# Oil and Water Experiment Question

• FlashFry
In summary, the speaker is trying to come up with an experiment to demonstrate a thermodynamic principle in their class. They want to show how ice is less dense than oil and will float, but as it melts into water it will sink through the oil. They are having trouble getting the water droplet to refreeze and rise back to the top of the oil. They have considered using dish soap or dry ice, but there may be issues with both. The recommendation is to put the entire setup in a freezer and record it on video to share with the class.
FlashFry
Hey everybody, I am currently in the process of coming up with a neat experiment for my thermodynamics class and I ran into some trouble. In my thermo class we were discuss phases, and separations and such, and I thought it would be cool to show how ice is less dense than oil and will float, but as it melts into water it will sink through an oil medium.

I am so far successful in recreating the melting part, however, I wanted to add something to this. I wanted to have the water droplet at the bottom of the oil medium refreeze and rise to the top (sort of like a reverse lava lamp).

My design is something like a foot tall glass cylinder, filled with vegetable oil. I let some ice float of on top and slowly melt. At the bottom of the cylinder, I have it sitting in an ice bath with salted water (attempting to get the temp < 0c). Unfortunately it is not working...

After doing some research I learned there can be issues with the water surface tension and sticking to the glass. I've also been having trouble getting the bottom of the glass cold enough to refreeze the droplets. I am hoping to get this to be a continuous process to show off to my class. After some brainstorming I was thinking of including another medium between the oil and glass to allow the water to sit without sticking, I might using dish soap... As for the freezing, I was thinking dry ice.

Any help or other ideas for showing off these cool thermodynamic principle would be greatly appreciated, thank you for your time!

Dish soap is soluble in water so I don't think it would work. Dry ice *might* work, you have to tie it to a rock and drop it in, but the bubbles could give you trouble.

My recommendation is to put the entire thing in a freezer and capture it on video, then bring a flash drive to class with the file and play it over a projector if you have one available.

## 1. What is the purpose of the oil and water experiment?

The purpose of the oil and water experiment is to demonstrate the properties of oil and water, specifically their inability to mix due to their different densities and polarities.

## 2. How do you perform the oil and water experiment?

To perform the oil and water experiment, fill a clear container with water and add a few drops of food coloring to make the water more visible. Then, slowly pour oil on top of the water. Notice how the oil sits on top of the water and does not mix. You can also try adding a small amount of dish soap to see how it breaks up the oil.

## 3. Why do oil and water not mix?

Oil and water do not mix because they have different densities and polarities. Oil is less dense than water and has nonpolar molecules, while water is more dense and has polar molecules. This difference causes them to repel each other and remain separated.

## 4. What other substances can be used in the oil and water experiment?

Other substances that can be used in the oil and water experiment include alcohol, vinegar, and other oils. These substances also have different densities and polarities, allowing for further exploration of their properties and interactions.

## 5. What can we learn from the oil and water experiment?

The oil and water experiment teaches us about the properties of different substances and how they interact with each other. It also demonstrates the concept of density and polarity and how they affect the behavior of liquids. Additionally, this experiment can be used to explain real-life situations, such as the separation of oil and water in an oil spill.

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