Understanding Surface Tension, Surfactants, and Polarity - SCOPES Digital Fabrication
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Lesson Details

Subjects
Science
Age Ranges
8-11, 11-14,
Fab Tools
Classroom Materials,
Author
Nawal Abdul Kareem

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Author

Nawal Abdul Kareem
Nawal Abdul Kareem
Other

Summary

The session aims to understand the work of Agnes Pockels, whose research contributed to our understanding of surface science. It will involve experiments designed to elucidate surface tension, polarity, and the action of surfactants.

What You'll Need

We will need:

1. Water

2. Coin (Make sure it’s round)

3. Glass

4. Liquid Dish Soap

5. Dropper

6. Oil (cooking oil or coconut oil will do)

7. Spoon

8. Bottle

9. Slides for presentation

Lesson Materials

The Instructions

Introduction to Surface Tension

We are going to give a brief introduction to the concept of surface tension

Explain to students that surface tension acts like a skin on the surface of water, holding the water molecules together tightly.

Showing examples of Surface Tension in Nature

We are aiming to help the students recognize examples of surface tension

Discuss how surface tension allows insects to walk on water without sinking and causes water droplets to form round shapes on leaves.

Introducing students to Agnes Pockels, a women in STEM

We are going to introduce students to Agnes Pockels, who is one of the first women in STEM.

She is considered to be the pioneer of surface science.

Introduction to surfactants

Explain that surfactants are substances that can reduce surface tension, making it easier for different substances to mix. 

Understanding the mechanism of surfactants

Show them the working of surfactants using this video:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Introduction to the first experiment of our lesson

The students are going to explore surface tension using common household items

Materials required for the first activity

Explain all the materials required and how we will be using them

Beginning the first experiment

We are going to compare the differences in the amount of drops of water and soap solution a coin can hold.

Ask students to observe how the water droplets are rounded when added to the coin surface

We are going to make soap solution for the second part of our experiment

This solution can be made before the lesson starts.

Make sure that you do not stir the solution vigorously.

Now we are going to add drops of soap solution onto the coin

We are aiming to compare the differences in the amount of drops in each case

Ask students why they think only a few drops of soap solution fit onto the coin

Explaining the results that we observed during the experiment

Discuss how the addition of surfactant reduces the surface tension of water, explaining why the water spreads more easily on the coin.

Understanding real life examples of surfactants

Explain how surfactants are used in firefighting foam to spread and cover fires quickly

Understanding polar and nonpolar molecules

We are going to introduce students to a new concept - Polarity

Teach students about polar and nonpolar molecules, and the differences between them.

Understanding Hybrid Molecules

We are going to explain why surfactants are both polar and nonpolar

Explain that surfactants have both polar and nonpolar ends, allowing them to interact with both types of molecules

Understanding the link between polarity and surface tension

Discuss how the polarity of molecules affects surface tension

Explain the materials required for the second experiment of our lesson

We are going to do another experiment using water, oil, and dish soap

Mixing oil and water

We are going to demonstrate the immiscibility of oil and water through this experiment