Cracking the ice age
Grades: 5 6 7 8 9 10 11 12 Post-Sec.
Edition: Closed captioned.
Publisher: WGBH (Boston, MA)
Climate. Data collection. Earth science. Erosion. Fossils. Geologic time. Geology. Global climate change. Logical reasoning. Plate tectonics. Problem solving. Process skills.
Resource materials for math or science.
This videotape, part of the NOVA television series, presents evidence from investigations that attempt to explain the occurrence of the ice age. The program looks to the Himalayan Mountains and the Tibetan Plateau for answers. It begins by outlining the current scientific understanding about the climate on Earth prior to the ice age. The earth is described as a warm planet whose history has been punctuated by ice ages. The video then shows evidence related to wind patterns and differential warming and cooling of the air. A map is used to show how the island of India has moved due to plate tectonics and crashed into Asia, causing a wrinkling and uplifting of the terrain. The wrinkling is what we call the Himalayan Mountains and the uplifted part is the Tibetan Plateau. A climatologist discusses how this uplifted portion would cause changes in wind patterns and regions of warm and cool air resulting in Asia's monsoonal rains. He uses a computer model to show that as the plateau rose the climate changed to follow the patterns that we see today. Other scientists discuss the changes in the plant communities represented in the fossil record. They indicate that as the plateau rose the temperature dropped.
Viewers see other scientists looking to the greenhouse effect to explain the ice age. Maureen Raymo describes her research that led to the theory that the chemical weathering of the Himalayan Mountains reduced the atmospheric carbon dioxide levels enough to induce a drop in temperatures that began the ice age. The video shows her collecting evidence from the rivers flowing through the mountains and collecting rock samples. She and other scientists looked to the relative concentrations of two strontium isotopes to support their ideas about the decline of carbon dioxide concentrations. The video reports varied responses to Raymo's theory. Viewers learn that scientists disagree about the ways that they interpret their results and continue to look for new pieces that help them explain the ice age puzzle. (Author/JR)
Description: 1 videotape
WGBH (Boston, MA)
|Authors: David Malone; Joseph McMaster; David Paterson; Paula Apsell.|
Corporation for Public Broadcasting (CPB); MERCK and Company, Inc; Prudential.
1 videotape (VHS, 60 min. : sound, color ; 3/4 in.)
Record Created: 07/24/2000 Last Modified: 06/29/2005