Science Buddies: "Ask an Expert"

My son has been doing preliminary work on a science experiment involving testing various sources of water for the presence of microorganisms. His plan is to use sterile pipettes to collect water samples from our tap, filtered refrigerator water, swimming pool, commercial bottled water, and as a control, sterile water. After introducing the water to the blood agar Petri dishes and pouring out the excess, he had planed to secure the lids with rubber bands and place the dishes in his home- made incubator which maintains a temperature of approximately 98 degrees F. Observations of any growing cultures will be made with the lids remaining securely on the Petri dishes. At the conclusion of his experiment, I plan to have him observe safe sterilization and disposal of the Petri dishes. At no time during this experiment will the lids to these dishes be removed.

Unfortunately, he has encountered major objections from the school system concerning the culturing of unknown bacteria. My son has already put a great deal of time and work into this project, and I do not want to have this wonderful learning opportunity about which he is so enthused become a frustrating and negative experience (as well as having to start a different experiment after investing over $200 in supplies and educational material). As a safety measure, I have purchased a product called Petri-Seal which, according to the company, will provide an air-tight seal around the Petri dishes.

I am hoping to obtain some information in order to present an argument to the "Powers That Be" in the school system for allowing my son, as well as other students, to explore the fascinating world of microbes in a safe way. It would be a huge disservice to the students, and the field of science in general, to enforce a "blanket" ban on performing any microbiological experiments. It is an area of science which is so conducive to sparking the interest of students.

I am hoping that someone will be able to provide answers to a few questions:

1.) Are there any documented cases of students being harmed as a result of culturing microorganisms for a school science project?
2.) If so, what were the circumstances and were any safety precautions used?
3.) What are the approximate chances of ending up with a culture of pathogenic bacteria when performing an experiment in testing water as my son plans to do? In addition, what would the chances be of inadvertently culturing a pathogenic bacteria from the indoor air?
4.) If pathogenic microorganisms are inadvertently cultured in blood agar Petri dishes in which the lids remain secured, what are the chance of these microbes causing harm (assuming they are properly disposed of)?
Answers to these questions and any other helpful information would be GREATLY appreciated.

Hi,

Any unknown bacterium grown on an agar plate is potentially pathogenic; however, with adult supervision and general safety precautions, including sterilizing the agar plates at the end of the experiment, I believe that this type of work can be done safely. In fact, I have done many microbiology projects with elementary students, primarily 5th and 6th graders. The Science Buddies website has lots of information on this topic, including safety precautions.

https://www.sciencebuddies.org/science- ... fety.shtml

The water samples your son is planning to test are unlikely to contain pathogens. I have many years of experience in working with children and judging science fairs, and I have not heard of any problems associated with children doing microbiological experiments. However, there may have been an incident in your school district that has inspired the new rules. There has been a general trend to impose more restrictions on biological science fair projects and I have noticed that my local science fair, which used to have more entries in the biology area, has shifted to predominantly physical science projects.

To make your son’s project a little safer, you could consider switching to nutrient agar rather than using blood agar, which is the traditional medium for growing pathogens. Also, you will find that water bacteria will actually grow better at 30 degrees Centigrade, rather than 37 degrees (98 degrees F)

However, my opinion will not help if doing microbiological science projects is forbidden by your school district. Your local Scientific Review Committee can review this project to ensure the safety of the project and I would encourage you to check with this committee if you have not consulted with this group. And students should never start on a science project unless it is approved by the teacher; this is always a critical step for a number of reasons.

https://www.sciencebuddies.org/science- ... _src.shtml

You have a couple of options on this project. You could ask again and make sure there has not been a misunderstanding about microbiological projects. Is the problem with your son’s project was the plan to use blood agar, or do the rules state that no microbes at all can be grown? What about bread mold projects? What about bread yeast? What about photosynthetic halophiles? What about Bacillus thuringiensis (insect pathogen)? What about a yogurt project? What about the moldy cheese in the refrigerator? Would a microbial fuel cell project be permissible? What about a composting project?

Since you have purchased the materials, your son could go ahead and complete the project and you can ask if a non-approved school project can be entered into the local science fair. However, if a science project is a class requirement for your son this year, he will need to check through the Science Buddies website and select a new topic.

https://www.sciencebuddies.org/science- ... deas.shtml

If this happens, it will be your job to put the project disapproval into perspective and display a completely positive attitude. You do want to ensure that your son has a positive experience in doing his science project, even if he has to start over again.


I hope this helps.


Donna Hardy

Hi Bill,

Just in case your son has to switch to a different topic, I thought I would share one of my favorite microbiology experiments from the Science Buddies website. This project requires some really fresh cow manure, some kitchen trash, balloons and empty soda bottles. It is a microbiology project and involves growing anaerobic bacteria to produce methane gas. It always seems to work well and is perfect for elementary students. Since your son is interested in microbiology, I think he would really enjoy this one.

https://www.sciencebuddies.org/science- ... p027.shtml

I have not heard of a school district as restrictive as yours for microbiology projects, so you will still have to check with your son's teacher to get approval if he does choose this one.

Donna Hardy