Yes, you can mix oil and vinegar together for the perfect salad dressing! It’s called emulsification! Simple science you can set up with ingredients found in your kitchen cupboards. This homemade oil and vinegar dressing is fun chemistry for kids you can eat. Enjoy easy science experiments all year round!
How To Emulsify Oil and Vinegar (aka Make Salad Dressing)
💡 Apply the scientific method by changing one variable. What happens if you conduct the experiment with different types of oil, or vinegar or vary the amount or type of emulsifier?
Supplies:
- Clear glass or jar with lid
- Whisk
- Vinegar
- Oil
- Mustard
Instructions:
STEP 1: Pour about a 1/4 cup of vinegar into your glass or jar. If you use a jar with a lid you don’t need to whisk, just shake!
STEP 2: Now add the oil.
Whisk or shake and then wait a few moments. What happens?
STEP 3: Now repeat this same process, starting with a teaspoon of mustard in your glass.
STEP 4: After adding the vinegar, mix. Then SLOWLY drizzle the oil into the mustard and vinegar mixture WHILE whisking.
STEP 5: Now wait a few moments. Did the same thing happen with this mixture?
What Is Emulsification?
If you have tried our oil and water experiment, or made a homemade lava lamp you would have discovered that oil and water don’t mix. The water molecules are attracted to each other, and the oil molecules stick together. This causes the oil and water to form two separate layers.
💡 See here for a more detailed explanation of why oil and water don’t mix.
Let’s think about salad dressing! How do you keep salad dressing from separating? How do you get oil and vinegar (which contains water) to combine into a smooth, completely mixed combination—at least for a little while. The solution – you need an emulsifier!
Emulsification is a process by which two liquids which can’t dissolve in each other are forced to combine in a liquid mixture (emulsion).
To create a successful emulsion, you need two things: an emulsifier, and force. The force we use below to create our salad dressing is whisking and it breaks apart the oil into tiny particles that can be suspended in the vinegar.
Mustard works as an emulsifier and adds flavor, thanks to mucilage, the mustard seed’s outer coating. The mustard is attracted to both the vinegar and oil molecules. It grabs onto both types of molecules causing oil droplets to be suspended in the water, creating an emulsion.
Other emulsifiers you could use in salad dressing are egg yolk, mayonnaise, tomato paste and honey. Emulsifiers are also used in other foods like sauces, gums, chocolate and ice cream. They hold the ingredients together and give the food a soft and smooth texture.
💡Check out all our chemistry experiments for kids!
Explore More Oil and Water Experiments
Try this simple oil and water experiment with food coloring!
How about a classic homemade lava lamp with oil, water, and alka seltzer tablets!
Making a density tower is another great way to observe how not all liquids weigh the same.
💡 Explore more density experiments [here].
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