5.6 Learning about the earth through remote sensing
Essential question: How can satellite images be used to monitor the earth from space?
Students will gain an understanding of how remote sensing — using aircraft, satellites, ocean buoys, etc — can help provide information about the earth and its oceans.
- A variety of maps of different types — road, satellite, topographic, aerial, boating, etc.
- “Monitoring the Earth” handout
- Optional: Student computers with internet access (Necessary for extension activity)
Time required for lesson
Approximately one class period (45-50 minutes)
The USGS (United States Geologic Survey) maintains a data center known as EROS — Earth Resources Observation and Science — which houses archives of satellite images of the earth. The images provide scientists with a record of global environmental and municipal change. The primary satellite used to create these images is the Landsat 7.
Landsat 7 images the earth from 705 km above the earth’s surface. It makes a complete trip around the planet every 99 minutes and takes a complete set of images of the land surfaces every 16 days. A single image covers 183 km X 170 km. (One pixel represents 30 meters on Earth.)
Some of the images taken by the Landsat 7 satellite make use of multispectral imaging technology to convey information about things like vegetation, soils, and bodies of water. All objects reflect solar radiation, and things like plants reflect solar radiation at different angles than things like buildings. Another way to say this is that each object has its own electromagnetic spectrum — the range of possible frequencies of electromagnetic radiation.
Landsat 7 assigns colors to various bands in the electromagnetic spectrum to create color composite images. These images can help us understand what’s on the ground — even from outer space. Using multiple spectral bands, images are created in which vegetation appears in shades of red, with brighter reds indicating more intense vegetation. Areas covered by soil with little or no vegetation appear white or may be shades of green or brown. Bodies of water appear in shades of blue or black, with deep clear water appearing darker than shallow water or water that contains a lot of sediment. The coloration of these images help scientists monitor things like rainforest deforestation, droughts, coastline change, floods, the impact of wars and earthquakes, and many other changes in the earth’s surface.
(Sources: United States Geological Survey’s Landsat Missions website, the USGS “Tracking Change Over Time Classroom Activity,” and the USGS Educational Resource activity Exploring the Earth With Remote Sensing.”)
- Spread the various maps out in stations around the classroom. (Each station should have a different type of map.)
- Have each student visit two of the map stations and make a Venn diagram showing how the two maps are similar and how they differ.
- Have students share their diagrams with others in class.
- Lead a class discussion about how the maps are similar and different. Discussion questions may include:
- Who would use these maps?
- Which careers make use of maps?
- How were these maps made?
- What is the name for a person who makes maps?
- Ask students to name factors resulting in changes to the earth’s surface. Answers will vary, but be sure to discuss global climate change, natural geological processes, human development, etc. Discuss the various methods of monitoring the earth’s surface. Methods include:
- Satellite imagery — Taking photographs of the earth from satellites in space
- Aircraft monitoring — Taking photographs of the earth from airplanes and/or helicopters
- Buoys — Gathering data about the ocean using floating buoys
- Ground truthing — Making direct observations “on the ground” to verify and validate information gathered remotely, e.g. from satellite images, aircraft, and buoys
- Optional: You may want to share with students the background information about how the Landsat 7 satellite uses spectral bands to create images with information about vegetation, soils, etc. (See teacher background above.) Show students examples of images that use this technology from the NASA archive of satellite images. Suggestions include:
- Through class discussion, ensure that students understand the relationship between remote sensing and ground truthing in gathering accurate data about the earth: Remote sensing involves gathering data remotely, from satellites, probes, buoys, aircraft, ships, etc. Ground truthing involves gathering information directly — on the ground (or in the water).
- Guided practice: Have students complete the “Monitoring the Earth” handout.
- Conclude with a discussion about the various professions that gather data about the earth (both through remote sensing and ground truthing), professions that create maps using this data, and professions that rely on the availability of accurate maps. See career information below.
- Individually or in groups, have students use the National Oceanic and Atmospheric Administration’s National Data Buoy Center website to monitor buoys moored in different oceans around the globe. Have students compare and contrast sea surface temperature, wave height, and wind speed.
- Visit the USGS archive of satellite images or the NASA archive of satellite images for further in-class discussion about human-induced and natural changes on the earth’s surface. Some interesting images to examine include:
A list of careers involved in making and using maps via remote sensing, with links to information from the Bureau of Labor Statistics’ Occupational Outlook Handbook.
- Atmospheric scientists (meteorologists)
- Analyze satellite information provided by NASA and the National Data Buoy Center to monitor hurricane and atmospheric data.
- Civil engineers
- Use maps when designing the construction of roads, buildings, airports, tunnels, dams, bridges, and water supply and sewage systems
- Farmers, ranchers, and agricultural managers
- Can use maps and satellite technology that reveals drought areas of farmland for irrigation purposes.
- Fishers and fishing vessel operators
- Monitor sea surface conditions using the global spectral radiometer system provided by NOAA (National Oceanic and Atmospheric Administration). They also utilize maps and GPS (Global Positioning System) for navigation.
- Forest firefighters
- Can track the extent of fire damage and hot-spots using the infrared bands read from satellite images.
- Geoscientists and oceanographers
- Can use maps and satellite information to locate rock formations and outcroppings on land; scan satellite images of the ocean to locate algae blooms, polar activity, and ocean hot-spots and computerized buoys for sea surface temperature.
- Military personnel
- Use maps and satellite imagery to map terrain, water resources, and topographical challenges like mountains, heavy foliage, and the movement of armaments, troops, and supply materials.
- Police officers
- Can use spectral readings of vegetation over land to detect illegal growth of plants.
- Surveyors, cartographers, photogrammetrists, and surveying and mapping technicians
- Responsible for measuring and mapping the Earth’s surface.
Optional resources for more information on the topics covered in this lesson
- Remote Sensing: Geography for Kids
- KidsGeo.com explains how remote sensing technology has changed map-making.
- The Landsat Program
- Landsat, NASA’s remote sensing program, has observed the Earth through satellites for over three decades. On the Landsat website, students can learn how Landsat helps, view the image archive, and benefit from other educational resources, including a landforms quiz.
- Interpreting a Satellite Image
- The Smithsonian National Air and Space Museum Center for Earth and Planetary Studies explains what you can see in a satellite image and then allows you to test your skills.
- Event-Based Science: Remote Sensing Activities
- The Event-Based Science Project offers remote sensing activities based around earthquakes, fires, floods, hurricanes, oil spills, and volcanoes.
- USDA Living Science: Remote Sensing Specialist
- The USDA gives a job description for remote sensing specialists, including information on typical interests, hiring agencies, degree and practical experiences required, and classes to take in high school.
North Carolina curriculum alignment
- Goal 5: The learner will conduct investigations and utilize appropriate technologies and information systems to build an understanding of evidence of evolution in organisms and landforms.