Oil Bubbles in Water Science Experiment

Oil bubbles? With this easy science experiment, kids can explore density and a little bit of chemistry as they make oil bubbles with just a few common kitchen items.

This experiment includes a demonstration video, printable materials list and instructions, experiment variations to try, and a simple explanation of how the experiment works.

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Supplies Needed

• Large Empty Clear Jar
• 2 Cups of Water
• 1 Cup Vegetable Oil
• 4 Tablespoons of Salt

Oil Bubbles Science Experiment Instructions

Step 1 – Begin by fulling a large jar about halfway full of water.

Step 2 – Next, add a cup of vegetable oil to the jar. Wait 30 seconds for the oil to completely separates from the water. Take a moment to make some observations. What do you notice about the oil and the water? What do you think will happen if you add salt to the jar? Write down your hypothesis (prediction) and then follow the steps below.

Step 3 – Add a heaping tablespoon of salt to the jar. 

Step 4 – Observe what happens next. Do you see the bubbles form at the bottom and float back to the top? Do you know why this happens? Find out the answer in the how does this experiment work section below.

Video Tutorial

Create Oil Bubbles in Water Science Experiment Step by Step Instructional Video

How Does the Science Experiment Work

Oil and water do not mix. When you pour them into the jar, the oil floats on top of the water because oil is less dense (density) than water. This means oil is lighter for the same amount of space.

When you add salt to the jar, the salt sinks through the oil and into the water. As the salt sinks, it picks up some of the oil and carries it down with it.

Once the salt reaches the water, it begins to dissolve. As the salt dissolves, the oil is released and rises back to the top because oil is less dense than water. As the oil rises, it forms small bubbles that move through the water.

The oil eventually reaches the top and forms a layer above the water again. This process can be repeated by adding more salt, creating a fun bubbling effect!

Other Ideas to Try

Try this experiment again using two jars. In one jar use warm water and the other jar use cold water. How do these two different temperature waters affect the rate at which salt dissolves (which jar do the oil bubbles rise the fastest)?

Try the experiment again, but instead of using salt, use an Alka Seltzer tablet. The fizz of the Alka Seltzer tablet will produce oil bubbles the same as the salt, but because this is a chemical reaction happening, it will be faster and more bubbles!

I hope you enjoyed the experiment. Here are some printable instructions:

Oil Bubbles in Water Science Experiment

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Materials

• Large Empty Clear Jar
• 2 Cups of Water
• 1 Cup Vegetable Oil
• 4 Tablespoons of Salt

Instructions

1. Begin by fulling a large jar about halfway full of water
2. Next, add a cup of vegetable oil to the jar. Wait 30 seconds for the oil to completely separates from the water.
3. Add a heaping tablespoon of salt to the jar.
4. Watch the Bubbles form at the bottom and float back to the top.