Search NOVA Teachers

Back to Teachers Home

NOVA scienceNOW: Profile: Edith Widder

Viewing Ideas

Before Watching

  1. Create a class poster illustrating ocean zones. Explain to students that ocean zones are layers within the ocean that contain distinctive plant and animal life. Group the class into five teams, and assign each team one of the following zones:

    1. Sunlight Zone
    2. Twilight Zone
    3. Midnight Zone
    4. Abyssal Zone
    5. Hadal Zone

    Tell students they should conduct research using books or the Internet to determine the range of depths where their zone is located in the ocean; any idiosyncratic environmental characteristics of their zone, such as temperature, pressure, amount of light, and plant life; and examples of organisms found in that zone (see table below for sample information). After students have completed their research, attach a large piece of butcher paper to a wall. Divide the paper into five horizontal sections to represent the different zones. Have students summarize the information they found in the appropriate zone on the butcher paper. Ask them to include illustrations and/or photos of the organisms that reside in their zone.

    Zone Depth (in meters) Characteristics Sample Organisms
    Sunlight Zone 0 m - 200 m top layer of the ocean where there is enough sunlight for photosynthesis; hence plants tuna, sharks, dolphin, jellyfish, plankton
    Twilight Zone 200 m - 1000 m a dim zone where some light penetrates, but not enough for photosynthesis; water depleted of oxygen around 500 m. swordfish, squid, wolffish, cuttlefish, shrimp
    Midnight Zone 1000 m - 4000 m the deep ocean layer where no light penetrates, no living plants lanternfish, giant squid, vampire fish, frill shark, sponges, whales, bioluminescent fish
    Abyssal Zone 4000 m - 6000 m bottom layer of the ocean; almost freezing water and immense pressure tripod fish, deep-sea anglerfish, giant squid, rattail
    Hadal Zone 6000 m - 11000 m the waters found in the ocean's deepest trenches; immense pressure (over 16,000 psi); near freezing except for superheated temperatures near thermal vents. oarfish, sea anemones, sponges, mollusks, sea cucumber, echinoderms
  2. Demonstrate the concept of bioluminescence. Ask students if they know what the term bioluminescence means. Allow them to suggest answers. Then, if no one answers correctly, explain that it means "living light" and refers to the ability of living organisms to produce light. Ask if students know of examples of living things that can generate their own light. (Answers might include fireflies, some click beetles, certain sea creatures, algae, and/or bacteria.) Then ask how such organisms might be able to accomplish this. (Answers will vary.)

    Show students a glow stick (available from party stores, hardware stores, or variety stores). Explain that a glow stick generates light through a chemical reaction. The stick contains two solutions (usually hydrogen peroxide and a phenyl oxalate ester) that are kept apart by a glass tube. When the tube is broken, the chemicals combine to form light. Demonstrate this by breaking the stick and shaking it. Explain that bioluminescent light is created in a similar way, when oxygen combines with two other chemicals (luciferin and luciferase).

    Brainstorm with the class the benefits that bioluminescence might have for a creature's survival. Have students record their suggestions. (Suggestions may include: camouflage, attract mates, clouds of bioluminescent chemicals repel predators, communication, etc.)

  3. Consider the challenges of underwater exploration and research. Ask the class to imagine they are conducting research on organisms living in the various ocean zones. Have students brainstorm the kinds of challenges they might face in each zone. (Answers may include challenges such as the need for underwater breathing equipment, managing extreme pressure and temperatures, dealing with lack of light, etc.) Record answers on the board.

After Watching

  1. Investigate how water depth affects color. Remind your class that, according to the segment they watched, most undersea creatures cannot see the color red. Tell students they are going to investigate how water depth affects color. Provide teams of students with four pieces of transparent blue plastic (like the plastic used for book report covers; either 8 ½ x 11 inches or 4 ¼ x 5 ½ inches); one sheet of black construction paper; and several small squares (approximately 1" x 1") cut out of red, orange, yellow, green, blue, black, and white construction paper. Have each team make a chart on a separate piece of paper, similar to the one shown.

      Red Orange Yellow Green Blue Black White
    1 Layer
    2 Layers
    3 Layers
    4 Layers

    Explain that the black paper represents the darkness of the deep ocean, the colored squares represent sea creatures, and the plastic pieces represent ocean depths. Have students scatter the "creatures" on the black background. Then ask them to observe the paper through one layer of the blue plastic. They should describe in their chart anything they notice about changes to the colors, and they should indicate if any of the colors seem to "disappear." Have students repeat the experiment, looking through two layers of plastic, then three layers, and finally through four layers of plastic. When students have finished, have them share their observations with the class. (In general, students should find that the colors "disappear," or become indistinguishable from the black background, in the following order: black, red, orange, yellow, green, blue, white. Depending on the shade of the blue filter, the final colors may still appear through all four filter layers.)

    If you wish, explain to students that the ocean is blue due to the absorption and scattering of light. In water, the blue wavelengths of light are scattered, similar to way blue light scatters in the sky. However, the red, orange, yellow, and green wavelengths of light are absorbed, so that the remaining light we see is composed of blues and violets.

  2. Design a timeline of technology used for ocean exploration and research. Discuss Dr. Widder's camera—the Eye in the Sea. Ask students to name some of the problems Widder faced taking pictures of deep-sea organisms (lack of light, pressure, attracting organisms, submersibles scare creatures) and the ways in which she overcame her problems (silent, lures organisms with bait and electronic light, waterproof.) After the discussion, group students into teams and ask each team to research ocean exploration methods and technology that were developed during one of the following time periods:

    • 5000 B.C.-1 B.C.
    • 1 A.D. -1600
    • 1601-1800
    • 1801-1900
    • 1901-2000
    • 2001-present

    Have teams identify different types of inventions and technologies for their given time period. They should record on a class timeline the name of the invention/technology, along with the date it was developed and the name of the inventor/scientist. You might also ask them to include illustrations and/or photos of the inventions/technologies. [Examples: 5000 B.C. -1 B.C.: first diving bell; 1 A.D.-1600: first true diving bell, plans for first submarine; 1601-1800: first submarine, first waterproof suit, first diving suit; 1801-1900: SCUBA developed, soundings used to investigate ocean, discovery of deep-sea life using dredging; 1901-2000: first deep-ocean dive, bathythermograph invented, Halibut (underwater robot) invented; 2001-present: robot-operated vehicles (ROVs) and autonomous underwater vehicles (AUVs) used for deep-sea exploration and seafloor mapping, Eye-in-the-Sea (Widder's camera) developed.]

  3. Research bioluminescent sea creatures. Remind students that bioluminescence refers to the ability of living organisms to produce light through a chemical reaction. Tell students they will be researching bioluminescent sea creatures. Divide the class into groups and have each group research and create a poster about a bioluminescent organism. (Examples include: copepods, dinoflagellates, sea fireflies, certain anglerfish, certain jellyfish, vampire squid, flashlight fish, cookie-cutter shark, viper fish, and certain octopi.) The poster should include the organism's name, description, location where the organism is found, bioluminescent features, and a description of any role bioluminescence seems to play in the organism's survival (i.e., attracting prey, camouflage, protections, communication, etc.) After groups have completed their posters, have them present them to the class.

  4. Investigate careers in marine science and oceanography. Tell students that there are numerous careers in marine science and oceanography. Have students access the NOAA Ocean Explorer: OceanAGE Careers Web site ( to view video profiles, interviews, and background materials related to the work of people in various ocean-related professions. After students have explored the site, ask them to choose one career that particularly interests them and do additional research on that career. They should discover what the job entails, necessary education and training, the kinds of organizations that employ individuals in the position, the missions of the organizations, the typical salary range, the demand for the job and projections for the future, and where across the globe people are practicing the career.

Links and Books

Web Sites

NOVA scienceNOW
Offers resources related to marine biology, including additional activities, streamed video, and reports by experts.

The Bioluminescence Web Page
This University of California Santa Barbara site contains information about the fundamentals of bioluminescence, descriptions and photos of bioluminescent organisms, current research in the field, and more.

Latz Laboratory: Scripps Institution of Oceanography
Includes articles on bioluminescence, questions and answers about the phenomenon, detailed descriptions of dinoflagellates and bioluminescent plankton, as well as links to Web pages and a bibliography.

NOAA Ocean Explorer
Offers a wealth of information about the ocean realm. Includes detailed information about expeditions, projects, new technologies, and the history of ocean exploration. The gallery contains large collections of still images, audio, and video.

Ocean Research and Conservation Association
Promotes awareness about the value of the ocean for human existence on the planet.

Sea and Sky: Ocean Exploration Timeline
Presents a detailed timeline of ocean exploration from 5000 B.C. to the present day.

University of Wisconsin Sea Grant: Underwater Exploration Timeline
Includes a timeline of ocean exploration that includes glossary links and illustrations.

Woods Hole Oceanographic Institution
Includes a wealth of information on different ocean topics, such a climate, ocean life, technology, and geology. Also include video, photographs, and multimedia interactives.


The Bioluminescence Coloring Book
by Dr. Edith Widder.
Harbor Branch Oceanographic Institution, 1998.
Includes information and line drawings of bioluminescent creatures.

The Deep: The Extraordinary Creatures of the Abyss
by Claire Nouvain.
University of Chicago Press, 2007.
Presents photographs of and essays about creatures living in mid-sea to the abyss levels of the ocean.

Ocean: The World's Last Wilderness Revealed
by Robert Dinwiddle.
Dorling Kindersley, 2006.
Explores the details of ocean environments, from coasts and seashores to shallow seas, the open ocean, and polar waters, as well as the diversity of marine life. Includes photographic essays and illustrations, and satellite-derived maps.

The Winking, Blinking Sea: All about Bioluminescence
by Mary Batten.
Millbrook Press, 2000.
Presents an overview of bioluminescent marine organisms for elementary students. Includes color photographs.

Activity Author

Margy Kuntz has written and edited educational materials for more than 24 years. She has authored numerous educational supplements, basal text materials, and trade books on health, science, math, and computers.

Teacher's Guide
NOVA scienceNOW: Profile: Edith Widder

Support provided by