Water Molds (Oomycetes)

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In this laboratory activity, learners use a simple procedure to bait oomycetes from water and/ or soil and then examine these fungus-like organisms with the microscope to see how they look. They will see large hyphae, sporangia and swimming asexual spores (zoospores), the structures involved in sexual reproduction (oogonia and antheridia), and how the shapes and sizes of these structures may vary among different kinds of oomycetes. Learners may then design their own biodiversity experiments to see if the use of different natural water sources, different kinds of soils, or different baits affect the variety of oomycetes baited. Please scroll down for activity component links.

Quick Guide

Preparation Time:
1 to 2 hours

Learning Time:
1 to 7 days

Estimated Materials Cost:
$1 - $5 per group of students

Age Range:
Ages 11 - 18

Resource Types:
Activity, Demonstration, Experiment/Lab Activity, Lesson/Lesson Plan


Materials List (per group of students)

  • small jars with lids
  • small glass or clear plastic dishes
  • microscope slides, coverslips
  • forceps, probes
  • compound microscope, binocular dissecting microscope
  • whole or cut fruit such as apple or pear
  • popped popcorn kernels (no butter or salt!)
  • sesame seeds
  • dead insects (flies, ants, etc.)
  • spider web (would on a toothpick)
  • insect wings
  • pollen
  • thin pieces of plant tissue like onion skin, grass blades, etc.
  • water from a relatively clean, natural water source
  • boiled and cooled distilled water for baiting from soils
  • Natural soils


  • Life Sciences
    • Cells
      • Cell Structure and Function
      • Cell Division
    • Diversity of Life
      • Protists and Fungi
      • Classification
    • Ecology
  • The Nature of Science
    • The Scientific Process
      • Conducting Investigations

Informal Categories

  • Nature and Environment


To use this activity, learners need to:

  • see
  • see color
  • touch

Learning styles supported:

  • Involves hands-on or lab activities


Components that are part of this resource:

This resource is part of:

Access Rights:

  • Free access


  • Schumann, Gail L. ; Jasalavich, Claudia A.


  • All rights reserved, The American Phytopathological Society, 2011