Mixing oil and water science experiment for kids

Help your children learn about density of liquids with this mixing oil and water science experiment for kids.

Possum (aged 8 years) and Boo (aged 5 years) absolutely love to engage with science experiments and this was certainly a fun one for us.

This simple science activity teaches children about liquid density and highlights how some liquids are heavier or lighter than others.

Recommended age – 5 years +
(Strict and active supervision is required at all times)

Mixing oil and water science experiment for kids

For this science activity, you’ll need to collect the following –

• Baby oil

• Water

• Bowl or jar

• Small cups

• Food coloring

• Dropper

• Spoon

You’ll likely find that all these science requirements are easily sourced.

Fill the small cups with water.

Add 2-3 drops of food coloring to each cup. Stir with spoon.

Fill the larger cup or bowl with baby oil.

Keep in mind, you don’t need your bowl too much with oil. About 1/2 way is fine.

Fill the dropper with the colored water.

Have your child sprinkle the water over the oil and observe.

Ask your child to observe and describe what is happening.

Your child should be able to observe that the droplets of water do not mix with the water.

Why does the oil and water not mix together?

There are two parts to this answer.

Firstly, the molecules in oil are attracted to other molecules in oil.
Same with water, water is attracted to water!

Secondly, oil and water have difference densities. That means they weight different amounts. Oil is much heavier than water so the oil is likely to sit towards the surface of the water.

Your child should notice, adding more and more droplets makes no difference, the water and oil do not combine.

The oil and water would continue to separate, regardless if it were shaken in a tightly secured jar.

Oil and water are not friends. hehehe

Over time teeny tiny droplets of water will look to discolour the oil.

Extend this activity

You might like to extend this activity and challenge your children by adding a few drops of liquid dishwashing detergent.

Does the liquid detergent change your original observations?