In this science experiment we will make a Mold Terrarium. The science of mold is fascinating. We will
use a jar with a lid and leftover food to make our creation. Also see bread mold science experiment at
the bottom. Lets do the Mold Science Experiment.
- A clear container with a lid. (Big glass jars and clear plastic containers work great, but you'll have to
throw away the container when you're through, so check with a grown-up about what you can use.)
- Adhesive tape
- Some leftover food (you can use whatever is in your refrigerator), such as bread, fruit (like oranges,
lemons, or grapes), vegetables (like broccoli, zucchini, or green pepper), cheese, and cookies or cake
This Is Important! DO NOT use anything with meat or fish in it--after a few days, these would start to
smell very, very bad.
Process Mold Science Experiment
1) Ask a grown-up for 4 or 5 different pieces of leftover food. If the food is small-a grape or one section of
an orange-use the whole thing. Cut bigger foods like bread or cheese into 1-inch chunks.
2) Dip each piece of food into some water and put it into your container. If you use a big jar, lay it on its
side. Try to spread the pieces out so that they are close to each other, but not all in a heap.
3) Put the lid on the container. Tape around the edge of the lid to seal it.
4) Put the container in a place where no one will knock it over or throw it away. You may want to label it
When most foods get moldy, it means they aren't good to eat any more. But some cheeses are eaten
only after they become moldy! Blue cheese gets its flavor from the veins of blue-green mold in it. When a
blue cheese is formed into a wheel, holes are poked through it with thin skewers. Air gets into these
holes, and a very special kind of mold grows there as the cheese ripens.
5) Every day, look at the food in your Mold Terrarium. For the first 2 or 3 days, you probably won't see
much. But soon you should see blue or green or white fuzzy stuff growing on some of the pieces of food.
6) After a few more days, some of the food in your mold terrarium may start to rot and look really gross.
You can watch how the mold spreads and how things rot for about 2 weeks. After that, it'll get boring,
because not much more will happen.
Here are some things to notice in your mold terrarium:
What food started getting moldy first?
What color is the mold? How many different colors do you see?
What texture is the mold--flat, fuzzy, bumpy?
Does everything in your Mold Terrarium get moldy?
Does mold spread from one piece of food to another?
Do different kinds of mold grow on different types of food?
When you're through with your Mold Terrarium, throw it in the garbage. Don't reuse the container. Don't
even open the lid! Mold is not a good thing for some people to smell or breathe.
What is mold, anyway?
That fuzzy stuff growing on the food in your mold terrarium is mold, a kind of fungus. Mushrooms are one
kind of fungus; molds are another.
Unlike plants, molds don't grow from seeds. They grow from tiny spores that float around in the air.
When some of these spores fall onto a piece of damp food, they grow into mold.
Green plants are green because they contain a chemical compound called chlorophyll. Chlorophyll
makes it possible for green plants to capture the energy of sunlight and use it to make food (sugars and
starches) from air and water. Unlike green plants, mold and other fungi have no chlorophyll and can't
make their own food. The mold that grows in your mold terrarium feeds on the bread, cheese, and other
foods. The mold feeds itself by producing chemicals that make the food break down and start to rot. As
the bread rots, the mold grows.
Ick! Who wants this stuff around?
It can be annoying to find moldy food in your refrigerator. But in nature, mold is a very useful thing. Mold
helps food rot, which is an icky but necessary thing. In a natural environment, rotting things return to the
soil, providing nutrients for other plants. Mold is a natural recycler.
Why does the mold on different foods look different?
There are thousands of different kinds of molds. One mold that grows on lemons looks like a blue-
green powder. A mold that grows on strawberries is a grayish-white fuzz. A common mold that grows on
bread looks like white cottony fuzz at first. If you watch that mold for a few days, it will turn black. The tiny
black dots are its spores, which can grow to produce more mold.
Why didn't some foods get moldy?
If you used foods that contain preservatives, mold may not have grown very well on them. If you want to
experiment more with mold, you can make one mold terrarium using food with preservatives (like a
packaged cupcake) and another using food that doesn't have preservatives (like a slice of homemade
cake). Which one grows more mold? You can also experiment with natural preservatives like vinegar
and salt. If you do more experimenting, let us know what you discover!
Bread Mold Science Experiment
Bread mold will grow at a slower rates in cold temperatures than at warm temperatures.
15 Pieces white bread
15 Zip-lock™ bags
15 pieces of grid film
Rhizopus Stolonifer mold spores
1 freezer set to -5 degrees C. (temp A)
1 refrigerator set to 5 degrees C. (temp B)
1 room kept at about 20 degrees C. (control)
1 clean knife to slice the bread
1 clean cutting board
1 dust or painters mask
Procedure Mold Science Experiment
1. Buy or bake bread, gloves, dust mask, order bread mold
2. Incubate mold for seven days.
3. 5 labeled A, 5 labeled B, and 5 labeled C.
4. Label A bags 1-5 label B bags 1-5 label C bags 1-5
5. Thoroughly clean working area.
6. Cut bread into 11 by 5 centimeter squares making sure that there is no crust on any part of the pieces.
7. Inoculate bread pieces with mold spores using a sterilized needle.
8. Place each piece of bread in a separate Zip-lock™ bag
9. Place bags in the controlled temperatures:
Group A at room temp,
Group B in the refrigerator
Group C in the freezer.
10. Check each piece every twenty-four hours and trace mold pattern on grid film and count the number
of square centimeters the mold covers.
11. Transfer data from grid film to project log.
12. Repeat steps 7 and 8 for ten days
13. Average the amount grown.
The mold in the freezer did not grow at all. Refrigerated mold grew a little. Mold at room temperature
grew the most.
Now get some friends and do your own Mold Science Experiment!
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