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Goals and Objectives
Background
TOPEX/Poseidon
There is an explosion of knowledge in the field of space science! With satellites, the Hubble Telescope and the Galileo orbiter, just to name a few of the instruments in space, we have pictures and data at our fingertips, thanks to the Internet.
In 1979, NASA and JPL joined resources to build TOPEX-- a satellite with an altimeter to measure the height of the world's oceans. Simultaneously, the French were planning a similar mission which they had named, Poseidon, after the Greek god of the sea. The French and the Americans agreed to work together and renamed the mission, TOPEX/Poseidon.
TOPEX/Poseidon was launched in August of 1992 and will continue until September of1998. It flies at an altitude of 1336 km (830 miles) above the earth and has exceptional accuracy in measuring the sea surface height. The TOPEX/Poseidon satellite is continually sending data to the earth. Every 10 days it measures more than 90% of the oceans and makes 127 orbits around the earth. It measures the exact shape of the ocean's surface, and the data is used to show changes in the ocean's topography over time. These data are important to scientists for determining ocean currents, climate trends and for improving weather forecasting. The data has also made it possible to develop global maps of tides everywhere in the deep seas. These maps are accurate within 2 cm. This data is helping scientists to understand the role that the oceans play in global climate.
Why are tides important?
The scavenger hunt in the first lesson begins with the topic of tides. Why are tides important? Most of us do not rely upon tidal charts. Since California is a coastal state, tides affect us.Tides are important for marine navigation, for planning the development of coastal communities and highways, for pollution studies, for harbor channel maintenance and, in some instances, for power generation.
In the United States, there are four Physical Oceanographic Real-Time Systems (PORTS) set up: San Francisco, Houston, Tampa and New York City. These real-time systems have shown discrepancies between predicted tidal charts and actual tides. For example, PORTS is needed in Houston/Galveston because the tidal predictions have been inaccurate due to dredging and sedimentation in the bays of Galveston and Houston. These alter circulation patterns. Between 1986 and 1991 there were 1240 groundings many of which involved oil tankers.
The Science Lesson
This lesson is designed to grab kids' interest and imagination! The role of the teacher is essential. Students should be provided with a basic introdution to tides which will help them with the first activity, "The Scavenger Hunt." In this activity, students will search for information which can be found in most textbooks and hot links. They will need help to organize their research and to clarify their understanding of the concepts.
Reading is an essential component of this lesson. To perform the interactive activities, students will need to read and follow directions. For example, the tide predictions programs has to be read to properly input their site of interest. The graphics and the interactive components will help the students to understand what they read.
The menu of activities placed in the "Show Your Stuff" section is intended to develop scientific skills in the student. An atlas is necessary to locate coastal regions and to determine longitude and latitude to reference their sites in the database. Teachers and students will be doing science. They will be using data to investigate the questions they have selected.
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