Floating Plates

Teacher's Activity Page  [Standards] [Related Hot Links] [Student Page] [PDF File] Background The Aleutian Mountain range contain Mt Katmai and is an excellent example of what happens when different plates (in this case, the Pacific and North American plates) converge. Plate tectonics theory developed from two earlier ideas of seafloor spreading and continental drift. This unifying theory explains the changes of position, shape and size of the continents and oceans. This theory of plate tectonics states that the lithosphere of the Earth is composed of plates that "float" around on the asthenosphere, rather like boats floating on the ocean. As the floating plates move around, the oceans and continents that they carry change position, shape and size. By examining the age of rocks on different continents or on the ocean floor and by comparing similarities and differences in the composition of rocks on the continents, scientists have been able to support the plate tectonic theory.   Resources/Materials/Supplies Video Segment   Per small group: Internet access Supplies for Group 1: 1 large sheet of poster board 250 ml of dried beans 250 ml of paper clips 250 ml of pennies 250 ml of raisins glue scissors   Supplies for Group 2: 1 large sheet of poster board 2 sheets paper 14 x 21 cm scissors tape crayons   Supplies for Group 3: 6 large chocolate bars, 3 each of 2 different densities (For example: Hersheys plain, solid chocolate bar and a 3 Musketeers Bar) paper pencils or markers     Description: In this activity students will: Review the video segment in class. Discussion questions: What tectonic phenomena helped to create the Aleutian Mountain Range? If you could "look back" in time to the Mt. Novarupta eruption, what would you expect to see and hear? How would the atmosphere be affected? What would be happening to the ground on which you would stand? Find and read the information in the Internet Hot Links. Collect the materials needed for their group and read over the instructions for their demonstration carefully. Share presentations based on the group demonstrations with the whole class. Participate in a Q&A session between the class and the presenting group to ensure everyone has understood the pertinent information.   Management Hints Be sure that students have a chance to find and read the information in the hot links given in their assignment. Also, go over the instructions for their demonstration to be sure everyone understands what to do. Prepare the materials and equipment needed beforehand so that moving into small groups will be efficient. Briefly, discuss the directions with each group to be sure they understand what they are doing and what their activity demonstrates. Give groups a limited time to complete their demonstration and class presentations.