Heat

ಕನ್ನಡದಲ್ಲಿ ನೋಡಿ

Concept Map

Error: Mind Map file Heat.mm not found

Additional Information

simple experiments on Effect of Heat,click here

Useful Websites

Wikipedia for Heat
Wikipedia for Thermal energy
Heat
Thermodynamics
Kinetic Energy

Textbook

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TamilNadu Textbook

• Class - IX Heat and Gas Laws

Teaching Outlines: HEAT

• Effects of heat : Expansion of solid, liquid and gases.

• Expansion of solids : Linear,superficial and volume expansion, it's practical examples.

• Bimetallic strip and it's applications.

• Expansion of Liquids : Anomalous expansion of water and its effect.

• Expansion of gases.

• Heat capacity : Meaning, some examples of high and low heat capacity.

• Specific heat : Meaning, consequences of high specific heat capacity of water.

• Latent heat : Latent heat of fusion and Latent heat of vapourization.

• Numericals.

Concept-1: Nature and Effects of Heat

• Nature of Heat

• Effects of heat : Expansion of solid, liquid and gases.

• Expansion of solids : Linear,superficial and volume expansion, it's practical examples.

• Bimetallic strip and it's applications.

• Expansion of Liquids : Anomalous expansion of water and its effect.

• Expansion of gases.

Learning objectives

• Heat is a form of Energy.Sun is a primary source of Heat and Light.Transfer of heat takes place from hotter object to cold object till both reach the same temperature.It depends upon the speed of the particles,the number of particles and the size or mass and the type of particles in an object.

• Objects such as solid, liquid and gases generally increase in their size when heated. This effect of heat is called Expansion of objects/Thermal expansion.Other than this increase in temperature and Change of physical state are also the Effect of Heat.

1. Explains the Nature of Heat.
2. Identifies the effects of heat in everyday life.
3. Explains the thermal expansion of solids,liquids and gases with examples.
4. Mentions the applications of the thermal expansion of solids,liquids and gases.
5. Describes the relation between the co-efficient of linear,superficial and volume expansion.
6. Mentions the application of bimetallic strip in thermostat.
7. Explains the anomalous expansion of water and mentions its consequences.

Notes for teachers

These are short notes that the teacher wants to share about the concept, any locally relevant information, specific instructions on what kind of methodology used and common misconceptions/mistakes.

Activity #1 Thought Experiment to introduce heat

• Estimated Time
  

40 minutes

• Materials/ Resources needed
  

Black Board, Pencil, Paper

• Prerequisites/Instructions, if any
  

Understanding of work and energy

• Multimedia resources
  
• Website interactives/ links/ simulations
  
• Process (How to do the activity)
  

1. Let us do a thought experiment. Let us think about a small activity. We will do it as a thought experiment! Do you know what a thought experiment is? It is something we conduct in our mind. Where we follow all the rules of science. Many scientists have conducted thought experiments to understand many difficult phenomena.
2. Let us say we have 4 bunsen burners. We will put three beakers – one of oil, water and milk on each of the burners and one metal spoon on the fourth burner. The quantity of oil, water and milk should be the same. We will keep the burner on for 4 minutes. Now we will try to answer some questions.

• Developmental Questions (What discussion questions)
  

1. At the end of 4 minutes, we will measure the temperature of the oil, water and milk. Can you even touch the spoon at the end of 4 minutes? Which do you think will feel hottest?
2. What has happened to all these 4 substances? All 4 substances have become hot, some will be more hot - some less hot.
3. When we put something on a fire, it become hot. It becomes hot by absorbing the heat from the fire. How hot it becomes depends on the the material and the mass of the object. Every material absorbs heat differently. This depends on how the molecules are arranged in the object.

• Evaluation (Questions for assessment of the child)
  

1. Can you explain how heat is used in cooking?
2. How does heat from the sun work?

• Question Corner

Activity No # 2 Heat is energy

Click to Comment

• Estimated Time
  

40 minutes

• Materials/ Resources needed
  

DVD Player, Computer

• Prerequisites/Instructions, if any
  

Introduction to energy

• Multimedia resources
  

• Website interactives/ links/ simulations
  
• Process (How to do the activity)
  

After showing the video discuss the following.

• Developmental Questions (What discussion questions)
  

1. How does the water become more hot in the first video?
2. We have seen that energy means ability to do work. When we say energy we usually think of movement, potential energy, kinetic energy, light, etc.
3. What about heat? Heat is a form of energy. When we rub our hands together, drag an object over another or even sharpen a tool, we will notice that heat is generated. Our hands will get warm and the tools will also become very hot.
4. Why does this happen? Molecules inside an object are always moving and when their movement is increased, their energy is increased. And this is what is felt as heat. We can see that heat is a form of energy.

• Evaluation (Questions for assessment of the child)

• Question Corner

1. We saw that mechanical energy (rubbing, jumping) can produce heat. Can heat also move things? How does a steam engine work?

Concept-2: Heat capacity

• Heat capacity : Meaning, some examples of high and low heat capacity.

• Specific heat : Meaning, consequences of high specific heat capacity of water.

• Latent heat : Latent heat of fusion and Latent heat of vapourization.

• Numericals.

Learning objectives

• The capacity to hold Heat is different for different substances.This capacity of a substance to hold heat is expressed by a quantity called Thermal capacity/Heat capacity. Due to this property, either adding or removing heat from a substance can change its physical state.

1. Defines heat capacity and specific heat.
2. Gives examples for high and low heat capacity.
3. Mentions the consequences of high specific heat capacity of water.
4. Illustrates the latent heat of fusion and latent heat of vaporization.
5. solves the Numericals using the formulae.

Notes for teachers

These are short notes that the teacher wants to share about the concept, any locally relevant information, specific instructions on what kind of methodology used and common misconceptions/mistakes.

When we touch something we often say it is hot or cold. Obviously we are referring to some property that feels different with respect to our own body and we refer to this as energy. We have also noticed that we feel hotness when we are near fire or a light or from the sun. The characteristic of matter we are referring to is the energy that is contained and transmitted; Every object possesses internal thermal energy contained in an object and this depends on the amount of the substance.

The transfer of this energy from one object to another is felt and described as heat. Heat thus refers to one of the forms in which the energy in an object can be transferred to its surroundings.

Yet another observation we can make with respect to heat is how hot or how cold an object is. The degree of hotness or coldness of an object is what we use to compare the heat energy contained in an object with respect to its surroundings. This degree of hotness or coldness is what we measure as temperature. How hot or cold something will determine how much energy it will give out to or receive from the environment.

Temperature of an object determines how much energy - heat - it will give out or receive.

Activity #1 Explaining the difference between heat and temperature

*Estimated Time
*Materials/ Resources needed
Downloaded video, DVD player/ Computer and projector
*Prerequisites/Instructions, if any
*Multimedia resources
This lively video explains the difference between heat and temperature. How are the heat and temperature related? Comparing heat energy and degree of temperature.

One more video on the same topic of Heat and temperature.
*Website interactives/ Links/ Simulations
Interactive simulation on temperature. NSTA-Learning-Object

• Process (How to do the activity)
  

Show the video and discuss the following questions.

• Developmental Questions (What discussion questions)
  

1. How would you describe temperature?
2. Why does the cup of water not heat the pool the same amount as the bucket of water?
3. If I heat an iron rod as well as a pot of water on a wood stove for 10 minutes which would have the higher temperature, why?

• Evaluation (Questions for assessment of the child)
  
• Question Corner

Activity #2 Explaining the Heat capacity of a substance

• Estimated time
  

20 minutes

• Materials required
  

Cylindrical tube of Aluminium,Iron and Copper,Boiling water and Wax plank.

• Process
  

1. Take cylinders made of Aluminium,iron and copper having same mass and area of cross section.
2. Place them in boiling water.
3. After some time, the temperature of these cylinders will be equal to that of the boiling water.
4. Remove these cylinders at the same temperature from boiling water and place them on plank made of wax.
   

• Developmental questions
  

1. Which of these cylinders is found to penetrate deepest into the wax?
2. Which of them has penetrated the least? Why?

Fun corner

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