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Smart Science
GRADE 3
TEXTBOOK


Philippine Copyright 2009 by DIWA LEARNING SYSTEMS INC
All rights reserved. Printed in the Philippines

Editorial, design, and layout by University Press of First Asia

No part of this publication may be reproduced or transmitted in any form or by any means
electronic or mechanical, including photocopying, recording, or any information storage and
retrieval systems, without permission in writing from the copyright owner.

        Exclusively distributed by
        DIWA LEARNING SYSTEMS INC
        4/F SEDCCO 1 Bldg.
        120 Thailand corner Legazpi Streets
        Legaspi Village, 1229 Makati City, Philippines
        Tel. No.: (632) 893-8501 * Fax: (632) 817-8700


       ISBN: 978–971–46–0089–8



REVIEWER
Marina Balce was a former assistant dean and associate professor at the College of Education, La
Salle College–Antipolo. She taught biological sciences for Psychology students and thesis writing for
graduating Education students in the same college. She was also a Trainee of the Japan International
Cooperation Agency (JICA) at the Aichi University in Nagoya, Japan, where she attended a special
training on Practical Work in Elementary School Science. Dr. Balce finished her bachelor’s degree in
Secondary Education major in Biology at the University of the East–Manila. She has a master’s degree
in Biology Education from the De La Salle University–Manila and a doctorate in Science Education
major in Biology from the University of the Philippines–Diliman.
To the Learner
      Do you ask yourself questions about the world you live in?
Do you wonder about what lies beyond the blue skies or what
rests below the seas? Do you ask questions about the blooming
trees and colorful flowers you see, the heat and cold you feel,
or the various scents you smell? Do you wonder about the sun,
the moon, and the stars? Your young, active mind has so many
questions because you are curious about so many things.

     This book will help you discover the answers to the
questions you have about yourself, the world, and everything
beyond it. This book will be your constant companion as you
unlock the many mysteries of life through various learning
experiences. Moreover, this book will teach you how to apply the
wonders of science to your day-to-day activities.

     Let this book help you find the answers to the questions you
have about yourself, your world, and your universe. Let this take
you a step closer to understanding life and in discovering the
wonders of science!
Unit 1          You and Your Body
Chapter 1       Your Senses
  Lesson 1      Your Eyes ................................................................................................... 2
  Lesson 2      How You See Things ................................................................................. 6
  Lesson 3      Common Eye Disorders and Diseases .........................................................9
  Lesson 4      Taking Care of Your Eyes ..........................................................................15
  Lesson 5      Your Ears ..................................................................................................18
  Lesson 6      Common Ear Diseases ..............................................................................23
  Lesson 7      Taking Care of Your Ears ...........................................................................27
  Lesson 8      Your Nose ................................................................................................31
  Lesson 9      Common Nose Diseases ...........................................................................35
  Lesson 10     Taking Care of Your Nose .........................................................................38
  Lesson 11     Your Tongue .............................................................................................40
  Lesson 12     Taking Care of Your Tongue .....................................................................44
  Lesson 13     Your Skin ..................................................................................................46
  Lesson 14     Common Skin Diseases .............................................................................50
  Lesson 15     Taking Care of Your Skin ..........................................................................53
  Think Back    ..................................................................................................................55
  Measure Up!   ..................................................................................................................55

Chapter 2       Growing Up
  Lesson 1      Signs of Growing Up ................................................................................57
  Lesson 2      You Grow Up with Friends .......................................................................62
  Lesson 3      You Become Smarter as You Grow ...........................................................65
  Lesson 4      Having a Healthy Body .............................................................................67
  Lesson 5      Diseases and Your Growth ........................................................................71
  Lesson 6      Growing Up with Fun ...............................................................................74
  Lesson 7      Your Environment Affects Your Growth ....................................................78
  Lesson 8      Good Health Habits ..................................................................................81
  Think Back    ..................................................................................................................84
  Measure Up!   ..................................................................................................................85

Unit 2          Animals and Plants
Chapter 3       Animals in the Environment
  Lesson 1      Animals Move in Different Ways ..............................................................88
  Lesson 2      Animal Habitat .........................................................................................92
Lesson 3      Kinds of Animals .......................................................................................97
  Lesson 4      How Animals Get Their Food .................................................................101
  Lesson 5      Food That Animals Eat ............................................................................105
  Lesson 6      Animals Have Needs ..............................................................................110
  Lesson 7      Useful and Harmful Animals ...................................................................114
  Lesson 8      Taking Care of Animals ...........................................................................118
  Lesson 9      Safety around Animals ............................................................................122
  Think Back    ................................................................................................................125
  Measure Up!   ................................................................................................................126

Chapter 4       Plants around You
  Lesson 1      Similarities and Differences among Plants ...............................................128
  Lesson 2      Where Plants Grow .................................................................................133
  Lesson 3      Parts of Plants .........................................................................................137
  Lesson 4      How Plants Grow ...................................................................................141
  Lesson 5      Importance of Plants ...............................................................................145
  Think Back    ................................................................................................................150
  Measure Up!   ................................................................................................................151

Unit 3          Matter, Energy, Force, and Motion
Chapter 5       Matter around You
  Lesson 1      Solids ......................................................................................................154
  Lesson 2      Liquids ....................................................................................................158
  Lesson 3      Gases ......................................................................................................162
  Think Back    ................................................................................................................164
  Measure Up!   ................................................................................................................165

Chapter 6       Light and Sound
  Lesson 1      Light Travels ...........................................................................................166
  Lesson 2      Light Bounces .........................................................................................171
  Lesson 3      Light Bends .............................................................................................173
  Lesson 4      Colors of White Light ..............................................................................176
  Lesson 5      How Sound Is Produced .........................................................................179
  Lesson 6      Loud and Soft Sounds .............................................................................182
  Lesson 7      Sound Travels .........................................................................................185
  Think Back    ................................................................................................................188
  Measure Up!   ................................................................................................................189
Chapter 7        Force and Motion
   Lesson 1      Making Objects Move .............................................................................191
   Lesson 2      The Force of a Magnet ............................................................................194
   Lesson 3      Earth’s Force ...........................................................................................197
   Lesson 4      Forces of Wind and Water ......................................................................200
   Think Back    ................................................................................................................204
   Measure Up!   ................................................................................................................205

Unit 4           Earth and Sun
Chapter 8        Soil and Water
   Lesson 1      Your Environment ...................................................................................208
   Lesson 2      Characteristics of the Soil ........................................................................211
   Lesson 3      Useful Soil ..............................................................................................215
   Lesson 4      Soil Pollution ..........................................................................................218
   Lesson 5      Caring for the Soil ...................................................................................222
   Lesson 6      Sources of Water .....................................................................................224
   Lesson 7      Uses of Water .........................................................................................229
   Lesson 8      Water Pollution .......................................................................................232
   Lesson 9      Using Water Wisely ................................................................................235
   Think Back    ................................................................................................................237
   Measure Up!   ................................................................................................................238

Chapter 9        The Weather and the Sun
   Lesson 1      Air Temperature, Wind, and Air Pressure ................................................240
   Lesson 2      Humidity, Clouds, and Precipitation .......................................................246
   Lesson 3      You and the Weather ..............................................................................252
   Lesson 4      Weather and the Environment .................................................................256
   Lesson 5      Protection from Harsh Weather Conditions .............................................259
   Think Back    ................................................................................................................263
   Measure Up!   ................................................................................................................264

Bibliograpy      ................................................................................................................266
Your body is composed of many parts. Some of these body parts are
your sense organs. These include your eyes, ears, nose, tongue, and skin.
You can see, hear, smell, taste, and feel because of your senses.

    Your body changes as you grow up. As this happens, many things
about you also change. You become more interested in the things around
you. You want to compare or differentiate things. You start to practice good
health habits. You start to make new friends. These things happen because
you are growing up.
Chapter 1
                             Your Senses
      It is good to observe the things around you.
      You see the sky in bright hue.
      And hear the cows that moo!
      You can smell the flowers in the garden
      Or taste your favorite food in the kitchen
      Or feel the cool breeze on the mountain.

      You see, hear, smell, taste, and feel.
      Your sense organs allow you to experience these in real!


      Lesson     1
                                                          Your Eyes




1. What is your organ for seeing?
2. What are the parts of your eyes and their functions?

     Your eyes are your organs
for seeing. You can see different
things around you because
of your eyes. You can see the
different colors of flowers. You
can watch the spider spin its
web. You can see your friends.
You can read books. You can
watch your favorite TV program.
What other things can you see
around you?


2    Smart Science 3
Parts of the Eye
1. Face your seatmate.
2. Look at one of his or her eyes.
3. Draw its shape.
    What is its color? _________
4. Look at the drawing below. Can you name the parts shown?
    Choose from the words in the box.
                                                     a. __________________
       pupil
                                                     b. __________________
       eyebrow
       iris                                          c. __________________
       eyelashes                                     d. __________________
       eyelid
                                                     e. __________________


     Each part of the eye has a          aqueous humor                    retina
function. There are parts that
protect the eyes. These are the           pupil                                 optic
eyelids, the eyelashes, and the                                                nerve
eyebrows. They protect the eyes
from dust, too much light, and          cornea
other things that can damage
them.                                     iris

     The inside of the eye has
                                            lens
other parts. Examine the drawing.                                          vitreous
                                                                            humor
It shows a longitudinal section of         eye muscle
the eye.
                                       Longitudinal section of the human eye
     The part of the eye that is
shaped like a ball is the eyeball. It is the part that we call the eye. It
contains a jellylike substance called the vitreous humor, which gives the
eye its round shape.

                                                             You and Your Body     3
The eyeball can move in its socket. The muscles that are attached to it
let the eye move. Close your eyes and gently touch your eyeballs as they
move up and down. What characteristics of the eyeball can you infer by
this action?
     Do you see the colored part of the eye? It is called the iris. The iris is
made up of muscles. At its center is the pupil, an opening that allows light
from the outside to enter the eye.
     Look at the drawings of the eyes below. Tell the difference between
the pupils of each pair of eyes.




In bright light, the pupils of the eyes       In dim light, the pupils of the eyes
become smaller.                               become larger.

    The muscles in the iris make the pupil smaller or bigger. In bright light,
the iris muscles tighten, making the opening (pupil) smaller. A smaller
opening prevents too much light from entering the eye. This way the eye is
protected. In dim light, the pupil becomes bigger to let in more light.
    Behind the pupil is the lens. Light can pass through it because it is
transparent. A tough, transparent material called the cornea covers the
lens. Between the lens and the cornea is a watery fluid called the aqueous
humor.
    At the back part of the eye is a light-sensitive layer called retina. The
cells in the retina translate the light that enters the eye into a signal. This
signal is then carried to the brain by the optic nerve for processing.




• The eyes are the sense organs for seeing.
• Eyelids, eyelashes, and eyebrows protect your eyes from dust, too much
  light, and other damaging things.
• The inside parts of the eyes are the iris, pupil, lens, cornea, vitreous
  humor, aqueous humor, retina, and optic nerve.
4     Smart Science 3
A. Match the items in Column A with those in Column B. Write only the
   letter of your answer.

         Column A                    Column B
   ______1. pupil                    a. covers the lens
   ______2. aqueous humor            b. an opening that allows light
   ______3. eyeball                     to enter
   ______4. cornea                   c. generally referred to as
   ______5. lens                         the eye itself
   ______6. eyelid                   d. colored part of the eye
   ______7. vitreous humor           e. gives the eye its round shape
   ______8. iris                     f. its transparency allows
                                         light to pass through it
                                     g. protects the eyes from dirt
                                     h. watery fluid between the
                                        cornea and the lens
                                     i. translates light into signal

B. Make a model of the eye. Use recycled materials to make the model.




                                                   You and Your Body    5

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Smstx3

  • 2. Smart Science GRADE 3 TEXTBOOK Philippine Copyright 2009 by DIWA LEARNING SYSTEMS INC All rights reserved. Printed in the Philippines Editorial, design, and layout by University Press of First Asia No part of this publication may be reproduced or transmitted in any form or by any means electronic or mechanical, including photocopying, recording, or any information storage and retrieval systems, without permission in writing from the copyright owner. Exclusively distributed by DIWA LEARNING SYSTEMS INC 4/F SEDCCO 1 Bldg. 120 Thailand corner Legazpi Streets Legaspi Village, 1229 Makati City, Philippines Tel. No.: (632) 893-8501 * Fax: (632) 817-8700 ISBN: 978–971–46–0089–8 REVIEWER Marina Balce was a former assistant dean and associate professor at the College of Education, La Salle College–Antipolo. She taught biological sciences for Psychology students and thesis writing for graduating Education students in the same college. She was also a Trainee of the Japan International Cooperation Agency (JICA) at the Aichi University in Nagoya, Japan, where she attended a special training on Practical Work in Elementary School Science. Dr. Balce finished her bachelor’s degree in Secondary Education major in Biology at the University of the East–Manila. She has a master’s degree in Biology Education from the De La Salle University–Manila and a doctorate in Science Education major in Biology from the University of the Philippines–Diliman.
  • 3. To the Learner Do you ask yourself questions about the world you live in? Do you wonder about what lies beyond the blue skies or what rests below the seas? Do you ask questions about the blooming trees and colorful flowers you see, the heat and cold you feel, or the various scents you smell? Do you wonder about the sun, the moon, and the stars? Your young, active mind has so many questions because you are curious about so many things. This book will help you discover the answers to the questions you have about yourself, the world, and everything beyond it. This book will be your constant companion as you unlock the many mysteries of life through various learning experiences. Moreover, this book will teach you how to apply the wonders of science to your day-to-day activities. Let this book help you find the answers to the questions you have about yourself, your world, and your universe. Let this take you a step closer to understanding life and in discovering the wonders of science!
  • 4. Unit 1 You and Your Body Chapter 1 Your Senses Lesson 1 Your Eyes ................................................................................................... 2 Lesson 2 How You See Things ................................................................................. 6 Lesson 3 Common Eye Disorders and Diseases .........................................................9 Lesson 4 Taking Care of Your Eyes ..........................................................................15 Lesson 5 Your Ears ..................................................................................................18 Lesson 6 Common Ear Diseases ..............................................................................23 Lesson 7 Taking Care of Your Ears ...........................................................................27 Lesson 8 Your Nose ................................................................................................31 Lesson 9 Common Nose Diseases ...........................................................................35 Lesson 10 Taking Care of Your Nose .........................................................................38 Lesson 11 Your Tongue .............................................................................................40 Lesson 12 Taking Care of Your Tongue .....................................................................44 Lesson 13 Your Skin ..................................................................................................46 Lesson 14 Common Skin Diseases .............................................................................50 Lesson 15 Taking Care of Your Skin ..........................................................................53 Think Back ..................................................................................................................55 Measure Up! ..................................................................................................................55 Chapter 2 Growing Up Lesson 1 Signs of Growing Up ................................................................................57 Lesson 2 You Grow Up with Friends .......................................................................62 Lesson 3 You Become Smarter as You Grow ...........................................................65 Lesson 4 Having a Healthy Body .............................................................................67 Lesson 5 Diseases and Your Growth ........................................................................71 Lesson 6 Growing Up with Fun ...............................................................................74 Lesson 7 Your Environment Affects Your Growth ....................................................78 Lesson 8 Good Health Habits ..................................................................................81 Think Back ..................................................................................................................84 Measure Up! ..................................................................................................................85 Unit 2 Animals and Plants Chapter 3 Animals in the Environment Lesson 1 Animals Move in Different Ways ..............................................................88 Lesson 2 Animal Habitat .........................................................................................92
  • 5. Lesson 3 Kinds of Animals .......................................................................................97 Lesson 4 How Animals Get Their Food .................................................................101 Lesson 5 Food That Animals Eat ............................................................................105 Lesson 6 Animals Have Needs ..............................................................................110 Lesson 7 Useful and Harmful Animals ...................................................................114 Lesson 8 Taking Care of Animals ...........................................................................118 Lesson 9 Safety around Animals ............................................................................122 Think Back ................................................................................................................125 Measure Up! ................................................................................................................126 Chapter 4 Plants around You Lesson 1 Similarities and Differences among Plants ...............................................128 Lesson 2 Where Plants Grow .................................................................................133 Lesson 3 Parts of Plants .........................................................................................137 Lesson 4 How Plants Grow ...................................................................................141 Lesson 5 Importance of Plants ...............................................................................145 Think Back ................................................................................................................150 Measure Up! ................................................................................................................151 Unit 3 Matter, Energy, Force, and Motion Chapter 5 Matter around You Lesson 1 Solids ......................................................................................................154 Lesson 2 Liquids ....................................................................................................158 Lesson 3 Gases ......................................................................................................162 Think Back ................................................................................................................164 Measure Up! ................................................................................................................165 Chapter 6 Light and Sound Lesson 1 Light Travels ...........................................................................................166 Lesson 2 Light Bounces .........................................................................................171 Lesson 3 Light Bends .............................................................................................173 Lesson 4 Colors of White Light ..............................................................................176 Lesson 5 How Sound Is Produced .........................................................................179 Lesson 6 Loud and Soft Sounds .............................................................................182 Lesson 7 Sound Travels .........................................................................................185 Think Back ................................................................................................................188 Measure Up! ................................................................................................................189
  • 6. Chapter 7 Force and Motion Lesson 1 Making Objects Move .............................................................................191 Lesson 2 The Force of a Magnet ............................................................................194 Lesson 3 Earth’s Force ...........................................................................................197 Lesson 4 Forces of Wind and Water ......................................................................200 Think Back ................................................................................................................204 Measure Up! ................................................................................................................205 Unit 4 Earth and Sun Chapter 8 Soil and Water Lesson 1 Your Environment ...................................................................................208 Lesson 2 Characteristics of the Soil ........................................................................211 Lesson 3 Useful Soil ..............................................................................................215 Lesson 4 Soil Pollution ..........................................................................................218 Lesson 5 Caring for the Soil ...................................................................................222 Lesson 6 Sources of Water .....................................................................................224 Lesson 7 Uses of Water .........................................................................................229 Lesson 8 Water Pollution .......................................................................................232 Lesson 9 Using Water Wisely ................................................................................235 Think Back ................................................................................................................237 Measure Up! ................................................................................................................238 Chapter 9 The Weather and the Sun Lesson 1 Air Temperature, Wind, and Air Pressure ................................................240 Lesson 2 Humidity, Clouds, and Precipitation .......................................................246 Lesson 3 You and the Weather ..............................................................................252 Lesson 4 Weather and the Environment .................................................................256 Lesson 5 Protection from Harsh Weather Conditions .............................................259 Think Back ................................................................................................................263 Measure Up! ................................................................................................................264 Bibliograpy ................................................................................................................266
  • 7. Your body is composed of many parts. Some of these body parts are your sense organs. These include your eyes, ears, nose, tongue, and skin. You can see, hear, smell, taste, and feel because of your senses. Your body changes as you grow up. As this happens, many things about you also change. You become more interested in the things around you. You want to compare or differentiate things. You start to practice good health habits. You start to make new friends. These things happen because you are growing up.
  • 8. Chapter 1 Your Senses It is good to observe the things around you. You see the sky in bright hue. And hear the cows that moo! You can smell the flowers in the garden Or taste your favorite food in the kitchen Or feel the cool breeze on the mountain. You see, hear, smell, taste, and feel. Your sense organs allow you to experience these in real! Lesson 1 Your Eyes 1. What is your organ for seeing? 2. What are the parts of your eyes and their functions? Your eyes are your organs for seeing. You can see different things around you because of your eyes. You can see the different colors of flowers. You can watch the spider spin its web. You can see your friends. You can read books. You can watch your favorite TV program. What other things can you see around you? 2 Smart Science 3
  • 9. Parts of the Eye 1. Face your seatmate. 2. Look at one of his or her eyes. 3. Draw its shape. What is its color? _________ 4. Look at the drawing below. Can you name the parts shown? Choose from the words in the box. a. __________________ pupil b. __________________ eyebrow iris c. __________________ eyelashes d. __________________ eyelid e. __________________ Each part of the eye has a aqueous humor retina function. There are parts that protect the eyes. These are the pupil optic eyelids, the eyelashes, and the nerve eyebrows. They protect the eyes from dust, too much light, and cornea other things that can damage them. iris The inside of the eye has lens other parts. Examine the drawing. vitreous humor It shows a longitudinal section of eye muscle the eye. Longitudinal section of the human eye The part of the eye that is shaped like a ball is the eyeball. It is the part that we call the eye. It contains a jellylike substance called the vitreous humor, which gives the eye its round shape. You and Your Body 3
  • 10. The eyeball can move in its socket. The muscles that are attached to it let the eye move. Close your eyes and gently touch your eyeballs as they move up and down. What characteristics of the eyeball can you infer by this action? Do you see the colored part of the eye? It is called the iris. The iris is made up of muscles. At its center is the pupil, an opening that allows light from the outside to enter the eye. Look at the drawings of the eyes below. Tell the difference between the pupils of each pair of eyes. In bright light, the pupils of the eyes In dim light, the pupils of the eyes become smaller. become larger. The muscles in the iris make the pupil smaller or bigger. In bright light, the iris muscles tighten, making the opening (pupil) smaller. A smaller opening prevents too much light from entering the eye. This way the eye is protected. In dim light, the pupil becomes bigger to let in more light. Behind the pupil is the lens. Light can pass through it because it is transparent. A tough, transparent material called the cornea covers the lens. Between the lens and the cornea is a watery fluid called the aqueous humor. At the back part of the eye is a light-sensitive layer called retina. The cells in the retina translate the light that enters the eye into a signal. This signal is then carried to the brain by the optic nerve for processing. • The eyes are the sense organs for seeing. • Eyelids, eyelashes, and eyebrows protect your eyes from dust, too much light, and other damaging things. • The inside parts of the eyes are the iris, pupil, lens, cornea, vitreous humor, aqueous humor, retina, and optic nerve. 4 Smart Science 3
  • 11. A. Match the items in Column A with those in Column B. Write only the letter of your answer. Column A Column B ______1. pupil a. covers the lens ______2. aqueous humor b. an opening that allows light ______3. eyeball to enter ______4. cornea c. generally referred to as ______5. lens the eye itself ______6. eyelid d. colored part of the eye ______7. vitreous humor e. gives the eye its round shape ______8. iris f. its transparency allows light to pass through it g. protects the eyes from dirt h. watery fluid between the cornea and the lens i. translates light into signal B. Make a model of the eye. Use recycled materials to make the model. You and Your Body 5