Rainbow Milk ExperimentRainbow Milk Experiment

I am so excited to be working with some fabulous bloggers to bring you Saturday Science Blog Hop and Linky Party!!  This is my first week participating so check out the bottom of this post for links to some other great science projects and link up your own if you have any.

Last week my son had Rainbow week in Kindergarten and we brought Fruity Rainbow Crispy Treats and Rainbow Fruit Snacks.  And to end their week of learning about rainbows they did a Rainbow Milk Experiment and my 5-year-old was so excited to tell me all about it and try it at home.

He had a handwritten note of all of the supplies we needed and it included a pie plate, Whole Milk (it has to be whole), food coloring and liquid dish soap.

Rainbow milk experimentFill the pie plate with milk and add a few drops of food coloring around the edges.  I let my son decide where we put the food coloring and how much we used.  He was thrilled to be in charge. 🙂

Rainbow milk experimentNext add a few drops of dish soap into the middle of the dish and watch the colors dance and the rainbows appear.

Rainbow Milk Experiment


I’ve seen this experiment done by just adding a cotton swab dipped in dish soap and holding it in the middle as well.  You will get slightly different results but since my kindergartener was in charge of our experiment he added as much dish soap as he could. 😉 I plan on trying it with a cotton swab to compare the results to what we got by just adding the dish soap.

Rainbow milk experiment

The longer we waited, the more the colors mixed until they were completely mixed throughout the plate.  Once we had the results that they were happy with, my boys decided to draw their results so we got out the crayons and they had fun drawing their experiment.

Rainbow milk experimentI am going to be adding a video soon, because you really have to see this experiment to see how cool it is.

So, how does this happen?  If you think about dish soap, what is it that dish soap is supposed to do?  It is supposed to break down fat, right?  We’ve all seen the television commercials where the dish soap breaks down all sorts of grime without you even having to scrub (which never works as well in real life as it does on the screen. Am I right? Yep.)  Well, the same sort of thing is happening in this experiment.  The dish soap is grabbing on to the fat molecules in the milk and are pushing and pulling the milk molecules and food coloring around until all of the fat from the milk has bonded with the dish soap.

There are more scientific explanations to this experiment but since we are keeping things simple, we can just say that the dish soap loves to gather up all of the fat in the milk and the fat is attracted to the soap causing the colors  You can add a drop or two more of dish soap until the movement stops and you know that all of the fat molecules have bonded with the soap.

We had a lot of fun sharing this experiment and for more fun, make sure to check out our other Simple Science projects.


Time for Saturday Science Blog Hop Link Up!

Please visit all the blogs below, make sure to follow us and link up your science experiments in the link up below!

What Can the Wind Do? from Stir the Wonder

Easter Egg Races: Exploring Angles of Ramps, Gravity & Motion from Little Bins for Little Hands

What is Science? from Lemon Lime Adventures

Surface Tension from Suzy Homeschooler