Science 4 Quarter 3 Module 3: Light, Sound and Heat Travel

Science Quarter 3 – Module 3: Light, Sound and Heat Travel

CO_Q3_Science 4_ Module 3

Copyright and Development Team

Science – Grade 4 Alternative Delivery Mode Quarter 3 – Module 3 “Light, Sound and Heat Travel” First Edition, 2020

Republic Act 8293, section 176 states that: No copyright shall subsist in any work of the Government of the Philippines. However, prior approval of the government agency or office wherein the work is created shall be necessary for exploitation of such work for profit. Such agency or office may, among other things, impose as a condition the payment of royalties.

Borrowed materials (i.e., songs, stories, poems, pictures, photos, brand names, trademarks, etc.) included in this book are owned by their respective copyright holders. Every effort has been exerted to locate and seek permission to use these materials from their respective copyright owners. The publisher and authors do not represent nor claim ownership over them.

Published by the Department of Education Secretary: Leonor Magtolis Briones Undersecretary: Diosdado M. San Antonio

Development Team of the Module

Author: Rechilda B. Torrero

Editors: Noel V. Ibis Christian M. Espiritu

Reviewer: Chozara P. Duroy

Illustrators: Jotham D. Balonzo Kristal Grace C. Ilao

Layout Artist: Jogene Alilly C. San Juan, Jecson L. Oafallas

Management Team: Gilbert T. Sadsad, Francisco B. Bulalacao Jr., Grace U. Rabelas, Ma. Leilani R. Lorico, Emma T. Soriano, B. Dumail

Printed in the Philippines by _____

Department of Education – Region V

Office Address: Regional Center Site, Rawis, Legazpi City 4500 Telefax: 0917 178 1288 E-mail Address: region5@deped.gov.ph

4

Science

Quarter 3 – Module 3: Light, Sound and Heat Travel

Introductory Message

This Self-Learning Module (SLM) is prepared so that you, our dear learners, can continue your studies and learn while at home. Activities, questions, directions, exercises, and discussions are carefully stated for you to understand each lesson.

Each SLM is composed of different parts. Each part shall guide you step-by-step as you discover and understand the lesson prepared for you.

Pre-tests are provided to measure your prior knowledge on lessons in each SLM. This will tell you if you need to proceed on completing this module or if you need to ask your facilitator or your teacher’s assistance for better understanding of the lesson. At the end of each module, you need to answer the post-test to self-check your learning. Answer keys are provided for each activity and test. We trust that you will be honest in using these.

In addition to the material in the main text, Notes to the Teacher are also provided to our facilitators and parents for strategies and reminders on how they can best help you on your home-based learning.

Please use this module with care. Do not put unnecessary marks on any part of this SLM. Use a separate sheet of paper in answering the exercises and tests. And read the instructions carefully before performing each task.

If you have any questions in using this SLM or any difficulty in answering the tasks in this module, do not hesitate to consult your teacher or facilitator.

Thank you.

What I Need to Know

Light, sound and heat are essential part of our lives. Light allows us to see objects, shapes, and colors. Sound is the main form of communications for us humans. Without sound, we would not hear and therefore would not be able to speak. Sounds are also used by animals for communication. On the other hand, heat is needed for our activities like cooking, drying the washed clothes, and warming our bodies during cold weather.

In this module, you will be informed of how light, sound and heat travel in different media. You will be provided with activities which will help you develop the concepts you have to learn.

The lesson focuses on:

• Lesson 1- How Light Travels (S4FE-IIIf-g-4)
• Lesson 2- How Sound Travels (S4FE-IIIf-g-4)
• Lesson 3- How Heat Travels (S4FE-IIIf-g-4)

After going through this module, you are expected to be able to:

1. describe how light travels;
2. describe how sound travels in solid, liquid and gas materials; and
3. describe how heat travels in solid materials, through liquid materials and air.

What I Know

A. Directions: Write FACT if the statement is true and BLUFF if it is false in your science notebook.

1. Sound travels in waves.
2. Light needs air to travel.
3. Sound travels fastest in a vacuum.
4. Sound travels faster in liquid than gas.
5. Sound travels together with the medium.
6. Sound can travel through solids, liquids and gas.
7. Light travels in a straight line until it hits something.
8. Light is a form of energy that we can see things with our eyes.
9. When light hits a material, it begins to travel in a curve line.
10. Light travels at a speed of 300,000 kilometers per second through a vacuum.

B. Directions: Study the illustrations below on how heat travels. Identify whether heat travels through conduction, convection, or radiation. Write the correct answer in your science notebook.

[illustration: 1 – a pot of steaming liquid with a stirring stick]

[illustration: 2 – the sun shining over trees and plants on the ground]

[illustration: 3 – a kettle on a table with a hand holding its handle over steam]

[illustration: 4 – a hand stirring a pot of steaming food over a fire]

[illustration: 5 – a boy sitting near a campfire, warming his hands]

Well done! Please check your answers against the Answer Key found at the end of the module. If you got 12 to 15 correct answers, that means you’re on the right track. If not, it’s okay, you will have more activities that can help you learn more about this.

Close your eyes for a minute, and then open them afterwards. What did you see when you closed your eyes? How about when you opened them? Have you wondered how we are able to see all the things around us? It is all because of light. The world will be so dark without light. You can only see the beauty of our surroundings because of light. Light is very important for us to live. This module will try to uncover the concepts on how light travels and its properties.

Lesson 1 “How Light Travels”

What’s In

A. Directions: Identify the following parts of magnetic field lines. Write your answer in your science notebook.

[chart: diagram; magnetic field lines around a bar magnet, with three blank labeled boxes numbered 1, 2 and 3]

B. Directions: Determine whether the following pairs of magnets will repel or attract each other. Write your answer in your science notebook.

[illustration: six numbered pairs of magnets (1 to 6), some bar magnets and some horseshoe magnets, with N and S poles labeled]

Great! You must have gotten all the correct answers. Now, it’s time to discover more about the new lesson.

What’s New

Note to Parent/Learning Facilitator: Guide your children in doing this activity. Remind them of the precautionary measures. Tell them to be careful in handling the materials while performing the activity.

To the Learner:

Directions: Perform the activity below and answer the guide questions. Write your answers in your science notebook.

Activity 1: The Right Path

Objective: Describe how light travels.

What you need: flashlight, 3 pieces illustration boards (1/8 size), 1 piece thick cardboard, a partner (your sister or brother)

In the absence of a partner, a modeling clay could be used to create a “stand” to hold the illustration boards. In addition, this activity could be better observed when the room is dark (switch off lights, close doors, windows, curtains, etc.)

What to do:

1. Make a 2 inches hole at the center of the 3 pieces illustration boards.
2. Get a flashlight and aim it at a distant wall. Observe the path of light. Record your observation.
3. Block the path coming from the flashlight with a thick cardboard. Record your observation.
4. Hold each of the cardboard with a hole. Make sure the holes are aligned in such a way that the wall could be seen through the holes.
5. Aim the flashlight through the first hole. Observe what happens.

[illustration: six-panel sequence showing a hand making a hole in an illustration board, a flashlight beam aimed at a wall, a cardboard blocking the beam, and three boards with aligned holes with a flashlight behind them]

6. Misalign the middle cardboard your sister or brother is holding.
   Keep the light aimed at the cardboards. Observe what happens.

Guide Questions:

1. What happened to the light when the cardboards’ holes were aligned?
2. What happened to the light when the cardboards’ holes were not aligned?
3. Did the light form a straight line when you aimed it on the wall without blockage?
4. When you blocked the light with a thick cardboard, was it able to pass through the light? What was formed behind it?
5. When you aligned the cardboards with holes, was the light able to pass through? What was its path?
6. What can you say about the way light travels?

Congratulations! You have done well performing all the tasks. Proceed to the next to know more information about how light travels.

What is It

Points to Remember:

For a very long time, scientists were not sure exactly how light travels. Some say that light behaves like a wave while others claim that light behaves like a group of particles.

Then, they discovered that light travels as a wave in straight lines through empty space. Once light is produced, it will keep travelling in a straight line until it hits a material. Shadows are evidence of light traveling in straight lines. They are formed when the path of light is blocked.

During eclipse, the moon casts a shadow falling onto the Earth. Eclipse is a shadow in space. It happens when the light from the Sun is blocked by the Moon or the Earth.

[chart: diagram; eclipse of the Sun, showing the Sun at left, the Moon blocking its light, and the Earth at right with the Moon’s shadow falling on it]

Light travels very fast at nearly 300,000 km/s in vacuum space. Light is faster than sound. Unlike sound, which needs a medium (like solid, water or air) to travel through, light does not need a medium to propagate or move through and can travel in vacuum space.

What’s More

A. Directions: Write TRUE if the statement is correct and FALSE if it is not. Do it in your Science notebook.

1. Light needs a medium through which it can travel.
2. Fireworks show how light travels faster than sound.
3. Light travels faster in glass than it does in a vacuum.
4. Light travels in a straight line when it passes through a single medium.
5. Light rays could not be blocked and they could pass through all types of materials since they travel on a straight line.

B. Directions: Observe how light travels in the pictures. Write a check mark (√) if the flame will be seen and a cross mark (X) if not. Do it in your science notebook.

1.	2.
[illustration: lit candle, three cards with holes in a straight line to an eye] _____	[illustration: lit candle, three cards with the light path bent between the holes to an eye] _____
3.	4.
[illustration: lit candle, three cards with the light path bent between the holes to an eye] _____	[illustration: lit candle, first card with its hole placed away from the path, the light path bent between the holes to an eye] _____
5.	6.
[illustration: lit candle, three cards with the light path bent after the second card to an eye] _____	[illustration: lit candle, three cards with the light path in a straight line to an eye] _____

Great! You really learned well the lesson.

What I Have Learned

Directions: In one or two sentences, describe how light travels using the picture below. Write your answer in your science notebook.

[illustration: flashlight beam passing straight through four aligned cards with holes onto a dark wall]

What I Can Do

Directions: Read and answer the following questions. Write your answer in your Science notebook.

1. Why aiming laser pointer at a person’s head and eyes is harmful?
2. When you take a picture, in what direction will you position yourself with reference to the source of light?

Great job! After performing the activities about how light travels, you are now ready to answer the assessment.

Assessment

A. Directions: Read and answer the following questions. Write the letter of the correct answers in your science notebook.

1. Which of the following statement is TRUE?
   a. Light does not travel.
   b. Light travels in a curve line.
   c. Light travels in a straight line.
   d. Light reflects in opaque materials.

   
   

2. Light is a form of ___________ that is needed to support life on Earth.
   a. compression
   b. energy
   c. motion
   d. vibration

   
   

3. What evidence/s show/s that light travels in a straight line.
   a. Shadows are formed.
   b. Light passes through the holes which are aligned together.
   c. Rays of light are made of straight lines moving outwardly in all directions.
   d. All of these

   
   

4. What happens when you focus a pen light through a hole of a thick cloth?
   a. Light becomes brighter.
   b. Light changes direction.
   c. Light passes through the hole.
   d. Light is blocked or obstructed.

   
   

5. Which of these describes how light travels through an empty space?
   a. It travels in a straight line without stopping.
   b. It comes to a stop after it travels a certain distance.
   c. It changes direction often even if there are no objects.
   d. It travels straight but may change direction to avoid objects.

   
   

6. What kind of path does light take?
   a. It bounces off in all objects.
   b. It goes through in all objects.
   c. It curves around in all objects.
   d. It travels in a straight line until it hits something or goes through it.

   
   

7. Which word best describes how light moves?
   a. in circles
   b. straight line
   c. slowly
   d. faster through opaque objects

   
   

8. What do we call a material that light can travel through?
   a. air
   b. medium
   c. pathway
   d. water

   
   

9. We see shadow because light travels in a ___________ line.
   a. curved
   b. rainbow
   c. straight
   d. zigzag

   
   

10. Which of the following is true?
    a. Sound travels faster than light.
    b. Light travels faster than sound.
    c. Light travels at the same speed with sound.
    d. Light and sound do not travel in any medium.

    
    

B. Directions: The following pictures of objects are considered as sources of light. Using lines, draw the path of light of each object when they are lighted. Do it in your science notebook.

1. [illustration: table lamp]
2. [illustration: flashlight]
3. [illustration: flat-screen television]
4. [illustration: lit candle]
5. [illustration: light bulb]

Additional Activities

Directions: Cut out at least three (3) pictures of sources of light from old magazines and paste them in your Science notebook. Using lines, draw how light travels from its source.

Congratulations! You are now ready for the next lesson.

Lesson 2: How Sound Travels

Sound is all around us, all the time. Sometimes we ignore, sometimes we love and enjoy listening to it. Like light, sound is also very important in our life. People can communicate because of it. Animals and the things around us produce sound that make our surroundings more lively and interesting. This module will show you how sound travels in different materials.

What’s In

Directions: Draw the path of light in the following set-ups. Then, answer the questions. Do it in your science notebook.

1. [illustration: two flashlights in a box]
   How does light travel?

   
   
   
   
   

2. [illustration: lit candle, three cards labeled A, B and C, with an eye at the right]
   Can you see the flame of the candle in this set-up? Why?

   
   
   
   
   

3. [illustration: lit candle, three cards labeled A, B and C, with card B’s hole placed out of line, and an eye at the right]
   Can you see the flame of the candle in this set-up? Why?

   
   
   
   

What’s New

Note to Parent/Learning Facilitator: Guide your children in doing this activity. Remind them of the precautionary measures. Tell them to be careful in handling the materials while performing the activity.

To the Learner:

Directions: Perform the activity below and answer the guide questions. Write your answers in your science notebook.

Activity 1: How Sound Travels in Different Materials

What you need: a meter stick, a pencil, a big pail or can of water, 2 stones, a partner (your brother or sister)

What to do:

1. Get a meter stick and a pencil.
2. Hold the meter stick close to your ear. Have a partner scratch the other end of the meter stick with a pencil.
   • What happens?
3. Hold the meter stick away from your ear and repeat the activity.
   • Did you hear a softer or louder sound?
   • Where does sound travel faster? In solid or in air? Why do you think so?
4. Get a big pail of water. Get 2 pieces of stones and hit them together under water inside the pail. Now, hit them together out of water.
   • Did you hear sounds when you hit the two stones together outside the pail and underwater? Why?

[illustration: three panels showing a meter stick held to a student’s ear while a partner scratches the other end with a pencil, and the meter stick held away from the ear]

Good job! Just like light, sound also travels in different materials. Please proceed to the succeeding activities to know more about sound.

• Which sound was louder, in air or water? Why do you think so?

[illustration: two hands clapping, one with the hands under water in a glass and one with the hands in air above a covered container]

What is It

Points to Remember:

Sound is an energy produced by vibrations. When any material vibrates, it causes movement in the particles which are called sound waves. These sound waves keep going until they run out of energy.

The speed at which sound travels from one place to another depends upon the medium and how closely packed the particles are in the material. A medium is a substance that allows sound waves to travel through it. In a vacuum like the outer space, sound cannot travel so you cannot hear anything there.

As can be shown in the diagram below, sound waves travel the slowest through gases, faster through liquids, and fastest through solids. Sound travels most quickly through solids because the molecules of a solid are closer together and, therefore, can transmit the vibrations (energy) faster. Sound travels slowest through gases because the molecules of a gas are farthest apart. Sound also travels slower than light.

[chart: diagram; particle arrangement in gas, liquid, and solid, drawn as circles] Gas particles | Liquid particles | Solid particles

What’s More

A. Directions: Write TRUE if the statement is correct and FALSE if it is not. Write your answers in your science notebook.

1. Sound cannot travel in a vacuum.
2. Sound travels in solids, liquids and gas.
3. Sound travels fastest through liquid materials.
4. Sound travels faster through solid materials than gas.
5. Sound is not affected by the medium through which it travels.

B. Directions: Copy and complete the sentences using the words from the box. Do it in your science notebook.

closer speeds liquid gas medium solid

Sound can travel at different 1._________________ depending on the 2.__________________ it is travelling through. Sound travels faster in a 3.__________________ than it does in a 4.__________________ or in a 5.. This is because the particles in a solid are 6. together than they are in gas.

Did you get a perfect score? Good! Now, proceed to the next activity.

What I Have Learned

Directions: Using the representations of the three states of matter below, describe how sound travels through solid, liquid, and gas. Write two (2) to three (3) sentences in your science notebook.

[illustration: rows of tilted rectangles showing particles packed closely, moderately, and sparsely] Solid | Liquid | Gas

What I Can Do

Directions: Read and answer the following questions. Do it in your notebook.

1. Why do you think that most of the musical instruments are made up of solid materials?
2. What should a motorist do upon hearing the sirens of an ambulance or a fire truck behind him?
3. Why do doctors use stethoscope when examining on their patients?

Assessment

A. Directions: Read the questions and select the letter of the correct answer. Write your answers in your science notebook.

1. When sound travels in solids, vibration is __________.
   a. fast
   b. irregular
   c. moderate
   d. slow

   
   

2. How does sound travel through air?
   a. very fast
   b. very slowly
   c. in jumping motion
   d. fast in random manner

   
   

3. What affects the speed of the sound as it travels?
   a. person receiving it
   b. loudness of the sound
   c. the origin of the sound
   d. the nature of the material

   
   

4. Which of the following statements about sound is correct?
   a. Sound cannot travel through solids.
   b. Sound travels faster in air than in liquid.
   c. Sound travels faster in solids than in air.
   d. Sound is not affected by the medium through which it travels.

   
   

5. You are standing 5 meters away from your teacher. Why did you immediately respond when she called your name?
   a. Sound travels in solids.
   b. Sound travels in liquids.
   c. Sound travels in air.
   d. Sound travels in a vacuum.

   
   

6. Compared to light, sound travels __________.
   a. faster
   b. slower
   c. at the same speed
   d. There is not enough information to compare the two.

   
   

7. Which of the following would be most likely to transmit sound the best?
   a. steel in cabinet
   b. water in the ocean
   c. air in your classroom
   d. water in a swimming pool

   
   

8. On which place will we not be able to hear any sound?
   a. a theatre
   b. a closed room
   c. in a spaceship
   d. in the outer space

   
   

9. Sound waves travel fastest in ___________.
   a. air
   b. liquids
   c. solids
   d. vacuum

   
   

10. In which of the following does sound travel fastest?
    a. ice
    b. steam
    c. water
    d. Sound travels at the same speed in each of the above.

    
    

B. Directions: Describe how sound travels in each picture. Write your answer on your science notebook.

1. [illustration: drum being struck with two drumsticks]
2. [illustration: whale head near the water surface with concentric ripple rings]
3. [illustration: person lying with an ear pressed on a table with ripple lines on the table]
4. [illustration: two children seated facing each other, each holding a cup to the mouth, connected by a string]
5. [illustration: dog howling with concentric sound rings beside a standing man]

Additional Activities

Directions: There are 9 words hidden in this puzzle. Find the words and make meaningful sentence/s about how sound travels in different medium.

S	O	L	I	D	S	O	U	N	D
F	A	S	T	T	R	A	V	E	L
D	O	L	I	Q	U	I	D	T	W
J	R	U	F	A	S	T	E	R	I
M	E	D	I	U	M	U	G	A	S
G	F	A	S	T	E	S	T	E	S

Congratulations! You are done with the two lessons! You are now ready to move on to the next! Good luck!

Lesson 3: How Heat Travels

Heat is a form of energy and it is also very important in our life like light and sound. Heat keeps us warm, cooks our food, and does a lot of other things. Heat travels through different phases of matter. It travels through a solid, liquid and gas. How does transfer of heat happen? You will find out the answer to this question as you go through this lesson.

What’s In

Directions: Answer the following puzzle using the clues. Write your answers in your science notebook.

[chart: crossword puzzle grid; numbered squares 1 through 8 as printed]

Across: 2. needed by sound in order to travel 3. movement in particles when material vibrates 5. sound travels _________ 8. sound travels slowest in _________

Down:

1. up and down movement
2. sound travels fastest in _________
3. produced by vibrations
4. place where sound cannot travel

Check your answers using the key on the last page. I hope you got the correct answers. If not, it’s okay, you can go back to the previous lesson.

Just like light and sound, heat also travels. Proceed to the next activities that will enable you to describe how heat travels in solid, through liquid and gas. Good luck!

What’s New

A. Directions: In your notebook write two to three sentences in a given situation.

Some people say that putting a spoon in a cup of coffee would make it cool fast. Do you believe so? Why or why not?

[illustration: cup of coffee with a spoon standing in it, on a saucer]

You will be able to know if your answer is correct after you performed this activity.

Note to Parent/Learning Facilitator: Guide your children in doing this activity. Remind them of the precautionary measures. Tell them to be careful in handling the materials while performing the activity.

To the Learner:

B. Directions: Perform the activities below and answer the guide questions. Write your answers in your science notebook.

Activity 1: “You’re Hot and You’re Cold”

Objective: Describe how heat transfers in solid materials.

What you need: hot water, coffee mug, metal spoon, watch/ timer

What to do:

1. Fill the mug with hot water. Be extra careful when pouring hot water to the mug. Avoid spilling the hot water.

   
   

2. Place a metal spoon into the coffee mug.

   
   

3. Wait for about five minutes. Carefully feel the exposed end of the spoon. Slightly touch the outside surface of the mug, too. Record your observations in your Science notebook.

   
   

[illustration: pouring hot liquid into a mug with a spoon standing in it; mug with spoon labeled “5 Minutes”; hand touching the exposed end of the spoon]

Guide Questions:

1. What happened to the exposed end of the spoon when you touched it after five minutes?
2. What happened to the water inside the mug after five minutes?
3. What did you notice about the outside surface of the mug when you touched it? Why?
4. What conclusion about heat transfer can you formulate or draw out from this activity?

Activity 2: Up, Down, and Spin Around

Objective: Describe how heat travels in liquid.

What you need: 2 jars, cardboard, food color (blue and red)

What to do: Dissolve the food colors in separate jars. The red jar contains warmer water and the blue jar contains colder water. Place two jars with one on top of the other. A cardboard separates the two. After that, gently remove the cardboard. Observe and record what happens.

Now, reverse the jars’ positions then carefully remove the cardboard. Observe and record what happens.

[illustration: two jars stacked with a cardboard separating them; the same two jars with positions reversed]

Guide Questions:

1. What is the direction of the flow of warm water and cold water in the first set up?

   
   

2. What is the direction of the flow of warm water and cold water in the second set up?

   
   

3. What is the direction of heat flow in liquids?

   
   

4. If both jars are equally hot, what do you think will happen? Why?

   
   

5. If both jars are equally cold, what do you think will happen? Why?

   
   

6. What conclusion about heat transfer can you formulate or draw out from this activity?

   
   

How does the Sun dry your clothes when it’s too far away from Earth? Observe what happens to your clothes when exposed to sunlight.

[illustration: striped and dark shirts hanging on a clothesline under the sun]

[illustration: a man fanning smoke from a grill of live coals with a cloth]

How about sitting near a barbecue stand where live coals are used for grilling? What did you feel?

Activity 3: How heat is transferred through radiation?

Objective: Describe how heat is transferred through empty space or vacuum.

What you need: margarine, small plastic plate, spoon, place for direct exposure to sunlight

What to do:

1. Scoop a small portion of the margarine from its container using the spoon and place it on a small plate.
2. Place the plate with margarine under the Sun and observe for five minutes. Record your observation in your notebook.

[illustration: spoon scooping margarine onto a small plate; plate placed under the sun]

Guide Questions:

1. What happened to the margarine after exposing it to the Sun?
2. Why do you think it happened?
3. What do you think made the change on the margarine?
4. Predict what might happen to the margarine if it is continuously exposed to lamp/ Sun for a long period of time.
5. Why is it necessary that margarine or butter should be kept refrigerated?
6. Based on the activity, what can you say about heat transfer through radiation?

What is It

Points to Remember:

Heat can travel through solids by conduction. Conduction is the transfer of heat energy through direct contact between the heat source and another object. When this happens, heat energy moves out of the warmer object into the cooler object due to temperature difference. This heat transfer continues until both objects reach the same temperature (or thermal equilibrium).The figure at the right illustrates this.

[chart: diagram comparing temperatures; two panels labeled “HOT” and “COLD”, and below them a pair of panels labeled “EQUAL TEMPERATURE”]

[illustration: lighted candle with a spoon held over its flame]

The illustration below shows conduction. The heat from the lighted candle travels to the spoon (cold object) by direct contact causing the spoon to become hot.

Another example of conduction is shown below. The heat from water travels to the ladle by direct contact.

[illustration: a ladle stirring a pot of boiling water on a stove, with steam rising]

The water and the ladle are composed of small particles called molecules. Heat energy makes the molecules in the object move faster. The fast movements of the water molecules make the cooler ladle molecules move fast, too. As the fast moving particles collide with the slow moving particles, energy is transferred. As a result, more molecules move fast. This movement of water molecules continue until heat is spread uniformly throughout the materials.

There are materials that allow heat to flow through easily. We call them conductors. Metals are good conductors. That’s why we use them as cooking utensils because heat moves fast through the metal pan to the food. There are materials through which heat passes slowly or not at all. We call them insulators. Some insulators are wood, plastic and ceramic.

Heat Travels by Convection

Convection is the transfer of heat by the movement of the heated parts of a liquid or gas. Fluids include liquids and gases. Convection involves the motion of fluids in circulating currents. When water is heated in a kettle, the molecules at the bottom get heated first. The heated molecules move and rise pushing the top molecules, which are cold, to the bottom. The colder molecules sink, get heated at the bottom, and move up. Warm fluid rises and cold fluid sinks forming circulating currents. The heat moves from a higher temperature region to a lower temperature region. This movement continues until the fluid is evenly heated and you see bubbles forming.

[illustration: pot on a stove with curved arrows inside showing circulating currents of water]

This is also true with winds and breezes. Warm air rises, expands and cools. Cool air sinks. Convection is the reason why we have wind movements and local breezes. During daytime, air over the land is heated. It rises and expands. Cool air over the sea moves towards the land. That’s why you feel a refreshing breeze by the seaside during daytime.

Heat Travels by Radiation

Heat can also be transmitted across empty space or vacuum. This is called radiation. Radiation does not depend on the presence of matter to transfer heat. Radiant energy travels as waves through space. Heat waves hit Earth and cause warming. The Earth’s atmosphere traps the heat from the Sun.

Your house gets warm when the Sun’s waves or rays travel through a window and are trapped in your house. Heat waves are invisible. All warm objects radiate or give off heat waves. Some other examples of heat transfer by radiation are: the heat you feel when you are near a fire source, the heat given off by an electric heater, and the heat near a hot oven.

Amazing! I hope you got the concepts about heat transfer.

What’s More

A. Directions: Guess the Word. Solve the puzzle, use the clues below. Write your answer in your science notebook.

Down	Across
1 Heat can be transferred through _____ contact by the heat source and the body receiving the heat. 2 Heat transfer by the movement of heated parts of liquid or gas. 4 Heat is a form of _____. 5 Heat transfer through space 7 Heat transfer from a hot object to _____ object.	2 Heat transfer through direct contact 3 Materials that transfer heat easily 6 A form of energy that keeps us warm 8 Heat can travel through _____ in conduction. 9 The greatest source of heat energy.

[illustration: blank crossword grid with clue numbers 1 to 9 placed on it]

B. Directions: Identify how heat travels in each illustration whether it shows conduction, convection or radiation. Write your answer in your science notebook.

1. [illustration: hand touching the handle of a pot on a stove]
2. [illustration: pot of boiling water on a stove]
3. [illustration: sun shining over a house]
4. [illustration: frying pan with food on it]
5. [illustration: hand held near a lighted flame]

C. Directions: Identify what kind of heat transfer is described in the situations below. Choose your answer from the words listed in the box. Write your answer in your science notebook.

conduction convection radiation

1. campfire
2. boiling water
3. heating the iron
4. warming of nail over the lighted candle
5. drying of clothes under the heat of the Sun

D. Directions: Decode the hidden word by filling the blank with the correct letters as indicated by the following numbers. Then, write a sentence describing the meaning of the words that are formed.

A	B	C	D	E	F	G	H	I	J	K	L
1	2	3	4	5	6	7	8	9	10	11	12
M	N	O	P	Q	R	S	T	U	V	W	X
13	14	15	16	17	18	19	20	21	22	23	24
Y	Z
25	26

1. 
   8 5 1 20
2. 
   3 15 14 4 21 3 20 9 15 14
3. 
   18 1 4 9 1 20 9 15 14
4. 
   3 15 14 22 5 3 20 9 15 14
5. 
   20 5 13 16 5 18 1 20 21 18 5

You are really enlightened now! Great job! Now, let’s see if you can connect your learnings with real life situations.

What I Have Learned

Directions: Write TRUE if the statement is correct and FALSE if it is not. Then, change the part that makes the sentence incorrect. Do it in your science notebook.

1. Radiation is the heat transfer through space.
2. Heat transfer occurs in solid through conduction.
3. Radiation is the transfer of heat by movement of fluids.
4. Conduction is the transfer of heat through physical contact.
5. Heat moves from a lower temperature region to higher temperature region.
6. The method of heat transfer between the hot water and the metal spoon is called convection.

Way to go! This time let’s see if you can apply what you learned in real-life situations. Good luck!

What I Can Do

Directions: Answer the following questions briefly in your science notebook.

1. Why do we need to use a pot holder when we are removing hot casseroles or any hot cooking wares out of the stoves?
2. When we expose half of an iron nail outside on a sunny day, then we cover the other half with cartoon, the covered half still gets heated. Why is this so?
3. When is the best time for us to dry our clothes outdoors, during sunny day or a cloudy day? Why?
4. Staying too long under sunlight may damage our skin due to the radiation. What must we do to protect our skin from being hurt or injured by the heat of the Sun?

Amazing! You reason out so well. It’s time for the final test. Good luck!

Assessment

Directions: Write the letter of the correct answer in your science notebook.

1. What energy transfer is shown through direct contact of the heat source and the body receiving the heat?
   a. conduction c. heat
   b. convection d. radiation

   
   

2. Which of these activities show heat transfer by radiation?
   a. boiling egg c. refrigeration
   b. heating the wire d. lighting the room with a bulb

   
   

3. When one uses an exhaust fan, what kind of heat transfer is demonstrated?
   a. conduction c. nuclear
   b. convection d. radiation

   
   

4. Which of the illustrations show heat transfer?
   a. [illustration: two wine glasses] b. [illustration: stacked pieces of charcoal] c. [illustration: fire hydrant] d. [illustration: bowl of steaming soup with a spoon]

   
   

5. Which of the following DOES NOT show transfer of heat energy?
   a. boiling water in a kettle
   b. cutting paper in small pieces
   c. lighting a room with a fluorescent lamp
   d. placing a spoon in a cup of hot coffee

   
   

6. What is the direction of flow of heat transfer?
   a. from hot to cold c. from cold to hot
   b. from bottom to top d. from side to side

   
   

7. How is heat transferred in solid materials?
   a. through radiation c. through vacuum
   b. through conduction d. through convection

   
   

8. What happens to a liquid when heated?
   a. It remains the same. c. It increases in temperature.
   b. It increases in volume. d. It increases its water level.

   
   

9. What will happen to butter and chocolate bar when they are continuously exposed to heat?
   a. They may become heavier. c. They may melt.
   b. They may decrease in volume. d. They may expand.

   
   

10. When heat is transferred through gases it is called ___________.
    a. convection b. radiation c. conduction d. roasting

    
    

11. Which of the following is NOT true?
    a. Convection is the transfer of heat energy by circulating currents.
    b. Heat energy transfers from a colder body or cooler region to a hotter body or warmer region.
    c. Heat energy transfers by convection in liquids and gases.
    d. Conduction is the transfer of heat energy from molecule to molecule or atoms in an object.

    
    

12. During heating, the water at the bottom of a jar gets heated first and begins to rise. As warm water rises, cold water goes down. This shows what kind of heat transfer?
    a. conduction b. convection c. insulation d. radiation

    
    

13. You left a fork in a bowl of hot water. When you got the fork, you observed that it became hotter. What do you call the heat transfer involved in the situation?
    a. conduction b. convection c. insulation d. radiation

    
    

14. Which of the following shows convection?
    a. A spoon gets hot when left in a bowl of hot soup.
    b. A girl holding a hot spoon felt her fingers becoming warm.
    c. Larry feels his head and arms getting warm as he walks under the Sun.
    d. The hot surface of the land heats the air above it and the air becomes warm.

    
    

15. Grade IV pupils went camping. They lighted a bonfire and they felt their face and arms were getting warm. How did the heat from the fire transfer to the pupils?
    a. through radiation c. through insulation
    b. through convection d. through conduction

    
    

Additional Activities

Directions: Write a simple reflection about what you have learned in this module by completing these statements. Do it in your science notebook.

1. In this module, I discovered that___________________________.
2. The most exciting activity for me was_______________________.
3. The easiest lesson for me was ________________________ while the hardest was _______________________________________.
4. Next time, I want to learn more about_______________________.
5. I will use all that I have learned by _________________________.

Congratulations! You did great! Now, you may proceed to the next module. Good luck, keep learning and have fun!

Answer Key

[transcriber’s note: this page is printed rotated, and its two boxes are arranged so that the column order and section grouping could not be read with certainty. Items are transcribed in the order they appear on the page. Items marked [?] are uncertain.]

What I Can Do

1. Laser pointers can damage the person’s eyes.
2. Towards the source of light.

Assessment

1. c 2. b 3. d 4. c 5. a
2. d 7. b 8. b 9. c 10. b

B. (Straight lines moving outwardly from the source of light.)

Additional Activities

Pupils’ answers may vary.

LESSON 2 – How Sound Travels

What’s In

1. Light travels in a straight line. [?]
2. Yes, because the light from the candle will pass through straight to the aligned holes of the cardboard. [?]
3. No, because one cardboard is not aligned. [?]

[transcriber’s note: these three items concern light and appear to belong under LESSON 1; their position on the rotated page is uncertain]

What’s New

Activity 1: How Sound Travels in Different Materials

Answers to Guide Questions:

• I will hear a scratching sound.
• Yes
• Solid
• Yes, sound travels in water and air
• Water

What’s More

A.

1. TRUE 2. TRUE 3. FALSE 4. TRUE 5. FALSE

What I Know

A.

1. FACT 2. BLUFF 3. BLUFF 4. FACT 5. BLUFF
2. FACT 7. FACT 8. FACT 9. BLUFF 10. FACT

B.

1. conduction 2. radiation 3. convection 4. conduction 5. radiation

[transcriber’s note: the B items above do not match the light lesson and may belong to the heat lesson; their placement is uncertain]

LESSON 1 – How Light Travels

What’s In

A.

1. magnetic axis 2. magnetic poles 3. magnetic field

B.

1. repel 2. attract 3. repel 4. repel 5. attract 6. attract

[transcriber’s note: the What’s In items above are printed as magnet terms and their lesson assignment is uncertain]

What’s New

Activity 1: The Right Path

Answers to Guide Questions:

1. The light passed through.
2. The light did not pass through.
3. Yes
4. No, shadow was formed.
5. Yes, straight path.
6. Light travels in a straight line until it hits a material.

When light is blocked, a shadow is formed.

What’s More

A.

1. FALSE 2. TRUE 3. FALSE 4. TRUE 5. FALSE

B.

1. X 2. X 3. X 4. X 5. X 6. ✓

What I Have Learned

Light travels in a straight line until it hits a material. Shadows are formed when light is blocked.

LESSON 2 – How Sound Travels

What I Have Learned

Sound travels in solid, liquid, and gas. It travels fastest in solids, faster in liquid, and slowest in gas. Sound needs a medium to travel through. [?]

Exercise 2 – Fill in the blanks

1. speeds 2. medium 3. Solid 4. liquid 5. gas 6. closer

What I Can Do

1. Sound can travel easily in solids.
2. Move out of the way of the ambulance or fire truck because it could be an emergency.
3. To hear the heartbeat and sounds of the internal parts of the body.

Assessment

A.

1. a 2. b 3. d 4. c 5. c
2. b 7. a 8. d 9. c 10. a [?]

B.

1. Sound travels when the boy hit the drums.
2. The sound of the whale travels in water.
3. Sound travels when the boy hits the table.
4. Sound travels from the can, then through the string until it reaches the other end of the line.
5. The sound of the barking dog is heard by the man because sound travels in air.

Additional Activities

Words: Solids, Sound, Fast, Travel, Liquid, Faster, Fastest, Gas, Medium

Sound travels in different medium. It travels fast in gas, faster in liquid, and fastest in solids.

LESSON 3 – How Heat Travels

What’s In

1. vibration 2. medium 3. sound waves 4. solids 5. liquids 6. sound 7. vacuum 8. gases

What’s New

Activity 1: You’re Hot and You’re Cold

Answers to Guide Questions:

1. It became hotter.
2. It became colder.
3. It became hotter because heat from the water was absorbed by the mug.
4. Heat travels in solids from hot to cold materials.

Activity 2: Up, Down, and Spin Around

Answers to Guide Questions:

1. upward, towards the cold water
2. going down, towards the cold water
3. from hot to cold region
4. There will be no movement. Temperature differences make the movement of heat from hot to cold region.
5. There will be no movement. There is no difference in temperature.
6. Heat travels in water from hot to cold region.

Activity 3: How heat is transferred through radiation?

1. It melted.
2. The sun’s heat traveled in space and absorbed by the margarine.
3. The increase in temperature.
4. It will turn into liquid.
5. To maintain its low temperature and for it to remain solid.
6. Heat is transferred through space.

What’s More

A. (crossword)

• 1 across: direct
• 2 down: convection
• 3 across: conductors
• 4 across: energy
• 5 across: radiation
• 6 across: heat
• 7 down: cold
• 8 across: solids
• 9 across: sun
• across: conduction

B.

1. conduction 2. convection 3. radiation 4. conduction 5. radiation

C.

1. radiation 2. convection 3. conduction 4. radiation 5. radiation

D.

1. HEAT 2. CONDUCTION 3. RADIATION 4. CONVECTION 5. TEMPERATURE

What I Have Learned

1. TRUE
2. TRUE
3. FALSE: radiation should be changed to convection
4. TRUE
5. FALSE: high temperature to low temperature
6. FALSE: convection should be changed to conduction

What I Can Do

1. Pot holder protects us from very hot casseroles because it is a poor conductor of heat.
2. Heat travels through space and reaches the exposed part of the nail.
3. Sunny day because the sun’s rays can readily travel through space and dries the clothes.
4. We should use protective materials like shades and umbrella.

Assessment

1. a 2. d 3. b 4. d 5. b
2. a 7. b 8. c 9. c 10. a
3. b 12. b 13. a 14. d 15. a

Additional Activities

Pupils’ answers may vary.

References

Abutay, L., Bonao, D., Crucis, E., Eslabra, J., Gramaje, E., Guadamor, M., Hernandez, A., Ilagan, L., Llamera, F., Manawatao, R., Panganiban, H., Rojo, J., Tosco, R., & Zape J. (2015). Science grade 4: Learner’s material (1st ed., pp 186-206). Department of Education.

Abutay, L., Bonao, D., Crucis, E., Eslabra, J., Gramaje, E., Guadamor, M., Hernandez, A., Ilagan, L., Llamera, F., Manawatao, R., Panganiban, H., Rojo, J., Tosco, R., & Zape J. (2015). Science grade 4: Teacher’s guide (1st ed., pp 233-252). Department of Education.

DepEd-BEAM DLP (n.d.). Science and health: Sun as the primary source of heat and light – Module 50. Department of Education. https://lrmds.deped.gov.ph/

DepEd-BEAM DLP (n.d.). Science and health: How heat travels – Module 45. Department of Education. https://lrmds.deped.gov.ph/

Huiso, A.J. (2011). Warm Radiance. In Methods of heat transfer: Grade IV module. Department of Education. https://lrmds.deped.gov.ph/

For inquiries or feedback, please write or call:

Department of Education – Bureau of Learning Resources (DepEd-BLR) Ground Floor, Bonifacio Bldg., DepEd Complex Meralco Avenue, Pasig City, Philippines 1600

Telefax: (632) 8634-1072; 8634-1054; 8631-4985

Email Address: blr.lrqad@deped.gov.ph * blr.lrpd@deped.gov.ph