TOPIC

Transfer of Heat

RATIONAL

This module is designed to offer guidance to teacher in order to be creative in their teaching and also as an instant lesson plan for a busy teacher. This module is also designed in order to integrate classroom experiences and assimilation of learningwith the students’ life experiences, realities,and expectations.Furthermore, to demonstrate ability to use new knowledge in their world. This module is written and designed for today’s classroom, which incorporates a wide range of intellectual, cultural, physical, and emotional diversities.

MAIN ACTIVITY

Lesson starts with an induction sets. After teacher has done doing the induction set and tell topic of today’s lesson to the students, teacher will plays or uses a flash animation as a teaching aid of the lesson. Students are given with handout of topic’s notes. Then, there are four sets of summative evaluation test for students. The summative tests can be done as a discussion in class,as handouts for students to answer or as group discussion. After the lesson end, there are some suggested activities that can be choose and apply by teacher.

OBJECTIVES

At the end of the lesson, students will be able to:

  1. state that heat flows in threedifferent ways (conduction convection and radiation)
  2. state that heat flows from hot tocold
  3. give examples of heat flow innatural phenomena
  4. to demonstrate dynamicand applied comprehension of thetopic

CONTENT & CORE LEARNING ACTIVITY

(1)Induction Set

Introduction To Vocabulary

Before starting the lesson, teacher writes the word “thermal” on the board. What does this word mean to students? Where have they heard this word, or related words, before?

(Thermal means “relating to or caused by heat.” Some related words include: thermal underwear, thermos, thermometer, thermodynamics, thermonuclear and thermostat.)

Discussion Ideas

The heat that we use on Earth comes from six main sources. Can students name all six sources? What are some ways that we use heat from these sources?

(The six main sources of heat are the sun, fire, friction, nuclear energy, chemical reactions, and heat within the Earth. Heat from the sun warms solar panels that make electrical energy. Heat from fire is used to cook food and produce fuel. Heat from the friction of two sticks rubbing together can help us build a campfire. Lighting a match is an example of a useful chemical reaction that produces heat. Nuclear energy is used to produce electricity for heating our homes.)

Focus

Ask students to think about the various applications of heat. What are some ways that students used heatbefore getting to class today? What would their day have been like without heat? Ask them to keep thesethings in mind as they begin the unit.

Introduction To The Lesson

The presence of heat on the Earth is the basis of all life. Heat is one of the most important elements known to humans. It is used to warm our homes, provide us with light, cook our food, and produce fuel used for transportation and electricity. We can see basic examples of heat all around us. A breeze is created by warm air that is replaced by cool air. A warm stove heats a room as currents circulatethe warm air. Infrared rays from the sun cause our skin to burn.

Then, teacher tells students that today’s lesson is about heat transfer.

(2)Lesson

-Teacher plays a flash animation in the class. Teacher gives explanation based on the flash animation.
TRANSFER OF HEAT

  • Heat transfer throughout our environment all of the time. Wherever you are aware of things that are warm or cold, or a getting warmer or cooler.
  • Dive into swimming pool or walk on the sidewalk barefoot in the summer and you now about heat transfer.
  • In our environment, heat transfer is always from the hotter objects to the colder object.
  • Heat transfers to and through some materials better than others.

Heat can be transferred by the process of:

  • Conduction is the transfer of heat between objects or substances that are in direct contact with each other.
  • This transfer of kinetic energy from the hot to the cold side is called a flow of heat
  • Conduction works well in solids because the atoms are close together. It works poorly in liquids and gases because the atoms are further apart.
  • The better the conductor, the more rapidly heat will transferred.

Hot Cold

The transfer of heat by convection through liquids

The transfer of heat by convection through gases

APPLICATIONS


Natural Convection

Air above warmer ground
rises.


SCIENCE TIP

CONCLUSION

COMPARISON BETWEEN CONDUCTION, CONVECTION AND RADIATION

CONDUCTION / CONVECTION / RADIATION
Medium for the process / Solid / Fluids (liquid or gas) / Solid, liquid or gas
Takes place in vacuum / No / No / Yes
Speed / Slow / Faster than conduction / Very fast
Way heat transfer takes place / Heat is transferred from particles through vibration / Heat is brought by heated particles that move upwards. / Heat moves in the form of waves in a straight line

(3)Student’s Handout

Method of Heat Transfer

  1. What do you mean by the term “heat transfer”?

Heat transfer refers to the process by which heat energy gets from one place to another. Heat place takes place via conduction, convection, or radiation. The energy is transferred from a body with a lower temperature.

Misconceptions of Heat Transfer:

Heat transfer does not include creating heat energy from some other form of energy such as light. Scientists use the term “heat flow”, but heat does not flow like water or any other fluid.

  1. How is heat transferred by conduction?

Conduction occurs primarily in solids. The kinetic energy of the molecule is transferred as the vibrating molecules collide with one another. In this way, energy can be moved from one point to another, even though the molecules themselves are not free to move.

Misconception:

The molecules vibrate, but do not move from one place to place. Collision only between adjacent molecules.

  1. How is heat transferred by convection?

Convection occurs in fluids (liquids and gases). When some portion of a fluid is heated, the faster moving molecules move further apart from one another. Since the colder portion of the fluid is denser, it sinks to the bottom of the container, gradually forcing the hotter, lighter fluid to the top. In convection, the molecules actually move from place to place.

Misconception:

It is incorrect to say that “heat rises”. However, groups of hotter molecules will rise because they are less dense than groups of colder molecules.

  1. How is heat transferred by radiation?

Radiation, unlike conduction and convection, does not involve molecules in the actual transfer process. Hot objects emit energy in the form of electromagnetic waves which radiate through space until they are absorbed by molecules. The waves’ energy is then transformed into kinetic energy in the molecules.

Misconception:

Electromagnetic rays such as light ray do not contain heat. They are a different form of energy which is transformed into heat energy only when the rays strike the molecules.

Commentaryfor teacher:

Many students who recognize heat as a form of energy are confused about the processes by which heat is transferred from one body to another. Their confusion is compounded by terms like “heat flow” and “movement of heat” which are commonly used by physicists to describe transfer of heat energy. Students who view heat as being capable of moving or flowing through a body may never completely abandon the naïve conception that heat is a “fluid”. Thus, they are not apt to fully understand the kinetic-molecular explanation of heat and heat transfer.

This handout confronts students’ misconception about heat transfer processes by contrasting the kinetic-molecular explanations of conduction, convection, and radiation with common naive conception about them.

SUMMATIVE EVALUATION

ACTIVITY 1

Each item below describes an example of thermal energy. For each item, write the word which best explains what is happening: conduction, convection or radiation.

  1. ______Someone places a hand on a metal table and the hand feels cooler.
  1. ______Hot air currents inside a balloon causes the balloon to rise.
  1. ______Energy from the sun travels to the surface of the Earth.
  1. ______Storm clouds form when warm air moves into the atmosphere.
  1. ______Heat from a stove warms a pot of soup.
  1. ______A person turns on a lamp and feels its warmth on his hand.
  1. ______The heat from a space heater rises to the top of a room and is replaced by cooler air.
  1. ______A metal spoon stirring a cup of hot chocolate becomes warm.
  1. ______Water in a swimming pool is warmed by the sun.
  1. ______A person swimming in the ocean begins to feel cooler.

ACTIVITY 2

What heat transfer is taking place in each of the following situation?

Situations / Heat is transferred
From / To / Mechanism (Conduction. Convection or Radiation)
1 / Ice cube in water
2 / Sun shining on the Earth
3 / The Earth at night
4 / Refrigerator door open
5 / Frying an egg
6 / Baking a cake
7 / Touching a hot object
8 / Standing across the room from a hot fireplace

ACTIVITY 3

  1. (a) What happened to the hot fluids?

(b) Give an inference for your answer.

  1. (a) What happen to the cold fluid?

(b) Give an inference for your answer.

3.Name the heat transfer that takes place in fluid.

4.How did the heat transfer process in this activity take place?

When one part of the fluid was heated, the fluids and become . This fluid moved

and the fluid on top

to take the place of the hot fluids.

5.Why were potassium manganate (VII) and smoking paper used?

To enable the ______to be clearly seen.

ACTIVITY 4

Play the PowerPoint interesting quiz game:

The quiz game has 11 questions. After answering each questions, it has interesting responses to student’s answer. The questions have multichoice answer. The questions are:

What type of heat transfer is…(choose between Conduction, Convention, or Radiation)

  1. Warm air rising up
  2. Heat spreading along a metal
  3. Heat reaching you from an electric bar heater
  4. Warm water rising to the top of a hot water tank
  5. A table gets hot underneath a mug of tea
  6. Toast cooking
  7. Smoke rising up a chimney
  8. Heat reaching us from the sun
  9. The burner on a hot air balloon
  10. Touching a hot plate
  11. Sausages cooking under a grill

ACTIVITY 5

TEST YOUR UNDERSTANDING!!

FIGURE 1

1. Figure 1 shows a process of heat transfer through liquids. Which of the following

statements is true?

  1. Hot liquids do not move
  2. Cold liquids that are denser move downwards
  3. Heat is transferred downwards only
  4. Liquids move from cold to hot areas

FIGURE 2

2. Figure 2 shows the formation of sea breeze. Among the points A, B, C and D, at which

point does hot air rise?

Process of heat transfer / Application in daily life
X / Ventilation of buildings
Y / Use in thermometer

TABLE 1

3. Table 1 shows the processes of heat transfer and its applications in daily life. Which of

the following processes of heat transfer are represented by X and Y?

X Y

  1. Radiation Conduction
  2. Conduction Radiation
  3. Convection Radiation
  4. Convection Conduction

3. Which of the following is true about the transmission of heat from the sun to the Earth?

  1. Heat is transmitted by convection
  2. Heat is transmitted by the vibrations of particles
  3. Heat is transmitted at the speed of light
  4. Heat is transmitted upwards only

4. The process of heat transfer takes place from the source of heat to its surroundings

without the need of a medium. Which of the following takes place in this heat transfer?

  1. Land breezes form
  2. Sawdust covering a piece of ice
  3. Heat from a lamp reaching the skin
  4. Ventilation holes on the part of houses.

LEARNING MIND MAP

RESPONSES

ACTIVITY 1

  1. Conduction
  2. Convection
  3. Radiation
  4. Convection
  5. Conduction
  6. Radiation
  7. Convection
  8. Conduction
  9. Radiation
  10. Conduction

ACTIVITY 2

Situations / Heat is transferred
From / To / Mechanism (Conduction. Convection or Radiation)
1 / Ice cube in water / ICE / WATER / CONVECTION
2 / Sun shining on the Earth / SUN / EARTH / RADIATION
3 / The Earth at night / EARTH / SPACE / RADIATION
4 / Refrigerator door open / ROOM / FRIDGE / CONVECTION
5 / Frying an egg / PAN / EGG / CONDUCTION
6 / Baking a cake / OVEN / CAKE / CONVECTION
7 / Touching a hot object / OBJECT / FINGER / CONDUCTION
8 / Standing across the room from a hot fireplace / FIRE- PLACE / PERSON / RADIATION

ACTIVITY 3

  1. (a) Hot fluid moves upwards.

(b) When heated, hot fluid particles expand and become less dense.

  1. (a) Cold fluid moves downward.

(b) cold fluid is denser and flow down to take place the space of hot fluid.

  1. Convection
  2. particles expand, less dense, hot, upward, cold, flow down.
  3. Direction of convection current

ACTIVITY 4

  1. Convection
  2. Conduction
  3. Radiation
  4. Convection
  5. Conduction
  6. Radiation
  7. Convection
  8. Radiation
  9. Convection
  10. Conduction
  11. Radiation

ACTIVITY 5

TEST YOUR UNDERSTANDING!!

  1. B
  2. A
  3. D
  4. C

SUGGESTED ACTIVITIES

Writing (60 minutes)

The scientists listed below worked to help us have a better understanding of heat. Ask students to choose a scientist from the list. Have each student write a one-page summary of their chosen person’s contributions to the understanding of heat. Encourage students to use library books and encyclopedia articles to learn more about their chosen topics.

Nicolas Carnot

Rudolf Clausius

Sir Humphry Davy

Josiah Gibbs

James Joule

Lord Kelvin

Julius R. von Mayer

Benjamin Thompson

Meeting Individual Needs (20 minutes)

Ask students to make sentences using the following words. Encourage them to use a dictionaryif they are uncertain of the meanings. Make sure that their sentences display an understandingof the words as they relate to the program.

  • conduction - transmission of heat by thermal energy from particle to particle
  • convection - transfer of heat that occurs when thermal energy causes currents to form ingases or liquids
  • radiation - process whereby energy in the form of light rays or heat is transmitted fromatoms and molecules as they undergo internal changes

Link to the World (20 minutes)

Heat is a very important element in our daily lives. Ask students to name some important uses of heat. Remind them to include uses that are related to transportation, industry and health care. (We use heat to furnish the energy that makes automobiles, airplanes and trains move. Heat is also used in factories to make many of the products we use, including plastic items, food products and things made from metals and alloys. Heat also generates electricity which we use to warm our homes, produce light and operate appliances. Scientists and medical professionals use heat to kill bacteria and perform chemical experiments. Heat is also used to destroy garbage and human waste materials.)

Hands On(60 minutes)

The following experiment will explain a common example of convection. Students will need a jar of soil, a jar of water and 2 thermometers. Place a thermometer in each of the jars. Set the jars in a patch of sunlight and record the temperature changes. Which material heats more quickly, the water or the soil? (The soil heats more quickly.) Remove the jars from the sunlight, and record the temperature changes again. Which material cools off more quickly, the water or the soil? (The soil cools off more quickly.) Ask students if they have ever felt a breeze at the beach. How can the experiment above explain this phenomenon? (During the day, the ground warms up and becomes warmer than the sea. Warm air over the ground rises as cooler air over the ocean comes in. This causes a breeze. At night, the ground is cooler than the water. Air over the ocean rises while air over the ground blows away. This also causes a breeze.)

In the Newsroom (60 minutes)

Ask students to watch television news broadcast, watching closely for stories related to heat or thermal energy. Have them keep a list of these stories and how they relate to heat. Remind them that many everyday occurrences are linked to thermal energy, including space exploration, medical research, energy conservation, weather occurrences and industry. Encourage students to share their findings in a class discussion. How many unexpected topics were discovered? Did any stories relate to conduction, convection or radiation? Which ones?

Extended Activity (15 minutes)

When something is added to water, the water solution’s freezing point is lowered. This means it will take the solution longer to freeze than ordinary water. Ask students to consider the following substances: ordinary water, water that has just been boiled and saltwater. Which substance will freeze first? Which substances will freeze second and third? Why?

(Water that has just been boiled will freeze first because most of its air has been released. This raises its freezing point. Ordinary water will freeze next, and saltwater will freeze last. The added salt raises its freezing point.)