In this activity, you will create a model that demonstrates convection currents in Earth’s asthenosphere.
Estimated time to complete: 1 hour
If you're using an Edmentum lab kit, remove the food coloring from the bag labeled "Common Materials." In addition to the food coloring, gather all the other items appearing in the following list. If you aren’t using an Edmentum lab kit, please check with your teacher for help.
You’ll need these materials:
food coloring
large, transparent glass or plastic container (such as a pitcher)
small, transparent glass beaker or jar (such as a baby food jar)
hot and cold tap water
aluminum foil
rubber band
5 to 10 small pieces of paper, approximately 2 centimeters by 2 centimeters
pencil with a sharp point
Follow these steps to create your model, and then answer the questions:
Fill the large beaker about three-fourths full with cold tap water.
Fill the small beaker about three-fourths full with hot tap water and stir in 5 to 10 drops of food coloring. Then carefully add additional hot water to the small beaker until it is filled to the brim.
Cover the top of the small beaker with aluminum foil and secure the foil with a rubber band.
Carefully lower the small beaker into the large beaker of cold water.
Place the small pieces of paper on the surface of the cold water.
Without disturbing the water, immediately use the tip of the pencil to make two small holes, about 2 millimeters in diameter, in the aluminum foil covering the small jar.
Observe the contents of the beaker and the paper pieces on the surface of the water. Record your observations and analysis by answering the following questions.
Part A
Describe what happened to the colored water and the pieces of paper after the holes were punched in the material covering the beaker.
Part B
Which part of your model represented Earth’s tectonic plates? Which part represented the asthenosphere in the mantle?
Part C
Explain what happened to the model’s tectonic plates. Did they move together or apart? Which type of plate boundary does the model represent? Describe the mechanisms and processes involved in their motion.
Part D
How well do you think this lab modeled the movement of Earth’s tectonic plates and its convection currents? Explain your reasoning. What geologic factors were you not able to model in this lab?
To explain the process and answer the questions, we need to follow the steps provided in the activity.
1. Fill the large beaker about three-fourths full with cold tap water.
- To do this, find a large, transparent glass or plastic container (such as a pitcher) and fill it with cold tap water until it is about three-fourths full.
2. Fill the small beaker about three-fourths full with hot tap water and stir in 5 to 10 drops of food coloring. Then carefully add additional hot water to the small beaker until it is filled to the brim.
- Locate a small, transparent glass beaker or jar (such as a baby food jar) and fill it about three-fourths full with hot tap water. Add 5 to 10 drops of food coloring and stir. Then, slowly add more hot water until the small beaker is completely filled.
3. Cover the top of the small beaker with aluminum foil and secure the foil with a rubber band.
- Take a piece of aluminum foil and cover the top of the small beaker, making sure it is tightly secured with the help of a rubber band.
4. Carefully lower the small beaker into the large beaker of cold water.
- Gently place the small beaker, covered with aluminum foil, into the large beaker filled with cold water, taking care not to spill or disturb the contents.
5. Place the small pieces of paper on the surface of the cold water.
- Take 5 to 10 small pieces of paper, approximately 2 centimeters by 2 centimeters, and place them on the surface of the cold water in the large beaker.
6. Without disturbing the water, immediately use the tip of the pencil to make two small holes, about 2 millimeters in diameter, in the aluminum foil covering the small jar.
- Using the tip of a sharp pencil, carefully poke two small holes, approximately 2 millimeters in diameter, in the aluminum foil covering the small beaker without disturbing the water or the setup.
Now, let's answer the questions:
Part A: Describe what happened to the colored water and the pieces of paper after the holes were punched in the material covering the beaker.
- After the holes are punched in the aluminum foil covering the small beaker, the colored water will start flowing out of the small beaker into the surrounding cold water in the large beaker. This movement is similar to the convection currents in the Earth's asthenosphere. As the colored water flows out, the pieces of paper on the surface of the cold water will start moving and floating along with the current.
Part B: Which part of your model represented Earth’s tectonic plates? Which part represented the asthenosphere in the mantle?
- In this model, the small beaker, covered with aluminum foil and containing the hot water and food coloring, represents Earth's tectonic plates. The large beaker filled with cold water represents the asthenosphere in the mantle.
Part C: Explain what happened to the model’s tectonic plates. Did they move together or apart? Which type of plate boundary does the model represent? Describe the mechanisms and processes involved in their motion.
- In the model, the tectonic plates represented by the small beaker moved apart. The model represents a divergent plate boundary, where two tectonic plates move away from each other. This movement is caused by the density difference between the hot water inside the smaller beaker and the cold water in the larger beaker. The hot water being less dense rises up, creating a convection current, and flows out from the holes punched in the aluminum foil. As a result, the tectonic plates move apart.
Part D: How well do you think this lab modeled the movement of Earth’s tectonic plates and its convection currents? Explain your reasoning. What geologic factors were you not able to model in this lab?
- This lab provides a simple but visual representation of the movement of Earth's tectonic plates and the convection currents in the asthenosphere. It helps to understand the basic concepts and mechanisms involved. However, it is important to note that this lab is a simplified model and does not capture the complexity of the actual Earth system. It does not account for other factors like the lithosphere, subduction zones, crustal deformation, or how different plate boundaries interact. Therefore, while it provides a starting point for understanding, it is not a comprehensive representation of all geologic factors involved in the movement of tectonic plates and convection currents in Earth's asthenosphere.