# Thomson’s atomic model lesson plan

Contents in the Article

Complete Lesson Plan of Thomson’s atomic model Class IX

This article contains complete lesson plan of Thomson’s atomic model of Class IX NCERT following CBSE board including introductory questions.

#### GENERAL AIMS

1. To develop interest of students in physical science.
2. To develop an inquiry spirit in the students.
3. To help students to see the physical science in relation to the rest of the culture.
4. To develop interest in questioning.
5. To develop critical thinking and scientific attitude.
6. To develop supervisory ability in students.
7. To develop problem solving skills in students.
8. To make the students aware about inventions in the field of physical science and acquaint them with the knowledge of different streams of physical science.

#### SPECIFIC OBJECTIVES

1. Students will be able to recall atoms.
2. Students will be able to describe the pudding model of atom.
3. Students will be able to prepare model of Thomson’s atomic model.

#### TEACHING AIDS

Chart, Roller board, pointer and other useful classroom equipments.

#### INTRODUCTORY QUESTIONS

 PUPIL-TEACHER ACTIVITY STUDENT’s RESPONSE Q1. Name some large sized fruit? papaya, watermelon Q2. How does structure of water-melon appears from inside? Seeds are embedded in red-colored sphere Q3. Which model does this structure resemble? Thomson’s atomic model

#### STATEMENT OF AIM

So, today we are going to study the topic ‘Thomson’s atomic model’.

#### PRESENTATION

##### Teaching point 1: Pudding model of atom by Thomson
• J. J. Thomson proposed the model of an atom to be similar to Christmas pudding.
• This model tried to explain the inner structure of the atom theoretically.
• This model is also called watermelon model due to its resemblance to watermelon.
• According to this model, the positive charge in the atom is spread all over like the red edible part of watermelon, while the electrons are embedded in the positively charged sphere, like the seeds in the watermelon.
##### Teaching point 2: Postulates of Thomson’s atomic model

Thomson proposed two postulates for his atomic model:

• An atom consists of a positively charged sphere and the electrons are embedded in it.
• The negative and positive charges are equal in magnitude. So, atom as a whole is electrically neutral.
##### Teaching point 3: Limitations of Thomson’s atomic model

• It failed to explain the stability of an atom because his model failed to explain how a positive charge holds the negatively charged electrons in an atom. Therefore, this theory failed to account for the position of the nucleus in an atom.
• No experimental evidence in its support.

#### BLACKBOARD SUMMARY

• J. J. Thomson proposed pudding model of an atom.
• This model is also known as watermelon model.
• According to this mode, positive charge is spread all over, in an atom and electrons are embedded in it.
• He also said, negative and positive charges are equal in magnitude.
• This model failed to explain the stability of atom.

#### CLASSROOM SUPERVISION

Pupil-teacher will supervise the students work and solve the problems of the students.

#### EVALUATION QUESTIONS

Q1. Who proposed pudding model of atom?

Q2. In Thomson’s model, magnitude of negative & positive charge was ________.

Q3. Atom as a whole was considered electrically neutral. (True/False)

Q4. Positive and negative charges were unequal in magnitude. (True/False)

Q5. Thomson’s model failed to explain _____________ of atom.

#### HOME-WORK

Q. Why Thomson’s model of atom was called watermelon model?

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