Did you know you could turn milk into plastic? I didn’t. I had no idea!
I did know that you can turn cream into butter, which is just what I was planning on doing with one of my Kindergarten classes back when I taught in the classroom. We love easy science experiments!
There I was, armed with gallons of cream (which, as it turns out, was waaaay more cream than needed), when one of my lovely colleagues said, “Oh! Are you making plastic?”
I looked at her as if she were insane and said, “No… this is cream.”
She then smiled and said, “Oh, I thought it was milk,” and started to walk away.
As if you could walk away after a sentence like that! I quickly chased after her and got all the details on how to turn milk into plastic. Turns out—she’s not insane! You really can! And best of all, you only need to add vinegar.
Before we get into it, you’ll also want to grab your FREE Printable Instructions! Little ones will love being able to follow along, helping with each step as they take part in this experiment:
Good news, friends, I have worked out all the kinks, done this science experiment more than a few times (it’s that awesome), and have all the details just for you. This is such a great STEM activity for kids!
How to Turn Milk into “Plastic”
You can turn milk into “plastic” in literally minutes with only milk and vinegar and a few kitchen supplies—and it is awesome.
- 1 cup whole milk
- 4 tbsp vinegar
- microwavable bowl or a saucepan
- mixing bowl
- paper towel
- cookie cutters
- food coloring, optional
Step 1: Heat the Milk
First, take 1 cup of milk and warm it in the microwave for about 1.5 minutes, or slowly heat it in a pot on the stove (you want the milk hot but not boiling).
Step 2: Add Vinegar and Stir
Next, stir in 4 tablespoons of vinegar. The milk will start to clump as the acid in the vinegar breaks down the protein in the milk. Stir for about 1 minute.
Step 3: Strain the Liquid
Strain the milk through a strainer. All the clumps will stay in the strainer—really push on them to get all the liquid out.
Step 4: Shape and Color
Finally, transfer it to some paper towels and continue to press all the liquid out of the plastic milk. You can add a few drops of food coloring if you’d like, or leave it white—we’ve done both! Then shape the “plastic” by pressing it into a cookie cutter.
I flipped our cookie cutters over so you could get a better look at how it compresses in the photo below (we opted to keep these little stars white).
Step 5: Let Dry and Display!
Set them aside to dry for a good long while—it could take a couple of nights, or you can pop them in the fridge to help them harden a bit faster—then they’re ready! Once they’re hardened, they are ready to be hung up in a window, on a door, or used to decorate a Christmas tree!
My kids just loved this science experiment; I hope yours will, too!
So this is the takeaway lesson here, friends: If someone says something that doesn’t make sense, chase them down the school hallway and ask questions! You might just discover the coolest science experiment of all time.
*** Goodness gracious! I had no idea this post would elicit quite so much discussion. I can certainly say I have learned a ton reading through the comments below. If you are looking for more information about the science behind this process or about the making of paneer, please read the comments on this post.***
If your children enjoy learning and experimenting in the kitchen, they’ll love my Edible Science Family Unit Study! It is full of delicious, hands-on activities—from learning about states of matter while making popsicles, to discovering how harvested cacao pods become chocolate while making some delicious chocolate-dipped cookies.
Check out Edible Science!
Thank you so much for reading, my friend!