2) Good and Bad Conductors

3) Practical Applications of Good conductors

4) Practical Applications of Bad conductors

1) Wool (any color)

2) Adhesive tape

3) 3 straws

4) a pair of scissors

• Pupil states the definition of
  

i) Conduction

ii) Good conductors

iii) Bad conductors

• Pupil lists the examples of good conductors of heat, bad conductors of heat  & insulators
  

Understanding

Pupil explains the process of conduction in his own words on the basis of

i) Kinetic Model

ii) Atomic Model

Applying

• Pupil classifies substances as good conductors of heat, bad conductors of heat  & insulators

• Pupil investigates the conduction of heat that occurs in multiple aspects of daily life
  

Analyzing

• Pupil distinguishes between Good conductors of heat & Bad conductors of heat
  
• Pupil gives scientific reason for non-metals & organic substances being bad conductors of heat
  

Skill

Pupil weaves a wool bracelet with the help of straws & wool

1) Kinetic model

•1 end of solid rod placed in fire → molecules gain heat energy → molecules vibrate → they strike against the neighboring molecules → they also vibrate violently --> these molecules make the molecules next to them vibrate faster & this process continues till the other end of the rod until the vibrations have been transmitted to all the molecules & the entire body has become hot. • In this way heat energy is transferred by conduction from the hotter part to the colder part

2) Atomic model

•Free electrons are not held strong by the nucleus & move within the metal in any direction but do not leave the metal itself •Metal bar heated --> free electrons gain K.E. --> they drift away from the source of heat --> collide against neighboring atoms& give their energy to them •Electrons with less energy move towards source of heat. Thus they carry energy from hot end of solid to cold end without actual visible movement of atoms

Definition of conduction

The mode of transmission of the heat energy from one atom to another atom of a solid, in the direction of lower temperature, without the actual visible movement of the atoms is called conduction

Link for the teacher:

https://play.kahoot.it/#/?quizId=22d4de1b-b687-47f9-bb75-0b9557f96985

link for the students:

https://kahoot.it/#/

eg. metals : silver, copper. aluminium, gold

non-metals : graphite

2) These electrons drift away from the source of heat when the metal is heated, & in doing so carry the heat energy rapidly through the metal

eg : glass, wood, clay, asbestos, rubber, plastics, wax

Q) All liquids except mercury are poor conductors. Explain

Q) All gases without any exception are poor conductors or Air is an insulator of heat- give reason

It is because most of the heat energy can be transferred only through free electrons & not by the actual vibrational movement of its atoms

https://www.udemy.com/igcse-physics-chapter-2-thermal-physics-cambridge-cie/learn/#/lecture/1438420