UTPA STEM/CBI Courses/Introduction to STEM/Preparation of Soap

Course Title: Introduction to STEM

Lecture Topic: Preparation of Soap

Instructor: Javier Macossay

Institution: University of Texas - Pan American

Backwards Design

Course Objectives

Primary Objectives- By the next class period students will be able to:
- Understand the chemical nature of soap.

Sub Objectives- The objectives will require that students be able to:
- Learn the raw materials for soaps.
- Understand how soaps are synthesized.
- Learn that soaps possess a hydrophilic and hydrophobic region.
- Understand the mechanism of action of soaps (how soaps assemble in micelles).

Difficulties- Students may have difficulty:
- Students may encounter problems understanding the hydrophilic and hydrophobic regions found in soaps.

Real-World Contexts- There are many ways that students can use this material in the real-world, such as:
- Soaps are synthesized from natural sources (animal and/or plant fats) through basic hydrolysis. When soaps are obtained, their molecules contain groups that attract water on one side and groups that repel water on the other side, causing the soap molecules to assemble in particular shapes to “encapsulate” dirt, resulting in the cleaning power of soaps.

Model of Knowledge

Concept Map
- Identification of the raw materials to obtain soaps.
- Understanding the synthesis procedure of soaps.
- Learning the concepts of hydrophilic and hydrophobic.
- Understand the chemical nature of the hydrophilic and hydrophobic groups.
- Understand the formation of micelles by soaps.
- Understand the mechanism of action by which soaps clean.

Content Priorities
- Enduring Understanding
  - Understand how soaps are synthesized and their mechanism of action.
- Important to Do and Know
  - Understand how hydrophilic and hydrophobic groups interact with different chemicals.
- Worth Being Familiar with
  - Become familiar with the raw materials needed to obtain soap.

Assessment of Learning

Formative Assessment
- In Class (groups)
  - Discussion of the chemical nature of soap.
  - Discussion of the mechanism of action of soap.
  - Discussion of the synthesis of soap.
  - Discussion of individual laboratory procedures.
  - Discussion of results and conclusions.

Homework (individual)
- Internet based search of the chemical nature of soap.
- Internet based search of micelle formation.
- Internet based search of the synthesis of soap.
- Analysis of data and interpretation.

Summative Assessment
- Discussion of their conclusions in front of the group.

Legacy Cycle

LOOK AHEAD AND REFLECT BACK

Goals
- Students should be able to understand the interaction between science and technology and real world applications and impact.
Objectives
- Students should learn how soap is synthesized and how and why it assembles in micelles.

THE CHALLENGE

You want to start your company, which will be dedicated to providing cleaning household items, such as soaps, detergents, dish washing detergents and products for cleaning ceramic floors. You have already learned that soaps and detergents can be synthesized form natural oils and fats, but have yet to explore it in the lab. How do you synthesize your company’s soap?

GENERATE IDEAS

Students will research independently the chemical nature of soaps.
Students will research independently the formation of micelles by soaps.
Students will investigate how to synthesize soap.

MULTIPLE PERSPECTIVES

Students will discuss among the individuals in each group their ideas.

RESEARCH & REVISE

Once data is collected, students will discuss their results and draw conclusions.

TEST YOUR METTLE

Students will compare their results against their peers’ observations.

GO PUBLIC

Students will discuss their results among themselves and in front of the class.

LOOK AHEAD AND REFLECT BACK

Based on students’ conclusions and interpretations, the experiment could be expanded to synthesize detergents and compare soaps and detergents.

Test Your Mettle Quiz

True or False? (50 points)

Soaps are the salts of carboxylic acids.
Animal and plant fats contain triglycerides.
The basic hydrolysis of fats can lead to soaps and detergents.
Detergents are salts which might contain Na+ and/or K+.
The scum you observe in your bath tub at home is the reaction between soaps and hard water.
Sufactant is a term employed to describe surface active chemicals, such as soaps and detergents.
Soaps are manufactured using synthetic materials.
Detergents are manufactured using natural materials.
Soaps and detergents present the same behavior in the presence of hard water.
The mechanism of action for cleaning is the same for soaps and detergents.

Multiple choice (50 points)

11. Surfactants can be:

a) Cationic

b) Anionic

c) Neutral

d) None of the above

e) More than one of the above

12. Soaps and detergents contain:

a) A hydrophilic (water loving) moiety (unit)

b) A hydrophobic (oil loving) moiety (unit)

c) More than one of the above

d) None of the above

13. Surfactants act by encapsulating the dirt and/or oil and “removing it and washing it away” from the surface (such as clothes):

a) Yes

b) No

14. Bile acid salts are:

a) Found in the human body

b) Natural surfactants

c) Form micelles to encapsulate and process dietary fats

d) More than one of the above

e) None of the above

15. Commercial detergents, such as Tide contain:

a) Cationic detergents

b) Anionic detergents

c) Neutral detergents

d) Enzymes activated at certain temperatures

e) More than one of the above