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Three Cool Science Experiments with Bread Mold

written by: Sylvia Cini • edited by: Amy Carson • updated: 10/25/2013

You've seen them before. Those fuzzy, green-gray spots that show up on food after it's been hanging around your fridge for too long. They look gross, smell worse and ruin any chance you had of enjoying a peanut butter sandwich. However, they do provide the perfect opportunity for some experiments!

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    What Is It?

    Nsr-slika The green stuff on your slice of bread is called mold. Mold is a microscopic, living organism in the Fungi kingdom, related to yeast and mushrooms. Although it can be harmful if handled incorrectly, mold is not a bacteria or virus.

    In the first stage of its life cycle, mold lays dormant as a spore, a reproductive structure that is similar to the seeds of plants. When these spores find a warm, moist, nutrient-rich environment they set up a colony, mature and produce more spores. That's the growth that you see on your food--trillions of mold spores!

    These spores are a constant part of our environment, but they rarely cause health problems. People with sensitive respiratory or immune systems may have an allergic reaction to these background levels of spores.

    Moldy Mandarin Fruit 

    What Are They Doing On My Food?

    Mold spores are everywhere--in the dirt, on doorknobs, on your clothes and in the air. They are spread around by air circulation and through contact with living organisms.

    That's right, YOU are a mold spore bus.

    Mold spores cling to your hair, skin and clothing. Although washing up temporarily decreases the number of spores on your body, it does not prevent you from being exposes to the spores in the environment. It's just a matter of time before the spores settle again.

    But don't worry! Mold is a natural part of our world and it will not do you harm in these small quantities. In fact, some people think mold is pretty tasty.

    Plesn EW! What Foods Are Made With Mold?

    • Soy Sauce
    • Hard Salami and other dried sausages
    • Country Cured Ham
    • Blue Roquefort Cheese
    • Gorgonzola Cheese
    • Stilton Cheese
    • Brie Cheese
    • Camembert Cheese

    Want To See Your Little Neighbors?

    You can get a closer look at the mold that lives in your home by trying out this bread mold science experiment. Start growing your own mold colony today.

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    Experiment #1: Grow Different Kinds of Mold

    Things You'll Need:

    • Bread
    • Water
    • Plastic zipper bag
    • Masking tape
    • Marker
    • Notebook
    • Pen
    • Camera

    Verschimmeltes Brot Bread Mold Science Experiment #1:

    1. Ask permission to conduct this experiement.
    2. Sprinkle water on a slice of bread.
    3. Put the bread in the plastic bag.
    4. Seal the plastic bag.
    5. Tape the plastic bag closed.
    6. Place a small piece of tape in the corner of the bag and label it with today's date.
    7. Stash the plastic bag in a warm place outside of the house where it will be undisturbed for 7 days.
    8. Inform your parents and siblings about your experiment so no one will attempt to throw away (or eat!) your experiment.
    9. Track the growth of your mold by checking it everyday. Write down notes about the size and color of your colony. If you can, take a photograph of the mold each day.
    10. At the end of the experiment, throw away the sealed bag containing the moldy bread. You do not want to be around when the bag opens. Inhaling mold spores is harmful.

    Questions:

    When did the mold first appear?

    What color is the mold? Why is the mold different colors?

    Where on the bread did the mold grow? (e.g., the corner, the middle) Why do you think that is?

    Why do you think inhaling mold is bad? (Hint: Mold loves to grow in warm, moist places and will eat just about anything organic)

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    Experiment #2: Investigate the Effects of Moisture

    Moldy nectarines In this first experiment you made some spores very happy by setting up the perfect environment. There was moisture from the water, warmth from the environment and bread as a food source. What do you think will happen if you change the amount of moisture? Try it to find out!

    Things You'll Need:

    • 3 Slices of Bread
    • Water
    • 3 Plastic zipper bags
    • Metal tray
    • Masking tape
    • Marker
    • Notebook
    • Pen
    • Camera

    Bread Mold Science Experiment #2:

    1. Ask permission to conduct this experiment.
    2. Label the plastic bags "Dry," "Moist" and "Wet." Don't forget to write today's date on the bags.
    3. Place a slice of bread into the plastic bag marked "Dry" without wetting it.
    4. Pick up the second slice of bread and sprinkle it with water.
    5. Put the bread in the plastic bag labeled "Moist."
    6. Wet the third slice of bread over the sink or by dipping it into a bowl of water.
    7. Place the wet bread into the bag labeled "Wet."
    8. Seal and tape all three plastic bags closed.
    9. Place the bags on a disposable, metal tray--the kind you use for cooking.
    10. Stash the plastic bags in a warm place outside of the house where they will be undisturbed for 10 days.
    11. Inform your parents and siblings about your experiment. (You really don't want them touching this one!)
    12. Track mold growth daily. Write down notes about the size and color of your colonies. If you can, take a photograph of the mold each day.
    13. Again, be sure to throw away the sealed bags when the experiment is through.

    Questions:

    Did the amount of moisture affect mold growth?

    Which slice of bread grew the most mold?

    Which grew the least?

    Can you think of a reason more water would prevent/aid the development of a colony?

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    Experiment #3: Investigate the Effects of Temperature

    Things You'll Need:

    • 3 Slices of Bread
    • Water
    • 3 Plastic zipper bags
    • Glass jar
    • Masking tape
    • Marker
    • Notebook
    • Pen
    • Camera

    Bread Mold Science Experiment #3:

    1. Ask permission to conduct this experiment.
    2. Double-up one of the plastic bags. Label this bag "Cold."
    3. Label the other bag "Room Temp."
    4. Place a piece of tape on the side of the glass jar and label it "Refrigerated."
    5. Don't forget to write today's date on all three containers.
    6. Sprinkle an equal amount of water on each slice of bread. (Hint: Use the amount of water that grew mold the best in experiment #2)
    7. Place a slice of bread into each plastic bag and one in the glass jar.
    8. Close the bags and tape shut. Seal the jar and tape around the lid to prevent leakage.
    9. Put the bag labeled "Cold" in the freezer, the bag labeled "Room Temp" in a safe place outside (i.e., the shed) and the jar in the refrigerator. Be sure the jar in the refrigerator is not in direct contact with other food stuffs.
    10. Monitor mold growth over the next 10 days. Write down notes about the size and color of your colonies. Take a photograph of the mold each day.
    11. Even if you do not see mold on the bread, throw away the bags and the jar! Mold is often present even if it is not visible and it is not something you want to breathe in.
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    My Mold Won't Grow!

    I started my bread mold experiments in winter--2/7/11 to be exact. But I didn't see any colonization until APRIL!

    Why did my mold take so long to grow? (HINT: Look at the water droplets on the interior of the bag)

    017 018 020 

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    Keep Thinking...

    In which environment did mold grow the best? The worst?

    What other foods do you think would mold?

    Does the type of bread make a difference?

    What happens if you rub the bread in the dirt before putting it in the bag? the counter? your hands?

    What are mold's favorite foods? When does it grow the fastest?

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    Resources

    Moldy Experiments--Want to try out some more bread mold science experiments?

    Kid Zone: How Does Mold Grow? (http://www.kidzone.ws/science/mold.htm)

    Mold & Health--Find out how mold can affect your health.

    USDA: Molds On Foods (http://www.fsis.usda.gov/factsheets/molds_on_food/index.asp)

    Epidemiology: Mold And Human Health (http://www.epi.state.nc.us/epi/oii/mold/conditions.html)

    Asthma And Allergy Foundation Of America: Mold Allergy (http://www.aafa.org/display.cfm?id=9&sub=16&cont=58)

    More On Mold--Itching for more information about your friendly neighborhood spores?

    CNN: Student Diet (http://articles.cnn.com/2009-08-11/health/food.safety_1_mold-food-items-college-students?_s=PM:HEALTH)

    Florida Solar Energy Center: Mold Growth (http://www.fsec.ucf.edu/en/consumer/buildings/basics/moldgrowth.htm)

    Photo Credits

    • "Moldy Nectarines" by Roger McLassus. Wikimedia Commons
    • "Moldy Mandarin Fruit" by Sapp. Wikimedia Commons
    • "Mold On Bread" by Henry Mühlpfordt. Wikimedia Commons
    • "Mold" by Pawet Wieslaw Kaczorowski. Wikimedia Commons
    • "Dublin Street Mold" by Infrogmation. Wikimedia Commons
    • "Nsr-Slika" by Martin Cilenšek. Wikimedia Commons