Students should understand the actions of fluids and gases with varying densities, which create convection currents. This demonstration will broaden their understanding of how such currents shape the face of the Earth.
Why does warm air rise? Does the same thing happen with water?
In what other systems does convection current take place? (It occurs in fluids, and air is a fluid too!)
K-12 Earthquake Activity Teaching Modules
A Joint Project of the Network for Earthquake Engineering Simulation (NEES) and the Southern California Earthquake Center (SCEC)
In the spring of 2011, NEES at the University of California Santa Barbara (NEES@UCSB) embarked on a project to develop a comprehensive set of teaching modules for K-12 students that would cover the basics of plate tectonics and earthquake dynamics. The idea for the project grew from the success of the “Make Your Own Earthquake” outreach activity developed by NEES@UCSB, which recently has included the use of the Quake Catcher Network MEMS accelerometer.
The UCSB site received a supplemental grant for Education, Outreach, and Training from NEES that provided funds for an undergraduate student to work on this project. Two NEES REU interns and a SCEC intern were also recruited, for a total of four students working cooperatively on the project over the summer of 2011. NEES@UCSB personnel served as mentors to the students and a Santa Barbara GATE science teacher was hired, through the NEES EOT grant, as a consultant to review the work. The students were asked to incorporate, as appropriate, the use of the QCN accelerometer and real earthquake data in the teaching modules. They were also asked to do a comprehensive survey of earthquake-related teaching materials currently available and to incorporate, with proper references, any of these materials into the new modules.
Over the course of the summer of 2011, the students met weekly with their mentor and the science teacher. In August, a group of local 4th – 6th grade students came to the UCSB campus and tested several of the earthquake activities. The summer interns presented their work at the NEES REU Young Researchers Symposium at UCSB in August and at the annual SCEC meeting in Palm Springs in September.
The 12 earthquake activity modules are summarized below:
Jamison Steidl, Ph.D., Principal Investigator, NEES@UCSB
Sandra Seale, Ph.D., Project Scientist and Outreach Coordinator, NEES@UCSB
Carrie Garner, M.A., Gifted and Talented Education Teacher and Coordinator, Hope School District
Summer Undergraduate Interns:
Sean Allen, Civil Engineering, University of Nevada, Reno
Heidi Pence, Civil Engineering, University of Michigan
Joseph Trudeau, Geology, University of Wisconsin
Hanna Vincent, Mechanical Engineering and Materials, MIT
Earthquake Activity Modules:
9th – 12th Grade: Convection Currents, Hanna Vincent
[Be sure to click the "Docs and Attachments" tab to view and download attachments for this lesson such as handouts and worksheets.]
Earthquake Engineering Component
Learning Objectives and Standards
Links to the National Science Standards and to individual State Science Standards are available by using this link:
California Science Framework, Physics
Standard Set 1: Motion and Forces
When forces are balanced, no acceleration occurs.
Standard Set 3: Heat and Thermodynamics
- Energy cannot be created or destroyed. Heat flow and work are two forms of energy transfer between systems.
- The internal energy of an object includes the energy of random motion of the object's atoms and molecules, often referred to as thermal energy. The greater the temperature of the object, the greater the energy of motion of the atoms and molecules that make up the object.
- Most processes tend to decrease the order of a system over time and that energy levels are eventually distributed uniformly.
- Large clear rectangular tub.
- Five (5) Styrofoam cups.
- Cardboard. Four 4"x4" squares.
- Hot water. (Near boiling).
- Several ice cubes
- Food coloring. One or more colors.
- Dropper or pipet with long neck.
1. Place four of the Styrofoam cups on a table in a rectangle slightly smaller than the dimensions of the tub.
2. Place one of the 4x4 cardboard pieces under each cup.
3. Place tub on the four elevated cups, ensuring that the tub is evenly balanced.
4. Fill tub 3/4 of the way with cold tap water.
5. Using a pipet or dropper, gently deposit a 1"-2" blob of food coloring at the bottom of one edge of the tub.
6. Fill the fifth cup with hot water and place it directly under the blob of food coloring.
7. Watch and wait for the food coloring to start rising.As the food coloring reaches the surface, gently float an ice cube in the opposite side of the tub.
The food coloring makes it possible to visualize the convection current moving in the water. The heat transfers from the cup to the plastic to the water and rises to the surface. The ice cube helps the process along by increasing the temperature gradient between the top and bottom of the tub. Anything floating on the surface of the water will also move with the current. Try setting a leaf or a piece of paper on the surface to see this in action. Now imagine huge tectonic plates being pushed along by similar forces within the mantle of the Earth!
Links and Resources
- Density: Mass per volume.
- Convection current: Current induced by a difference in the temperature (temperature gradient) of liquids and gasses.
- Convection: movement of molecules within fluids (liquids and gasses).
- Tectonic plate: A landmass that composes part of the crust of the Earth and is always in motion, driven by convection current of the mantle of the earth.
- Use the longest-necked pipette or dropper you can find. It will minimize disturbing the water.
- Pick a darker food coloring and remember that yellow looks awkward.
- Styrofoam cups work best, because they are designed to handle hot liquids. Paper coffee cups would also work, although some may not be strong enough to support the tub of water.
- The key is to be as gentle as possible when dealing with the water in the tub. Try not to disturb the water when placing the food coloring or ice cube, because outside influences make it hard to see what is happening in the water
As materials warm, their density (mass per volume) decreases. Conversely, as materials cool, their density increases. Low-density material rises and high-density material sinks. By increasing the temperature at the bottom of the tub, the material cycles up and down as it warms and cools at the bottom and top of the tub. This cycle is called convection current. Tectonic plates that sit on the mantle move slowly (millimeters to centimeters a year), pushed by the convection currents in the mantle.
Community Science Action Guides. (2011). "The Secret Live of Energy, The Energy Solution." Convection, <http://fi.edu/guide/hughes/heattransfer.html> (Aug 2011)
Kobes and Kunstatte. (1999). "Convection." Convection currents, <http://theory.uwinnipeg.ca/mod_tech/node76.html> (Aug. 2011)
Learning modules in this series:
- Everything Important About Earthquakes (And Other Important Information)
- Shake Things Up!
- Fault Slip - Grades 4-5
- Fault Slip - Grades 6-8
- Fault Slip - Grades 9-12
- Mountains and Sedimentary Rock
- Food Fault Lines
- South America and Africa Puzzle
- Convection Current and Tectonic Plates
- Earthquake Waves and Propagation Through a Surface
- Earthquake Waves
- Earthquake Epicenter
What does convection current mean for the geography of our planet? The commonly accepted theory is that convection current in the mantle of Earth is the driving force of tectonic activity.
Researchers should cite this work as follows:
Sandra Seale; Hanna Vincent; NEES EOT (2011), "Convection Current and Tetonic Plates," http://nees.org/resources/3915.