Can Oil And Water Mix?

By Melissa Shrader Editor Publisher Loveland Macaroni Kid March 7, 2021

Can Oil and Water Mix? 

Have you ever tried to mix oil and water? 

Let's give it a try!

You'll need:

  • A container that holds 1 1/2 cup's fluid 
  • Something to stir with (we used a metal straw but a spoon would be great too) 
  • Food coloring any color you choose
  • Measuring cup
  • A dish for any overflow just in case there is a lot of wild mixing.

So now we can get started: 

Make a guess of what you think will happen. This is called a hypothesis. Do you think oil and water will mix? 

  • Take 1/2 cup oil and pour it into the container 
  • Now take 1/2 cup water and gently pour it into the container

Take a look at what happens. 

Does the oil stay on the bottom? 

No! It rises to the top. Why? Water and oil have different densities. Water has more density than oil so the oil will float on top. 

  • Now take a moment and add your food coloring.

 When you drop it in watch what happens to the drop? 

It will hang around at the bottom of the oil line and rest there for a bit and stay in the same shape as it went into the oil, round. There is a tension at the top of the water which will take a moment for the food coloring to drop through. 

When it does watch how it reacts with the water.  

The drop will expand and grow. 

  • Now stir it up! Make sure it's very mixed. Now, wait. 

Let's see if it stays mixed or if it separates?

So, It separated right? 

Let's try a trick to see if we can help Oil and Water Mix.

  • You can use the same mixture or create another to place side by side.
  • Do all the steps above BUT just before you mix the oil and water add a drop or two of liquid dish soap. 
  • Now mix like crazy (well have fun but don't get too messy)! 

Does it stay mixed or does it separate?  

Let it sit for a bit, and see if it separates like the first mixture?

You should see 3 layers. 

We will start from the bottom up.

Layer 1 will be some water. 

Layer 2 will be a mixture of water oil and soap

Layer 3 will be suds

So the answer is no, you can't get oil and water to mix (intermolecular polarity) unless you get the help of an emulsifier like soap. The emulsifier helps the molecules interact together.

What does soap do? 

Well, it basically, coats on the oil, and then the water surrounds the soap. It creates layers that help the molecules of the oil and water, able to interact with each other. 

Imagine the oil putting on a sweater and then layering it with a raincoat.  

So Did you come to the same conclusion I did? Did you learn something new?