This is a bonus episode to SS #28: Oil and Water Story.  As promised, in this episode, Deepa shares her observations from the fun activity.

Narrator: Deepa



Hey there, this is Aasif here and this is a bonus episode. This episode is the answer to the previous episode, which is the story of oil and water, an experiment suggested by Deepa. So here is the solution for that.

00:40  Hello, Mango Radio listeners. This is Deepa again. I told you about this water and oil experiment,  right? I hope you have done the experiment and made your own observations. I’m here to share my observations. So I did this experiment too. I added first water and oil in a bottle and shook it well, and I kept it on the desk to see, to observe what happened to it. And I saw, actually, water and oil did not mix; there were two layers I could make out. One was the oil layer and one was a layer of water. So like I told you, as I suggested, I also added dishwashing liquid into the bottle and I shook it again. This time I did not see two separate layers. What I saw was a cloudy mixture. I could not make out oil from water in this mixture, and how does this happen? What does soap do to oil and water? I read up on it and this is what I found out. I thought I would share it with you guys.

02:14  Dishwash liquid that you use is a kind of soap. Yes? Normally oil and water do not mix, so they separate into two different layers. Here is what soap does. Soap first breaks up the oil into smaller drops, so small that you are unable to see it. It’s broken up into such small droplets which can be pulled by water. It works because soap is made up of molecules with two different ends. One end of the soap molecules love water – they are hydrophilic. Philia means love, and Hydro is water. So they love water. The other end of the soap molecules hate water – they are hydrophobic. Phobia is fear and Hydro means water. They have a fear of water so they don’t get attracted to the water.

03:21  So, the hydrophobic ends of the soap all attach to the oil and the hydrophilic ends of the soap stick out into the water. This makes a drop of oil to form on the water. A very very very minor drop. These drops of oil are suspended in the water. This is how the soap cleans your hand. It causes drops of oil and dirt to be pulled off from your hands and get attracted to the water and get suspended in the water. Then when you wash away the water, these drops are washed away with it. So that is why oil can be wiped away with soap. I hope you guys understood this concept. Bye!

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Music by Karthikeyan KC