastic bag around some plant leaves. As this picture shows, transpired water will condense on the inside of the bag. During a growing season, a leaf will transpire many times more water than its own weight. An acre of corn gives off about 3,000-4,000 gallons (11,400-15,100 liters) of water each day, and a large oak tree can transpire 40,000 gallons (151,000 liters) per year.

    Atmospheric factors affecting transpiration

    The amount of water that plants transpire varies greatly geographically and over time. There are a number of factors that determine transpiration rates:

    • Temperature: Transpiration rates go up as the temperature goes up, especially during the growing season, when the air is warmer due to stronger sunlight and warmer air masses. Higher temperatures cause the plant cells which control the openings (stoma) where water is released to the atmosphere to open, whereas colder temperatures cause the openings to close.
    • Relative humidity: As the relative humidity of the air surrounding the plant rises the transpiration rate falls. It is easier for water to evaporate into dryer air than into more saturated air.
    • Wind and air movement: Increased movement of the air around a plant will result in a higher transpiration rate. This is somewhat related to the relative humidity of the air, in that as water transpires from a leaf, the water saturates the air surrounding the leaf. If there is no wind, the air around the leaf may not move very much, raising the humidity of the air around the leaf. Wind will move the air around, with the result that the more saturated air close to the leaf is replaced by drier air.
    • Soil-moisture availability: When moisture is lacking, plants can begin to senesce (premature ageing, which can result in leaf loss) and transpire less water.
    • Type of plant: Plants transpire water at different rates. Some plants which grow in arid regions, such as cacti and succulents, conserve precious water by transpiring less water than other plants.
    1. Describe evapotranspiration in your own words.
    2. What is a plant doing when it is transpiring?
    3. How do plants get water for transpiration?
    4. Describe three factors affecting transpiration.
    5. Create a diagram of your own showing four aspects of the water cycle: evaporation, transpiration, precipitation and condensation.