This post is part of the 31 days of creative STEM activities for kids series.
For today’s version of science experiments for kids, we decided to go classic with the bread mold experiment.
Although not as flashy as some of our other classic science fair projects, it was probably more educational than some others.

Monkey enjoyed seeing how long it took for mold to grow on various forms of bread.
Don’t miss the complete list of Halloween science experiments!
The Bread Mold Experiment
Follow along with these instructions to make your own version of the bread mold experiment!
Bread mold science project science:
Our experiment was simple. We placed bread in various conditions (we had dry dark, dry light, wet, open, and in a closed bag) and Monkey came up with a hypothesis for which piece of bread would mold first.
She predicted it would be the bread we placed in the paper bag in the pantry.
Bread mold science fair project directions:
What you will need for the bread mold experiment:
- Bread (fresh bread from a bakery will produce much faster results than bread with preservatives)
- Various bags
- A permanent marker to label each piece of bread
How to set up a bread mold science fair project
Divide your bread into as many pieces as you want to test. We used around five pieces.
We only put water on one of our bread pieces, but for the best “scientific” results, you should put water on one piece in a dark place and one in a light place.
In all, we had:
- Bread in a plastic bag in the light
- Bread in a plastic bag in the dark
- Bread in a paper bag in the dark
- Bread on a paper plate with no bag
- Wet bread in a plastic bag
Monkey thought the dry bread in the paper bag would mold first.
You can take this project further by measuring how much mold is on each piece of bread after a certain number of days.
We just wanted to see which bread piece would mold first, so we did not do any mold measuring.
Bread mold experiment results
It took about two days for the first mold to show up- which was on the wet piece.
We waited weeks for any mold to show up on any of the other pieces, but it didn’t. This is why we recommend using fresh bread without preservatives.
We finally gave up on waiting for any more mold to grow and threw it out.
Monkey was surprised that the wet bread grew mold first, but she thought it was interesting that mold grows faster in damp, warm conditions.
We had the bread sitting under a light, which probably sped the molding process.
Find more easy science experiments in the 31 days of STEM activities for kids series!