Mixing oil and water – science experiment


One of R(3)’s most favourite things to do at the moment is colour mixing. Whenever we play with paint lately, he inevitably has more fun experimenting with mixing the colours than actually putting paint on paper. I thought this little experiment of mixing oil, water and food colouring would really spark his imagination. He had so much fun with this and as usual, his play evolved from our first intention (the science experiment) to something else altogether – fine motor, sensory and imaginative play.

I found the idea for this experiment via this post over at Play Create Explore. Be sure to check them out. Jessie has some fantastic ideas for creative play.

This is so simple to put together. All you will need is water (at room temperature), vegetable oil, and food colouring.

Fill a vessel to about three quarters full with the water. We used a hurricane lamp simply because I wanted to use something large, but a vase, or even a larg drinking glass would work just as well. Next, pour in the vegetable oil. For this to work, you will need the layer of oil to be about two inches deep.

Even this first simple step was so much fun! Watching the oil bead together and drop down into the water, and then float back up to the top of the water was fascinating and very meditative.

We waited until the oil had settled into a single layer above the water.

 Then it was time to add some colour! We added a few drops of food colouring to the oil. At first it seemed as though nothing was happening, until, slowly……


Things really start to explode in there…

Until at last, we ended up with this….



         (or what we learned from doing this experiment twice because it was a great big fail the first time around!)

  • You only need a VERY small amount of food colouring. Just a few drops of each colour. The first time we tried this, we squirted the colouring from syringes and the colour just shot straight through the oil immediately and the water was just a murky mess.
  • The water needs to be at room temperature.
  • The larger your vessel, the thicker your layer of oil needs to be. For the large hurricane lamp that we were using, our layer of oil was approximately three inches thick.
  • Drop in one colour at a time for dramatic effect. Start with your lighter colours first and end with your darker colours, otherwise you won’t see the light colours dropping through. We started with yellow, then followed with red, green and finally blue.

After the colours had started to blend together, R announced that he wanted to mix the oil and water. I handed him a wooden spoon and he explained that he was making “magic jelly”.

I brought out some of his sensory tub tools and handed him a ladel and a bowl. He continued with his imaginative play and this time delcared that he was making a cake for Daddy. This was a wonderful opportunity for scooping and pouring, something R just loves to do. When I put him to bed that night and asked him what his favourite part of the day had been, he said “Ladelling!” It’s written all over his face….

At one point, the ladel fell deep into the oil and water mixture. I decided to hand him some tongs to retrieve it. We use tongs quite a lot with our Montessori trays. Tonging is great for strengthing the pincer grip and is a great pre-writing and pre-scissor cutting exercise. Although R is pretty skilled with tongs these days, I still imagined there would be no way he would retrieve a heavy metal ladel, slippery with oil, using the tongs. He was up for the challenge.

Having a try….


9 thoughts on “Mixing oil and water – science experiment”

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