Germ Invasion

Recommended Project Supplies
Get the right supplies — selected and tested to work with this project.
View Kit
Difficulty
Time Required Average (6-10 days)
Material Availability A kit for this project is available from our partner Home Science Tools.
Cost Average ($40 - $80)
Safety Follow the safety precautions for handling microorganisms listed in the Procedure.

Abstract

Microbes are everywhere in our environment, but for the most part they escape our notice. This project shows you how to safely culture and study common bacteria from your everyday surroundings.

Objective

In this science project you will determine the microbial diversity present in your own everyday environment. Of the 100 million or so bacteria that are proposed to exist, how many distinct species can you identify? How can these different species be identified: By size, shape color, growth rate?

Share your story with Science Buddies!

I did this project Yes, I Did This Project! Please log in (or create a free account) to let us know how things went.

Credits

Laurie Usinger, Bio-Rad Laboratories
Images courtesy of Bio-Rad Laboratories

Cite This Page

General citation information is provided here. Be sure to check the formatting, including capitalization, for the method you are using and update your citation, as needed.

MLA Style

Science Buddies Staff. "Germ Invasion." Science Buddies, 20 Nov. 2018, https://www.sciencebuddies.org/science-fair-projects/project-ideas/MicroBio_p007/microbiology/germ-invasion. Accessed 23 July 2019.

APA Style

Science Buddies Staff. (2018, November 20). Germ Invasion. Retrieved from https://www.sciencebuddies.org/science-fair-projects/project-ideas/MicroBio_p007/microbiology/germ-invasion


Last edit date: 2018-11-20

Introduction

Microorganisms are the most fundamental, diverse, and prevalent biological organisms that inhabit the earth today. Prokaryotic microorganisms, organisms without a nucleus, can be generally divided into three classes: bacteria, protozoa, and fungi. By far the most predominant of these three classes of organisms are bacteria, single celled organisms which inhabit every type of environment on earth, and which have been in existence for greater than 3.5 billion years. Bacteria are ubiquitous, and are found in almost any environment. They thrive in the hot environments of deep sea sulfur vents, the frozen tundra of the Antarctic, the saline environments of the Dead Sea, and even extremely acidic environments such as the stomachs of organisms. In this science fair project, you will investigate what kind of bacteria, and how much bacteria, grows in different locations around your home.

Bacteria can be both pathogenic, responsible for a variety of diseases, and non-pathogenic, or harmless. Pathogenic bacteria are responsible for outbreaks of diseases like cholera, tuberculosis, and food poisoning. In contrast, non-pathogenic bacteria have many roles, including helpful ones! Some non-pathogenic bacteria lives in the stomachs and intestines of humans helping to break down foods and produce necessary nutrients such as Vitamin K. Moreover, a variety of naturally occurring antibiotics are synthesized from bacteria, such as streptomycin.

What kind of bacteria do you think live around your home? Try this science project to find out!

Terms and Concepts

Any basic biology text will have a chapter on prokaryotic organisms. Begin by reading a text on basic microbiology, such as Chapter 16 in Biology, Exploring Life, by Campbell, Williamson, and Heyden. Topics and terms which should be researched include:
  • Prokaryote vs. eukaryote
  • Gram-negative vs. gram positive bacteria
  • Pathogenic vs. non-pathogenic bacteria
  • Bacterial motility
  • Phototrophs vs. autotrophs vs. chemotrophs vs. heterotrophs
  • Anaerobic vs. aerobic bacteria
  • Symbiotic bacteria and their importance to higher organisms
  • Bacteria, and E. coli, as scientific research tools

Bibliography

Visit these websites for an introduction to bacteria:

News Feed on This Topic

 
, ,
Note: A computerized matching algorithm suggests the above articles. It's not as smart as you are, and it may occasionally give humorous, ridiculous, or even annoying results! Learn more about the News Feed

Materials and Equipment Product Kit Available

  • Bacteria Discovery Kit, available from our partner Home Science Tools. Needed from the kit:
    • Nutrient agar plates (24)
    • Disposable gloves (2 pairs)
  • You will also need to gather these items, not included in the kit:
    • Permanent marker
    • Heavy-duty tape or saran wrap
    • Bleach
    • Lab notebook

Disclaimer: Science Buddies participates in affiliate programs with Home Science Tools, Amazon.com, Carolina Biological, and Jameco Electronics. Proceeds from the affiliate programs help support Science Buddies, a 501(c)(3) public charity, and keep our resources free for everyone. Our top priority is student learning. If you have any comments (positive or negative) related to purchases you've made for science projects from recommendations on our site, please let us know. Write to us at scibuddy@sciencebuddies.org.

Recommended Project Supplies

Get the right supplies — selected and tested to work with this project.
Project Kit: $69.95
View Kit

Remember Your Display Board Supplies

Artskills materials poster making kit

Poster Making Kit

ArtSkills buy now button
ArtSkills supplies trifold

ArtSkills Trifold with Header

ArtSkills buy now button
ArtSkills supplies poster lights

Poster Lights

ArtSkills buy now button

Experimental Procedure

Working with Biological Agents

For health and safety reasons, science fairs regulate what kinds of biological materials can be used in science fair projects. You should check with your science fair's Scientific Review Committee before starting this experiment to make sure your science fair project complies with all local rules. Many science fairs follow Intel® International Science and Engineering Fair (ISEF) regulations. For more information, visit these Science Buddies pages: Projects Involving Potentially Hazardous Biological Agents and Scientific Review Committee. You can also visit the webpage ISEF Rules & Guidelines directly.

  1. Identify 7 different locations where you would like to assess microbial biodiversity. Suggested sites could include the bathroom, kitchen, locations near heating vents, bedrooms, the refrigerator, the backyard, the garage, etc.
  2. At each site, place 3 nutrient agar plates. Use the permanent marker to label the bottom of each plate with its location. Leave the plates open and exposed for 3 hours.
  3. An additional 3 plates should be unopened and used as negative controls. In other words, you will study what grows on these plates even though you never expose them to the air. Hopefully, very little if anything will grow! Use the permanent marker to write "negative control" on the bottom of each of these plates.
  4. At the end of 3 hours, collect all the plates. Seal each plate with heavy-duty tape or saran wrap.
  5. Allow the plates to incubate by placing all of them in one single location that has a fairly constant room temperature (about 22 degrees Celsius) for 7-10 days, until distinct bacterial colonies can be observed. (Don't forget to put the 3, unopened control plates in this same location.)
  6. Collect data over the course of the experiment. Every other day, write down the number of colonies, the color, and the size in your lab notebook.
  7. After the end of the three week period, make various graphs of the data. Suggestions include, but are not limited to:
    1. Colony count on each plate.
    2. Colony count at each location (take an average of the 3 plates).
    3. Different types of microorganisms, based upon:
      1. Size
      2. Color
      3. Shape
  8. Keep the microbial plates until your science project is completely done, and while you are writing up your display board or other assigned summary. You will want to make many observations.

Discussion Points to Consider When Writing up the Conclusions of your Science Project

  1. Which environmental areas resulted in the most microbial growth?
    1. What environmental features unique to those locations might lead to microbial growth?
      • Moisture content?
      • Air circulation?
      • Cleanliness?
  2. Based upon your background reading, can you identify any of the bacterial/microbial colonies based upon their morphological features? Tip: The Science Buddies guide to Interpreting Plates should be helpful.
    1. Color?
    2. Shape?
    3. Size?
  3. If you had access to reagents in a biology laboratory, how could you use more sophisticated methods to type, classify, and characterize the individual colonies?
  4. Based upon your background reading, what percentage of the microbial organisms that are present in your environment did you isolate and identify?

Bacterial Safety

Bacteria are all around us in our daily lives and the vast majority of them are not harmful. However, for maximum safety, all bacterial cultures should always be treated as potential hazards. This means that proper handling, cleanup, and disposal are necessary. Below are a few important safety reminders.

  • Keep your nose and mouth away from tubes, pipettes, or other tools that come in contact with bacterial cultures, in order to avoid ingesting or inhaling any bacteria.
  • Make sure to wash your hands thoroughly after handling bacteria.
  • Proper Disposal of Bacterial Cultures
    • Bacterial cultures, plates, and disposables that are used to manipulate the bacteria should be soaked in a 10% bleach solution (1 part bleach to 9 parts water) for 1–2 hours.
    • Use caution when handling the bleach, as it can ruin your clothes if spilled, and any disinfectant can be harmful if splashed in your eyes.
    • After bleach treatment is completed, these items can be placed in your normal household garbage.
  • Cleaning Your Work Area
    • At the end of your experiment, use a disinfectant, such as 70% ethanol, a 10% bleach solution, or a commercial antibacterial kitchen/bath cleaning solution, to thoroughly clean any surfaces you have used.
    • Be aware of the possible hazards of disinfectants and use them carefully.

Explore More!

Interested in the science behind viral outbreaks? Check out Zika Virus.

If you like this project, you might enjoy exploring these related careers:

female microbiologist looking in microscope

Microbiologist

Microorganisms (bacteria, viruses, algae, and fungi) are the most common life-forms on Earth. They help us digest nutrients; make foods like yogurt, bread, and olives; and create antibiotics. Some microbes also cause diseases. Microbiologists study the growth, structure, development, and general characteristics of microorganisms to promote health, industry, and a basic understanding of cellular functions. Read more
Agricultural technician evaluating a plant

Agricultural Technician

As the world's population grows larger, it is important to improve the quality and yield of food crops and animal food sources. Agricultural technicians work in the forefront of this very important research area by helping scientists conduct novel experiments. If you would like to combine technology with the desire to see things grow, then read further to learn more about this exciting career. Read more
Inspector examining turkeys

Agricultural Inspector

Who works to protect the public health from food-borne illnesses? Agricultural inspectors. Everyone needs to eat, and agricultural inspectors work to ensure the quality and safety of the food supply to determine if they are in compliance. They also inspect farms, businesses, and food-processing plants to determine if they are in compliance with government food regulations and laws. Read more


Share your story with Science Buddies!

I did this project Yes, I Did This Project! Please log in (or create a free account) to let us know how things went.

Ask an Expert

The Ask an Expert Forum is intended to be a place where students can go to find answers to science questions that they have been unable to find using other resources. If you have specific questions about your science fair project or science fair, our team of volunteer scientists can help. Our Experts won't do the work for you, but they will make suggestions, offer guidance, and help you troubleshoot.

Ask an Expert

Contact Us

If you have purchased a kit for this project from Science Buddies, we are pleased to answer your questions.

In your email, please follow these instructions:
  1. What is your Science Buddies kit order number?
  2. Please describe how you need help as thoroughly as possible:

    Examples

    Good Question I'm trying to do Experimental Procedure step #5, "Scrape the insulation from the wire. . ." How do I know when I've scraped enough?
    Good Question I'm at Experimental Procedure step #7, "Move the magnet back and forth . . ." and the LED is not lighting up.
    Bad Question I don't understand the instructions. Help!
    Good Question I am purchasing my materials. Can I substitute a 1N34 diode for the 1N25 diode called for in the material list?
    Bad Question Can I use a different part?

Contact Us

Related Links

News Feed on This Topic

 
, ,
Note: A computerized matching algorithm suggests the above articles. It's not as smart as you are, and it may occasionally give humorous, ridiculous, or even annoying results! Learn more about the News Feed

Looking for more science fun?

Try one of our science activities for quick, anytime science explorations. The perfect thing to liven up a rainy day, school vacation, or moment of boredom.

Find an Activity