Science Fair Project: Which Foods Do Molds Love Best?
Need a science fair project to impress your teachers and amaze your friends—and maybe even win a ribbon? Here is one of our favorites, which answers the question: Which foods do molds love best? In this experiment you’ll learn that some molds grow better on some foods than others, and that various factors contribute to their growth. The project takes a little time and patience, but the outcome is worth it. Here’s how you do it.
What Do You Think Will Happen?
In this experiment, you’ll be putting three bags of different foods in five different growing environments within your own house (dry and dark, cold and dark, moist and warm, brightly lit, dark and damp, etc.). You’ll then take daily observations of the food in all of the bags to see how the mold grows.
Before you start the experiment, you need to come up with a hypothesis, or a guess about what will happen. Do you think that the foods you keep in a dresser drawer will get as moldy as those stashed in the bathroom?
Locate different environments within your home to determine where mold grows best.
Think about where you may have observed molds and fungi in your home. Are there particular areas where you’ve noticed mildew or a moldy smell? If so, consider that when you’re making your hypothesis. And think about what foods you may have seen molds growing on in the past. What similarities were there in those foods? Were they all kept in the refrigerator? Were they foods that had been sitting around the kitchen for a while because nobody liked them, or food that had already been cooked?
Some foods are more hospitable to molds than others, and molds grow better in some environments more than others. In your experiment, you’ll be working to determine which foods molds grow best on, and in which environments.
Consider all the information you may already know. Then you can make an educated guess about the results of your experiment.
Materials You’ll Need for This Project
The materials you’ll need for this project are minimal and easy to get. They are as follows:
- Five slices of bread (You can use any type of bread you have available, but all five slices should be the same.)
- Five slices of orange
- Five slices of cheese
- Fifteen zipper-lock sandwich bags
- One permanent marker
You don’t necessarily need to put a whole piece of bread or an entire piece of cheese into each bag. A half piece will do just fine. And you should be able to get five slices out of a single orange.
Conducting Your Experiment
Follow these steps to conduct your experiment:
- Using the permanent marker, label five bags “bread.”
- Label five bags “orange slice.”
- Label five bags “cheese.”
- Place a piece of bread into each of the appropriately marked bags.
- Place a piece of orange into each of the appropriately marked bags.
- Place a piece of cheese into each of the appropriately marked bags.
- Securely close and seal each bag.
- Select one bag containing bread, another containing an orange slice, and another containing cheese. Group these three bags together as SET 1.
- Repeat Step 8 to make four more sets of each food.
- Place each set of three bags in a location of your home that has a different growing environment.
- Using the permanent marker, label each bag with its location. Each set of three bags will have the same location marked on the bag.
- Observe each bag once a day for two weeks. Try to look at the bags at about the same time each day in order to allow fairly equal growth time. Record everything you notice about the contents of each of the 15 bags on a chart like the one in the next section, “Keeping Track of Your Experiment.”
- At the end of two weeks, place all of the sealed lunch bags in the kitchen trash bag. Mom won’t be at all happy with you if you leave bags of moldy food lying around.
It’s very important that you make daily observations during the course of your experiment. The next section will show you how to keep track of those observations.
Keeping Track of Your Experiment
You can make your own charts to keep track of what occurs during your experiment, or you can download the charts in this guide as a printable PDF here.
Use one chart to keep track of what happens during the first week, and another for the second week.
Keeping track of mold growth for the first week.
Be sure to write down as many observations as you can each day. If you see a bit of mold growing on one piece of bread, for instance, and a lot of mold growing on another, be sure to note the location of the breads, the amount of mold and what it looks like, and anything else you might see.
Don’t wait until the next day, or even later the same day, to write down what you see. Take the chart with you from room to room and write down what you see as you look at each bag.
Keeping track of mold growth for the second week.
Putting It All Together
Once you’ve got all your observations recorded on a chart or charts, you’ll be able to look closely at what you’ve written and summarize what you’ve learned from your experiment.
When you’ve put together your results, you’ll be able to see whether your hypothesis was correct. You will have reached a conclusion, which is the last step of the scientific method. When you reach a conclusion, you will have solved the problem you described at the beginning of your project.
Whether or not your results turned out to be what you thought they would is not the most important aspect of a science fair project. Having conducted the experiment correctly and recorded your results properly is more essential than a correct hypothesis. For more fun science projects, check out our Quick Guides Science Fair Project: Do Clouds Tell Us What Weather Is Coming? and Science Fair Project: Can a Visible Light Outshine Infrared Radiation?. Happy experimenting!
From The Complete Idiot’s Guide to Science Fair Projects by Nancy K. O’Leary and Susan Shelly
