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Pre-K through Grade 2
Grade 3 through Grade 6
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Grade Levels Grades 3 through
6
Estimated Teaching Time
30 minutes
Interdisciplinary Connections
- Building technical concepts (Science)
Objectives
Students will learn about germs and become familiar with the shapes
of these illness-causing microbes.
What Students Do
In this activity students will discuss their experiences with
germ-caused illnesses and observe illustrations of germs.
Materials Required
- Magnified images of common germs (blackline
master 1.1, PDF)
- Microscope or photographs of various types of microscopes
- Optional
Overhead projector and transparency film
Advanced Preparation
Duplicate the blackline master
1.1 (PDF) for each student or copy it onto an overhead transparency.
Suggested Sequence
- Ask students to share an experience about being sick. What
was the disease called? What caused it?
- Advise class that germs are tiny living organisms, also called
“microbes,” that cannot be seen without a microscope
and that cause disease. Most germs are either bacteria, viruses
or fungi:
- Bacteria are simple one-celled microorganisms that reproduce
rapidly. Some produce poisonous waste products that cause
disease; some are harmless; and others are beneficial and
even necessary for human life.
- Viruses are primitive protein structures that also cause
disease. Many scientists do not believe they should be classified
as living because they can’t reproduce until they are
inside a host organism’s cell. Once inside, however,
they reproduce by the millions, destroying cells in the process.
- Fungi are plant-like organisms that obtain food by decomposing
dead organic matter or as parasites on living organisms. Like
bacteria, some fungi are poisonous; some cause infection;
and others are not harmful at all, such as garden mushrooms.
- Explain to students that although our discussion will be focused
on germs — those types of bacteria and viruses that cause
most communicable diseases — some bacteria and fungi are
beneficial and, in some cases, even necessary to human life. Ask
whether any knows of a good bacterium or fungus. Provide some
examples. [Acidophilus in yogurt, antibiotic medicines like penicillin.]
- Explain to students that most bacteria can only be seen at 1000x
magnification, while most viruses require electron microscopy
at 100,000x or higher. Show them the microscope or photographs
of various types of microscopes and talk about how they work.
- Ask students where they think bacteria and viruses are most
likely to be found.
- Distribute copies of blackline
master 1.1 PDF (or show transparency) and review the magnified
images of germs with students. Have them describe what each germ
resembles.(NOTE: These images have been taken from a variety of
sources and do not necessarily reflect what a student would see
looking through an optical microscope.)
- Discuss with students some of the common germs, the illnesses
they cause and how they are transmitted.
- Ask students to match these germs to the pictures on blackline
master 1.1 (PDF).
Check for Understanding
Ask the following questions:
- What are the three most common types of microorganisms?
- What are germs?
- Where can microorganisms, such as germs, be found?
- Are all microorganisms harmful to us?
- What kinds of shapes do bacteria have? [Little round balls,
straight rods, twisted spiral shapes.]
- What kinds of shapes do viruses have? [Balls with spikes
sticking out on all sides, loaves of bread, tadpoles, metal screws
with spider legs.]
Extensions
- Design a bacterium or virus of your own and give it a name.
- Build a model bacterium or virus with classroom materials or
recyclable materials from home.
- Divide students into groups to write and illustrate a story
about a type of virus or bacterium, what infection it causes,
the symptoms of the infection, and how it is transmitted.
Words to Share
- Acidophilus
- Antibiotic
- Bacteria
- Electron microscope
- Fermentation
- Fungi
- Germs
- Microbe
- Microorganism
- Optical microscope
- Penicillin
- Virus
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