Free Microorganisms Basic Skills Worksheets for grades 3–5. Microorganisms are often introduced only as germs, which misses much of their importance. Wriggling compares helpful food-making microbes, decomposers, varied habitats, and evidence-based decisions about possible harm.
Download the free Microorganisms worksheets
This six-page packet includes two teacher-guide pages, three student worksheets and an 18-point answer key. Students practice 16 tasks: matching, fill-in, classifying cases, multiple choice and explaining evidence. Print the three student pages; keep the guide and key for instruction. No kit or purchase is required.
Meet Wriggling
Gemlings teach science through their personalities and home realms. Wriggling guides learners in Glowspore Grotto. The character’s teaching note introduces the science mission, and the final encouragement recognizes the student’s learning.
Science topics
- Meet Microorganisms
- Helpful Microbes & Food
- Fungi, Mold & Growth Conditions
- Microbes as Decomposers
- Microbes in Many Habitats
- Helpful, Harmful & Evidence-Based Choices
Simple classroom use
Allow about 20–30 minutes or split the work across lessons. Model the toolbox words and read the case cards aloud when helpful. Students match clues, complete ideas, classify cases and explain evidence. Use the answer key to discuss corrections; accept accurate explanations in a child’s own words. Tasks 1–14 earn one point each and tasks 15–16 earn up to two each.
Use prepared photos and teacher-selected data instead of culturing unknown organisms. Compare a bread-making example with decomposition of leaves, asking students to explain what the microbes change and how those changes affect the larger system.
A science teaching tip
Not all microbes are harmful, and not all microscopic organisms are bacteria. Appearance or smell cannot establish whether an unknown sample is safe. The activities use written scenarios rather than handling or growing unknown microbes.
Train, refresh, then assess
Start with free subject vocabulary training or the free subject reading resource. After worksheet practice, open the subject Adventure page to watch the Gemling video for learning or a refresh, then take the free Online Adventure assessment. The worksheet score is classroom practice, separate from that assessment.
Optional hands-on discovery
Dig Kits can extend Discover–Identify–Collect: uncover specimens, identify them using observations and available specimen/trading cards, and organize a collection. Free worksheets and Online Adventures stand on their own. Teachers may purchase available kits, explore the Free Dig Kits campaign, or ask about possible PTA/PTO funding. Signup does not automatically guarantee free kits; current funding and fulfillment conditions apply. PTA/PTO funding is not guaranteed.
Explore Free Dig Kits for your classroom
More free science resources
Life Science Basic Skills collection: 12 subjects, 72 printable pages · Browse the free resource library