Visit Your Local PBS Station PBS Home PBS Home Programs A-Z TV Schedules Watch Video Donate Shop PBS Search PBS
SAF Archives  search ask the scientists in the classroom cool science

Guide Index

Turtle Travels

Paradise Postponed

The Pan Man

Big Dish

Dust Busting

Viewer Challenge
in the classroom
TEACHING GUIDES


Science in Paradise: Dust Busting


Coral reefs are part of marine environments in underwater communities from the Caribbean to Australia, but many reefs around the world are in serious decline. In this story, scientists work together to find out why one kind of soft coral, the sea fan, has become diseased. The problem begins half a world away, with dust blowing across the Atlantic from Africa.

Curriculum Links
National Science Education Standards
Related Frontiers Shows and Activities
Activity: Microbes, Microbes, Everywhere




CURRICULUM LINKS


EARTH SCIENCE

coral reefs, oceans

ENVIRONMENTAL
SCIENCE


 

LIFE SCIENCE

bacteria, fungus




NATIONAL SCIENCE EDUCATION STANDARDS

SCIENCE AS INQUIRY / LIFE SCIENCE
5-8: Populations and Ecosystems, Diversity and Adaptations of Organisms
9-12: Interdependence of Organisms
EARTH AND SPACE SCIENCE
5-8: Structure of the Earth System
9-12: Energy in the Earth System
SCIENCE IN PERSONAL AND SOCIAL PERSPECTIVES
5-8
9-12:
Populations, Resources and Environments, Natural Hazards
9-12: Energy in the Earth System
SCIENCE IN PERSONAL AND SOCIAL PERSPECTIVES
5-8: Populations, Resources and Environments, Natural Hazards
9-12: Natural Resources, Natural and Human-induced Hazards
HISTORY AND NATURE OF SCIENCE
5-8: Science as a Human Endeavor, Nature of Science
9-12: Science as a Human Endeavor, Nature of Scientific Knowledge




RELATED FRONTIERS SHOWS AND ACTIVITIES





ACTIVITY: MICROBES, MICROBES, EVERYWHERE

Aspergillus fungi belong to a group of non-flowering plants known as imperfect fungi. There are several species. Aspergillus niger is the fuzzy black mildew sometimes found on preserved jellies. Aspergillus flavus grows on stored cereal products. Some species are even used to make antibiotics.

picture of coral Follow the investigation on Frontiers to find out how the fungus gets to the bottom of the ocean. Then try this simple investigation to find out more about the microbes surrounding you.

Breathe deeply. Although you can't see it, you've just sucked in a microbe zoo. To a healthy organism, most of these germs are harmless. But as you see on Frontiers, under the right conditions (and exposed to the right host) some common microbes can cause serious harm. In this activity, you'll explore how a surrounding ocean of air harbors a microbe population that may be cultured on a moist, nutrient-rich surface.


MATERIALS
  • bread
  • 3 sterile petri dishes (with covers)
  • colored pencils
  • distilled water
  • clear tape
  • microscope
PROCEDURE

  1. Moisten three pieces of bread with distilled water. Place each piece in the bottom half of a sterile petri dish. Do not cover these dishes.

  2. Place one open dish in a hidden location in the school cafeteria. Make sure that the dish is secure and will not be handled. Keep the dish exposed for a two-hour period (include lunch time).

  3. Place another open dish in a shady spot outside of the building, away from ants. Again, make sure that you select a protected location. Keep the dish exposed for the same two-hour period.

  4. Wet one end of a cotton-tipped applicator with distilled water. Run this moist end along several tabletops. Then, run the tip in a zigzag pattern over the last piece of moistened bread. Cover this dish and seal it closed with clear tape.

  5. After two hours, cover and seal the two exposed dishes with tape. Set all three covered dishes in a dark closet or drawer.

  6. Each day for one week, examine the appearance of the bread. Do not open the dishes. Record any changes in the bread's appearance. Note the numbers, colors and characteristics of any 'splotches' or 'fuzz' patches that appear within the dish. Use your microscope to examine these microbe colonies. Draw what you see.

  7. At the week's end, your instructor will collect the dishes and dispose of them.
QUESTIONS

  1. In which dish did you expect to see the most microbe growth? Were you correct?

  2. Why were the dishes sealed shut?

  3. Where did the microbe colonies come from?

  4. Why did you use distilled water instead of tap water?

  5. What did this experiment tell you about microbes in the air?
EXTENSIONS

  1. Is water critical to microbe growth? You be the judge. Design an experiment using raw oatmeal flakes, bread mold (handled by your instructor) and distilled water. You'll also need two petri dishes: one will contain moistened oatmeal flakes; the other will be dry. Inoculate both with bread mold. What happens?

  2. Research the story of Sir Alexander Fleming's discovery of penicillin in 1928.

  3. Why are coral reefs called the "rain forests of the ocean"? For more about threats to coral reefs, visit: www.coral.org/Threats.html.
ANSWERS

  1. To restrict any potentially dangerous microbes to this isolated environment.

  2. Spores that dispersed in air.

  3. Tap water may be contaminated with microbes or spores.






 

Scientific American Frontiers
Fall 1990 to Spring 2000
Sponsored by GTE Corporation,
now a part of Verizon Communications Inc.