This is my favorite science project! Disney’s Tomorrowland film originally sponsored this post – but in the years since this was originally published, it’s simply become a staple science experiment for my preschool class and a well-loved science project for science fairs. For the last seven years this simple question ” Which food will rot first?” has been a great way to get preschoolers excited about science and spark their curiosity. That is our goal when including science experiments in our classrooms.
Easy Science Project
Ready? This is so much fun, and I like that it takes days to progress and observe. This gives children a real sense of what being a scientist is like. It takes time to observe and gather info!
Gather your materials. You will need some food (we chose cheese, milk, bread, and an orange slice), something to observe them in, like these test tubes or regular sandwich bags will work, and an observation log. You can find plastic test tubes like the ones I have here – use my amazon affiliate link to buy. 
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Pop the food in and make predictions. We all thought the milk would rot first. This is what I love so much about this science project it gives children a real sense of the scientific process. 
Observe and make notes of the observations on your log for 5 days.
This is what ours looked like on day 1 and day 5. Even though you can see mold on the orange, the milk was nearly solid. As my kids found out, it was very sour. They were very into carefully inspecting and observing each day. One day my daughter shook the milk…don’t. Trust me. For the sake of science, though, we went for it.
The best part of this was how seriously they took their roles as scientists, and I loved making them realize that they don’t have to wait until they grow up to be a scientist, they can be a scientist today.
Need more simple science activities and science experiments for young children?
Check out our tried and true science experiments – these all make great science projects for science fair too! Read the full list here.
Tiffani Godwin says
This is a great idea for my child’s project
Abby says
What do you do with the observation log? Do put a check mark in it or write about what each one looks like.
Allison McDonald says
Depends on the child’s level of understanding – you could make happy or sad faces or a word to describe what is happening, check marks if they are molding and x if they are not. In our house we described the food ” Looks dry” “Getting moldy”. I hope that helps!
Ciara Franco says
This works amazingly! My daughter did it for her STEM and she loved doing this project! I totally recomened this to people who need an idea for STEM! She had so much fun doing this hands-on project!
Allison McDonald says
I am thrilled to hear it was a success!
doggo says
yea it was really fun!
Mikah Wheeler says
It was really fun!!!!!