What makes oil and water mix

Hold them up to a light one at time so you can clearly see what is happening inside the bottle. Did anything change when you shook the bottles?

Do the mixtures look the same in the both? If not, what is different between them? How would you explain the differences that you observe? After 10 minutes have passed look at the contents of the bottles and note the changes. What does the oil and water look like in each bottle? Has the oil mixed with the water, sink to the bottom or rise to the top?

Extra: Add food coloring to the water to get a lava lamp effect Extra: Test other types of soap, such as toothpaste, hand soap and shampoo by mixing them with oil and water.

Build a Cooler. Get smart. Sign up for our email newsletter. Sign Up. Support science journalism. Knowledge awaits. See Subscription Options Already a subscriber? Create Account See Subscription Options. Continue reading with a Scientific American subscription. Subscribe Now You may cancel at any time. Water molecules stick together because the positive end of one water molecule is attracted to the negative end of another.

The structure of an oil molecule is non polar. Its charge is evenly balanced rather than having one positive and one negative end. This means oil molecules are more attracted to other oil molecules than water molecules, and water molecules are more attracted to each other than oil, so the two never mix. The food colouring actually sinks through the oil into the water layer as water is more dense than oil.

This is the basis for a firework in a glass experiment. The two can be forced to mix by adding an emulsifier which creates a mixture of water with oil molecules spread evenly through it or vice versa. Use an eye dropper or plastic pipette to take up a small quantity approx. Place the open end of the eye dropper plastic pipette about 0. Very gently squeeze some of the alcohol into the water and watch carefully what happens.

Record what you see. Draw a picture, take a photograph or write down what you see. Now repeat steps 1—5 but this time use oil not the alcohol. Does the same thing happen? Now repeat steps 1—5 but this time use water, not the alcohol.

Does the same thing happen as happened with the alcohol? Does the same thing happen as happened with the oil? Why do you think there is a difference and what do think is happening? Theory: The chemistry of water mixing with other liquids, like alcohol and oil, is really quite complex. Teacher and Technician Sheet In this practical students will: Make predictions and explain their reasoning. Evaluate their original predictions, using the results of the experiments.

Introduction for teachers: Children are often fascinated by the way substances mix. What do you think will happen if I mix these two liquids together? Will they form layers or will they mix? Will one float on the other?

If so which one will be on top? Curriculum range: Lower primary age but can be used with younger secondary age students to investigate materials: it links with: reporting on findings from enquiries, including oral and written explanations, displays or presentations of results and conclusions; using straightforward scientific evidence to answer questions or to support their findings; compare and group together everyday materials on the basis of their properties; know that some materials will mix, while others will not; build a more systematic understanding of materials by exploring and comparing the properties of a broad range of materials.

Hazard warnings: Care needs to be taken with the alcohol since it is inflammable. Equipment: Per group 2 eye droppers or disposable plastic pipettes 2 beakers cm 3 cm 3 water 10 cm 3 ethanol 10 cm 3 olive oil or any cooking oil 1 measuring cylinder cm 3 Technical notes: Other oils can be used with similar results. Results: Students should be able to observe the results easily.

Download all. Level years years. Use Practical experiments Handout Download. Category Cross-curriculum Compounds and mixtures Properties of matter Asking scientific questions Making predictions Observing and measuring. Related articles.