Growing bacteria in a science project can be a fun way to learn how micro-organisms (bacteria, yeasts and fungi) make up a part of every-day life. There are literally hundreds of ways in which you can experiment with bacteria and other micro-organisms at home.
Although we cannot see them with the naked eye, micro-organisms are an important part of our lives. Some examples:
Yeast is used to make bread, beer and wine Lactic acid bacteria are used to curdle milk to make cheese Bacteria can contaminate food and make you sick. Bacteria and fungi can make food go off Micro-organisms are important for the breaking down of sewage and garbage Some micro-organisms can make you sick in many ways. These are called pathogenic organisms. Our bodies are covered with bacteria and our digestive systems are full of bacteria. These bacteria are good and help our bodies to function.
These are a few ideas for science projects:
- What are the places at home where the most bacteria live
- Many dishwash liquids and other cleaning agents have disinfectants in them. Do they actually work?
- Where do bacteria live on the human body and are there different types of bacteria in different places on the body
- Do antibacterial soaps work? Which one works the best?
- Which micro-organisms cause food to off and where do they come from?
- Does jik really kill the bacteria in your toilet?
- What is dirtier, your hands or your mouth?
- Why do you need to shower every day?
- Why does your dog’s breath stink?
- Is your dog’s mouth cleaner than yours?
- Why should you brush your teeth?
- Why should you wash your hands before dinner?
- Insects and the germs they carry
- Bacteria on chopping boards
These are just some ideas. There are plenty more. Just use your imagination. It is best to come up with your own idea and design the experiment yourself. This will help you to score the highest marks for your project.
- Almost all projects involving bacteria are relatively easy to do and you can use the same kinds of tools for all of them.
- Let’s talk about bacteria first. By definition, bacteria are too small to see and that is why you need tools to see them. The easiest way is by growing them on culture media (food for bacteria) until there are so many there that you can actually see them easily. Culture media is usually put into a petri dish and has agar in it. This is a substance made from seaweed. It looks like jelly. The agar has nutrients like sugars and proteins added to it to provide food for the bacteria. The agar cannot be broken down by the bacteria and they grow on the surface and form a “colony”. A colony contains millions of bacteria. The shape, size and colour of the colonies will be different for different types of bacteria. Remember that each colony comes from one bacterium. So, if you put 5 bacteria onto the agar, you will end up with 5 colonies.
- How do you collect your sample (specimen) and how do you transfer (plant) it onto the media? The easiest way is to use a swab. A swab looks like an ear bud. It needs to be sterile so that you know that the bacteria that you grow are from the specimen and not from your swab. Use the swab by wetting it slightly with sterile water and then rubbing it on the surface of whatever you want to test. Then gently rub the swab on the media, taking care not to damage the surface of the agar. This is called inoculating the medium. If you are comparing different surfaces, it is best to rub a new swab on similar areas and then to inoculate the media in a similar way so that you are comparing the same thing.
- Bacteria grow at all temperatures but they will grow best at a temperature slightly above room temperature. Put them in a warm place (on top of the TV or in the kitchen and leave them for one or two days.
- For yeasts and fungi (moulds), you can use exactly the same techniques or media or you can use more specialised media called Sabouraud dextrose agar.
Using these tools it is possible to design any experiment you want. All you need is agar plates, sterile swabs and sterile water. These are all provided in our kit. If you need advice on how to design your experiment, please contact us and we will help you with pleasure.