Teacher's Corner

Background Standards Objectives Students



There is an explosion of knowledge in the field of spacescience! With satellites, the Hubble Telescope and the Galileo orbiter,just to name a few of the instruments in space, we have pictures and dataat 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 hadnamed, Poseidon, after the Greek god of the sea. The French and the Americansagreed to work together and renamed the mission, TOPEX/Poseidon.

TOPEX/Poseidon was launched in August of 1992 and willcontinue until September of1998. It flies at an altitude of 1336 km (830miles) above the earth and has exceptional accuracy in measuring the seasurface height. The TOPEX/Poseidon satellite is continually sending datato the earth. Every 10 days it measures more than 90% of the oceans andmakes 127 orbits around the earth. It measures the exact shape of the ocean'ssurface, and the data is used to show changes in the ocean's topographyover time. These data are important to scientists for determining oceancurrents, climate trends and for improving weather forecasting. The datahas also made it possible to develop global maps of tides everywhere inthe deep seas. These maps are accurate within 2 cm. This data is helpingscientists to understand the role that the oceans play in global climate.

TOPEX/Poseidon Prime Mission Results
On-line Tutorial on Data Images

Why are tides important?

The scavenger hunt in the first lesson begins with thetopic of tides. Why are tides important? Most of us do not rely upon tidalcharts. Since California is a coastal state, tides affect us.Tides are importantfor marine navigation, for planning the development of coastal communitiesand highways, for pollution studies, for harbor channel maintenance and,in some instances, for power generation.

In the United States, there are four Physical OceanographicReal-Time Systems (PORTS) set up: San Francisco, Houston, Tampa and NewYork City. These real-time systems have shown discrepancies between predictedtidal charts and actual tides. For example, PORTS is needed in Houston/Galvestonbecause the tidal predictions have been inaccurate due to dredging and sedimentationin the bays of Galveston and Houston. These alter circulation patterns.Between 1986 and 1991 there were 1240 groundings many of which involvedoil tankers.



This lesson addresses the following California Science Content Standards.

Grades 9-12

Life, Earth, & Physical Sciences

5b: The relationship between the rotation of the Earth and the circular motion of ocean currents and air in pressure centers.

Investigation & Experimentation


1. The students will use their powers of observation and reasoning to verify tidal patterns.

2. The students will be able to use technology to organize their observations and analyze their data.

3. The students will be able to apply math skills to interpret the data collected either through direct observation or through data tables.

4. The students will be able to use the Internet as a resource for gathering data and exchanging data through e-mail.


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 abasic introdution to tides which will help them with the first activity,"The Scavenger Hunt." In this activity, students will search forinformation which can be found in most textbooks and hot links. Theywill need help to organize their research and to clarify their understandingof the concepts.

Reading is an essential component of this lesson. To performthe interactive activities, students will need to read and follow directions.For example, the tide predictions programs has to be read to properly inputtheir site of interest. The graphics and the interactive components willhelp 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 atlasis necessary to locate coastal regions and to determine longitude and latitudeto reference their sites in the database. Teachers and students will bedoing science. They will be using data to investigate the questions theyhave selected.


For additional background and activities about your activity, the following teaching resources are suggested:
Earth Science, Namowitz and Spaulding
Modern Earth Science, Holt, Rinehart and Winston
TOPEX/Poseidon, Perspectives on an Ocean
This is available from JPL free of charge. Once you are on-line, scroll to the bottom to find the on-line order form.
VideoDiscovery, "The Water Planet" laser disk
Tom Snyder's, "The Great Ocean Rescue"


Educational Resources
A listing of resources which help the teacher to teach about oceans, climate and satellite altimetry.


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