Class: Senior Secondary School 1 (SS1, SS 1, SSS1, SSS 1)
Term: 1st Term
Week: 12
Age: 15 years
Duration: 45 minutes
Subject: Clothing and Textiles
Curriculum Theme: Clothing and Textiles
Previous Lesson: Manufacturing and Properties of Fibre: Artificial Fibres.
Topic: TEST FOR FABRIC IDENTIFICATION
Subject Matter: fabric identification by handling, fabric identification by burning and flame test, chemical test for fabric identification, microscopic test for fabric identification

Specific Objectives

By the end of the lesson, pupils should be able to:

Cognitive Domain:

Explain the different methods of fabric identification.
State the observations for various fabrics during burning and chemical tests.
Identify different fabric types based on test results.

Affective Domain:

Appreciate the importance of identifying fabric types for proper care and use.
Show interest in carrying out practical tests for fabric identification.

Psychomotor Domain:

Carry out basic fabric identification tests by handling and burning.
Record observations accurately during practical fabric tests.

Collaborate with peers during practical fabric identification activities.
Share findings and observations with the class.

Reference Materials

The following resources were used in planning this lesson:

9 Years Basic Education Curriculum for Home Economics.
State Unified Scheme of Work for Senior Secondary Schools.
Clothing and Textiles for Senior Secondary Schools, Book 1.

Instructional Materials

The teacher will teach this lesson with the aid of:

Various fabric samples (e.g., cotton, wool, silk, rayon, polyester, nylon).
Matches or a lighter.
Small ceramic dish or heat-resistant surface.
Forceps or tongs.
Dilute nitric acid, dilute hydrochloric acid, sodium hypochlorite solution (bleach), acetone.
Droppers.
Microscope and slides (optional).

Rationale for the Lesson

This lesson helps pupils understand how to differentiate between various fabric types. This knowledge is important for making informed decisions about garment care, purchasing, and suitability for different purposes in their daily lives.

Prerequisite/Previous Knowledge

Pupils should have a basic understanding of different types of textile fibres (natural and synthetic) and their general characteristics.

Lesson Content/Board Summary

TEST FOR FABRIC IDENTIFICATION

Fabric Identification by Handling

Fabric identification by handling involves using touch, sight, and sound to determine the general characteristics of a fabric. This method is quick but requires experience.

The following are observations during handling:

Cotton: Feels soft, cool, and somewhat crisp. Wrinkles easily.
Linen: Feels cool, smooth, and crisp. Wrinkles easily and has a characteristic ‘flaxen’ feel.
Wool: Feels warm, soft, springy, and sometimes slightly scratchy. Does not wrinkle easily.
Silk: Feels smooth, soft, lustrous, and drapes well.
Rayon: Feels soft, smooth, and drapes well, similar to silk but can feel cooler.
Polyester: Feels smooth, often slick, cool, and strong. Resists wrinkling.
Nylon: Feels smooth, very strong, lightweight, and often slick.

Fabric Identification by Burning and Flame Test

The burning test involves observing how a fabric sample reacts to a flame, how it burns, the smell of the smoke, and the appearance of the ash. This test is effective for distinguishing between major fibre groups.

The following are observations during burning and flame test:

Cotton/Linen (Cellulosic Fibres):
- Flame: Burns quickly with a yellow flame.
- Smell: Smells like burning paper or leaves.
- Ash: Produces a fine, grey, feathery ash.
Wool/Silk (Protein Fibres):
- Flame: Burns slowly, often sputters, curls away from the flame, and self-extinguishes when removed.
- Smell: Smells like burning hair or feathers.
- Ash: Forms a brittle, black, crushable bead.
Rayon (Regenerated Cellulosic):
- Flame: Burns quickly with a yellow flame, similar to cotton.
- Smell: Smells like burning paper.
- Ash: Forms a fine, grey ash.
Polyester (Synthetic Fibres):
- Flame: Melts and drips away from the flame, burns slowly with a dark, smoky flame.
- Smell: Smells slightly sweet or chemical.
- Ash: Forms a hard, black, non-crushable bead.
Nylon (Synthetic Fibres):
- Flame: Melts, drips, and shrinks away from the flame, burns slowly.
- Smell: Smells like burning plastic or celery.
- Ash: Forms a hard, round, grey or brown bead.

Chemical Test for Fabric Identification

Chemical tests use specific reagents to dissolve or react with different fibre types, providing further identification. These tests should be performed carefully in a well-ventilated area.

The following are observations during chemical tests:

Dilute Hydrochloric Acid (HCl):
- Dissolves silk.
- Has little effect on wool, cotton, linen, rayon, polyester, nylon.
Dilute Nitric Acid (HNO₃):
- Turns silk yellow.
- Turns wool yellow.
- Has little effect on cotton, linen, rayon, polyester, nylon.
Sodium Hypochlorite (Bleach):
- Dissolves wool and silk (protein fibres).
- Has little effect on cotton, linen, rayon, polyester, nylon.
Acetone:
- Dissolves acetate.
- Has little effect on other common fibres.

Microscopic Test for Fabric Identification

Microscopic examination reveals the unique structural features of different fibres, such as their shape, surface characteristics, and presence of scales or convolutions.

The following are observations under a microscope:

Cotton: Flat, ribbon-like with convolutions (twists).
Linen: Straight, rod-like with nodes (bamboo-like joints).
Wool: Scaly surface, crimped (wavy).
Silk: Smooth, lustrous, triangular cross-section.
Rayon: Smooth, uniform, often with striations (lines) along the length.
Polyester/Nylon: Smooth, uniform, rod-like, often perfectly circular in cross-section.

Teaching Methods/Instructional Techniques

Discussion, Lecture, Demonstration, Question and Answer, Visual Aids, Practical Activity

Instructional Procedures

Step 1: Introduction

Time: 5 minutes
Teaching Skill: Set Induction/Questioning
Teacher’s Activity: The teacher greets the pupils and asks them to recall different types of fabrics they know and what makes them different (e.g., feel, appearance). The teacher introduces the topic: “Test for Fabric Identification.”
Pupils’ Activity: Pupils respond to the teacher’s questions, mentioning fabrics like cotton, wool, silk, and suggesting differences in how they feel or look.
Learning Point: Pupils are prepared for the lesson and connect previous knowledge to the new topic.

Step 2: Explanation of Fabric Identification Methods

Time: 7 minutes
Teaching Skill: Explanation/Lecture
Teacher’s Activity: The teacher explains that fabrics can be identified through various methods, including handling, burning, chemical tests, and microscopic examination. The teacher briefly describes each method.
Pupils’ Activity: Pupils listen attentively and take notes.
Learning Point: Pupils understand the different approaches to identifying fabrics.

Step 3: Demonstration of Fabric Identification by Handling

Time: 5 minutes
Teaching Skill: Demonstration/Observation
Teacher’s Activity: The teacher displays different fabric samples and demonstrates how to identify them by handling, describing the feel, drape, and appearance of each (e.g., cotton feels cool and crisp, wool feels warm and springy).
Pupils’ Activity: Pupils observe the teacher’s demonstration and handle the fabric samples provided, noting the differences.
Learning Point: Pupils learn to identify fabrics by touch and sight.

Step 4: Demonstration of Burning and Flame Test

Time: 10 minutes
Teaching Skill: Demonstration/Safety Instruction
Teacher’s Activity: The teacher demonstrates the burning test using small samples of different fabrics (e.g., cotton, wool, polyester). The teacher emphasizes safety precautions and guides pupils to observe: how the fabric burns, the smell of the smoke, and the appearance of the ash. The teacher explains the observations for each fibre type.
Pupils’ Activity: Pupils observe the burning test carefully, noting the characteristics of the flame, smell, and ash for each fabric type. They ask questions for clarification.
Learning Point: Pupils understand how to perform and interpret the burning test for fabric identification.

Step 5: Introduction to Chemical and Microscopic Tests

Time: 8 minutes
Teaching Skill: Explanation/Discussion
Teacher’s Activity: The teacher introduces chemical tests, explaining that specific chemicals react differently with various fibres (e.g., bleach dissolves protein fibres). The teacher also briefly explains the microscopic test, mentioning that fibres have unique structures visible under a microscope. The teacher discusses the typical observations for various fibres under these tests.
Pupils’ Activity: Pupils listen, ask questions, and discuss the principles behind chemical and microscopic identification.
Learning Point: Pupils gain knowledge about chemical and microscopic methods of fabric identification and their expected results.

Step 6: Practical Activity (Group Work)

Time: 5 minutes
Teaching Skill: Facilitation/Practical Application
Teacher’s Activity: The teacher divides pupils into small groups and provides them with unlabelled fabric samples. The teacher instructs them to use the handling and burning tests (under strict supervision) to identify the fabrics, recording their observations.
Pupils’ Activity: Pupils work in groups to perform the handling and burning tests on the provided fabric samples, discussing their observations and attempting to identify the fabrics.
Learning Point: Pupils apply the learned techniques to identify fabrics practically.

Step 7: Evaluation/Review

Time: 5 minutes

Teaching Skill: Questioning/Assessment

Teacher’s Activity: The teacher evaluates the learning by asking the following questions:

Mention three methods of fabric identification.
Describe the burning characteristics of cotton and wool.
What is the smell of burning silk?
Which chemical can dissolve wool and silk?

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 8: Conclusion

Time: 2 minutes
Teaching Skill: Summarisation
Teacher’s Activity: The teacher summarizes the key learning points of the lesson, reiterating the importance of knowing how to identify different fabric types for proper care and use. The teacher assigns homework.
Pupils’ Activity: Pupils listen to the summary and copy down the homework.
Learning Point: Pupils consolidate their understanding of fabric identification methods.

Lesson Keywords

Fabric Identification – The process of determining the type of fibre or material a fabric is made from.
Handling Test – Identifying fabric by touch, sight, and feel.
Burning Test – Identifying fabric by observing its reaction to flame, smell, and ash.
Chemical Test – Identifying fabric by observing its reaction to specific chemical reagents.
Microscopic Test – Identifying fabric by examining its unique structural features under a microscope.
Cellulosic Fibres – Fibres derived from plant sources, such as cotton and linen.
Protein Fibres – Fibres derived from animal sources, such as wool and silk.
Synthetic Fibres – Man-made fibres from chemical compounds, such as polyester and nylon.

Differentiation

For pupils who grasp concepts quickly, the teacher can encourage them to research more advanced chemical tests or different types of synthetic fibres. For pupils needing more support, the teacher can provide simplified charts of burning characteristics and offer more guided practice during the practical activity.

Note for teachers using this lesson plan

Ensure all safety precautions are strictly followed during the burning and chemical tests. Provide adequate ventilation and supervise pupils closely. Prepare fabric samples and reagents in advance. Encourage pupils to record detailed observations during practical activities to enhance their learning.