Smart Science GRADE 5TEXTBOOK

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

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ISBN: 978–971–46–0093–5

REVIEWERMarina 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 LearnerDo 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 The Reproductive, Respiratory, and Urinary SystemsChapter 1 The Human Reproductive System

Lesson 1 The Male and the Female Reproductive Systems .........................................2Lesson 2 Changes during Puberty ..............................................................................7Lesson 3 Menstrual Cycle ........................................................................................11Lesson 4 Taking Care of Your Reproductive Organs ................................................15Think Back .................................................................................................................17

Measure Up! .................................................................................................................18

Chapter 2 The Human Respiratory SystemLesson 1 Parts and Functions of the Human Respiratory System ..............................19Lesson 2 Inhalation and Exhalation ..........................................................................25Lesson 3 Common Respiratory Ailments ..................................................................29Think Back .................................................................................................................33

Measure Up! .................................................................................................................33

Chapter 3 The Human Urinary SystemLesson 1 Parts and Functions of the Human Urinary System ....................................35Lesson 2 How the Urinary System Works ................................................................39Lesson 3 Some Urinary Ailments .............................................................................43Think Back .................................................................................................................47

Measure Up! .................................................................................................................47

Unit 2 Animal and Plant GroupsChapter 4 The Animal Group

Lesson 1 What Animals Eat .....................................................................................50Lesson 2 Body Parts That Animals Use in Eating ......................................................54Lesson 3 Animal Adaptations ..................................................................................58Lesson 4 Vertebrates ................................................................................................63Lesson 5 Invertebrates .............................................................................................70Think Back .................................................................................................................76

Measure Up! .................................................................................................................76

Chapter 5 The Plant GroupLesson 1 The Needs of Plants to Produce Food ........................................................78Lesson 2 Photosynthesis ..........................................................................................85Lesson 3 Importance of Plants .................................................................................89Lesson 4 Plant Adaptations ......................................................................................93Lesson 5 Classifying Plants ......................................................................................97

Think Back ...............................................................................................................101

Measure Up! ...............................................................................................................102

Unit 3 Matter, Energy, and MachinesChapter 6 Changes in Matter

Lesson 1 Physical Changes ....................................................................................106Lesson 2 Chemical Changes ..................................................................................114Lesson 3 Agents Causing Changes in Matter ..........................................................118Lesson 4 The Changing Environment .....................................................................122Lesson 5 Controlling the Destructive Changes in the Environment .........................127Think Back ...............................................................................................................131

Measure Up! ...............................................................................................................131

Chapter 7 Electric EnergyLesson 1 Static Electricity .......................................................................................133Lesson 2 Electric Circuit ........................................................................................139Lesson 3 Series Connection and Parallel Connection .............................................143Lesson 4 Generation of Electric Energy ..................................................................147Lesson 5 Electricity and Magnetism .......................................................................151Lesson 6 Using Electric Energy Wisely ...................................................................155Think Back ...............................................................................................................158

Measure Up! ...............................................................................................................159

Chapter 8 MachinesLesson 1 Levers .....................................................................................................161Lesson 2 Classes of Levers .....................................................................................166Lesson 3 Inclined Planes .......................................................................................170Lesson 4 Wedges ..................................................................................................173

Lesson 5 Screws ....................................................................................................176

Lesson 6 Wheel and Axle ......................................................................................179Lesson 7 Pulleys ....................................................................................................182Lesson 8 Proper Use of Machines ..........................................................................185Think Back ...............................................................................................................187

Measure Up! ...............................................................................................................187

Unit 4 Earth and Its WeatherChapter 9 Rocks and Soil

Lesson 1 Characteristics of Rocks ..........................................................................190Lesson 2 Igneous Rocks: The “Hot” Rocks .............................................................195

Lesson 3 Sedimentary Rocks: The “Cool” or “Wet” Rocks ......................................199Lesson 4 Metamorphic Rocks: The “Changed” Rocks ............................................204Lesson 5 Rock Cycle .............................................................................................207Lesson 6 Weathering and Soil Formation ...............................................................211Think Back ...............................................................................................................214

Measure Up! ...............................................................................................................214

Chapter 10 Weather ConditionsLesson 1 Water Cycle ............................................................................................216Lesson 2 Sunlight and Weather .............................................................................220Lesson 3 Tropical Cyclones ...................................................................................225Lesson 4 Before, During, and After a Cyclone .......................................................230Lesson 5 Public Storm Warning Signals .................................................................233Lesson 6 Safety Precautions ...................................................................................237Think Back ...............................................................................................................240

Measure Up! ...............................................................................................................240

Unit 5 Our Solar SystemChapter 11 About the Sun

Lesson 1 The Sun, a Star ........................................................................................244Lesson 2 Sunspots .................................................................................................249Lesson 3 Uses of Solar Energy ...............................................................................251Think Back ...............................................................................................................253

Measure Up! ...............................................................................................................254

Chapter 12 The Solar SystemLesson 1 Members of the Solar System ..................................................................255Lesson 2 The Planets in Orbit ................................................................................260Lesson 3 Planets and Their Distances from the Sun ................................................263Lesson 4 Planets and Their Periods of Revolution ..................................................266Lesson 5 Asteroids, Meteoroids, and Comets .........................................................269Think Back ...............................................................................................................273

Measure Up! ...............................................................................................................274

Glossary .............................................................................................................................. 276Bibliography ........................................................................................................................ 279

Index ................................................................................................................................... 281

The human body is able to perform many tasks. These tasks are made possible by the different body systems. Although each body system performs a specific function, the different body systems work in close coordination with one another. They sustain and regulate different life processes such as reproduction, adaptation, growth, and development.

In this unit, you will study three important body systems—the reproductive, respiratory, and urinary systems. You will study the parts of these body systems and their functions. You will also learn how to take good care of them.

Unit 1 The Reproductive, Respiratory, and Urinary Systems

Male reproductive system Female reproductive system

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Chapter 1

Lesson 1The Male and the Female Reproductive Systems

The Human Reproductive SystemHave you ever wondered how a new human being develops inside the female

body? As you proceed with the lessons in this unit, you will be amazed to find out that life starts out as a fertilized cell. This cell is the result of the union of the male and female sex cells.

Find Out

1. What are the parts of the male and the female reproductive systems?2. What are the functions of each part?

Humans, being living things, are able to reproduce offspring of their own kind. No two offspring, however, are the same. The ability of humans to reproduce ensures their continued existence on Earth.

Humans have body parts called organs that enable us to reproduce. These organs have coordinated functions that form a body system, called the reproductive system. In this lesson, you will learn about the structures of the reproductive organs and their specific functions.

The reproductive system of males differs from that of females. Look at the two illustrations below.

ureter bladder

penisurethraforeskin

seminal vesicleprostate glandCowper’s gland

epididymis

sperm inside the testis

scrotum

ovaryfallopian tube

wall of uterus

vaginasperm cervix

uterusendometrium

ovum inside the ovary

ovum

3The Reproductive, Respiratory, and Urinary Systems

Each reproductive organ has a specific function in the reproductive process. Table 1.1 lists the parts of the male reproductive system.

Table 1.1 Parts of the Male Reproductive System and Their FunctionsOrgan Description/Location Function

Testis (plural: testes) usually consists of a pair; each testis consists of many highly coiled tubes or ducts surrounded by several layers of connective tissues; found inside the scrotal sac or scrotum

produces sperm cells and secretes the male sex hormone (testosterone)

Scrotal sac orscrotum

external saclike structure with temperature slightly lower than that of the rest of the body

holds the testes

Penis composed of spongy, erectile tissues; its head is covered by a foreskin, which can be removed during circumcision

deposits sperm into the vagina

Urethra a duct that runs through the length of the penis and opens to the outside

serves as a passageway for both sperm and urine; has an opening that closes to allow sperm and urine to pass one at a time

Epididymis long, narrow, flattened, highly coiled convoluted ducts lying on the edge of the posterior border of the testes

stores mature sperm and is the site where the sperm cells gain the ability to move, which is necessary for fertilization

Vas deferens (plural: vas deferentia)

a short muscular duct passageway of the sperm from the epididymis to the urethra; stores sperm

Prostate gland thumb-sized gland; consists of muscular and glandular tissues that lie around the base of the bladder

secretes a fluid that neutralizes the acidity of the vagina to ensure the survival of the sperm; aids in sperm motility

Cowper’s glands(bulbourethral glands)

a pair of pea-sized glands found along the urethra and below the prostate gland

secrete a fluid that may serve as a lubricant and urine neutralizer

Seminal vesicles a pair of glands found between the bladder and the rectum

secrete a fluid that contains fructose (energy source for sperm)

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Explore

The Male Reproductive System

Look at the diagram of the male reproductive system. Identify the different organs of the system. Try to trace the path that sperm cells take as they travel from the testes to the outside of the body. Write your answers on the blanks.

from the testes

Head – bears half of the male’s characteristics

Midpiece – contains substances that provide the sperm cells energy for swimming

Tail – for moving the sperm to reach

the egg

The male reproductive system is made up of different organs and glands. Some of these parts are involved in the production of sperm cells, while some are involved in the delivery of the sperm cells to the female reproductive system.

The human testes produce the male sex cells called the sperm. Sperm cells are stored in the epididymis. Three glands provide secretions that mix with the sperm cells to form the semen. These glands are the seminal vesicles, the prostate gland, and the Cowper’s glands.

The ability to produce sperm cells does not necessarily mean the ability to produce a new individual. The number and the quality of sperm cells also determine the capability of sperm cells to unite with female egg cells. Smoking, excessive alcohol intake, emotional stress, substance abuse, malnutrition, heredity, and exposure to toxins and chemicals are some of the factors that affect sperm number and quality. At present, there are products available to test sperm number and sperm quality. These products can be administered at home without the aid of a physician.

The parts of the female reproductive system differ from those of the male. These parts and their corresponding functions are listed in Table 1.2 on the following page.

outside

5The Reproductive, Respiratory, and Urinary Systems

1. Use the illustration to identify the organs of the female reproductive system. 2. Tell the function of each part. 3. Using a marker, trace the path of the egg cell from the ovary to the uterus.

Draw arrows to indicate direction.

Table 1.2 Parts of the Female Reproductive System and Their FunctionsOrgan Description/Location Function

Ovaries small, flattened, elongated organs on both sides of the uterus

alternately produce the female sex cells (eggs or ova) and secrete the female hormones (estrogen and progesterone)

Fallopian tubesor oviducts

a pair of ducts leading from the ovaries to the uterus

serve as pathways where ova travel from the ovary to the uterus

Uterus pear-shaped muscular organ found in the pelvic cavity

receives and holds the fertilized ovum that eventually develops into a fetus

Cervix neck of the uterus that opens to the vagina

serves as the passageway for menstrual flow; serves as a passageway for sperm

Vagina (also called the birth canal)

a thin-walled passageway through which the sperm can enter and swim to the fallopian tube

serves as a passageway for menstrual flow; serves as the passageway of the baby during birth

How much have you learned about the female reproductive system? Find out in the next activity.

Explore

The Female Reproductive System

c.__________

d.__________

e.__________

a.__________

b.__________

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There are two ovaries where the ova develop and mature. Each ovary is connected to the ends of the fallopian tubes. The lower end or “neck” of the uterus is the cervix. The vagina is the birth canal through which a baby is normally delivered.

Keep in Mind

• The fundamental male reproductive organs are the testes. Other organs of the male reproductive system merely store and transport sperm, which include the following: scrotal sac, epididymis, vas deferens, prostate gland, Cowper’s gland, urethra, and penis.

• The testes produce sperm.• The fundamental female reproductive organs are the ovaries. Other organs of the

female reproductive system are the following: fallopian tubes or oviducts, uterus, cervix, and vagina.

• The ovaries produce eggs.

Challenge Yourself

Your teacher will group the class into two. Each group will be given about two to three illustrations of the male and female reproductive systems. You will also be given a set of name cards of the female and the male reproductive organs. Find the parts in each of the given illustrations. The first group to correctly sort them out will be the winner.

LanguageThe word reproduce is a combination

of the prefix re-and the root word produce. Re-means “again.” For example, to reproduce means “to produce again,” as in “reproduce the sound” or “reproduce the page.” Note that when something is reproduced, the resulting object is usually the same as the original. In the life sciences, to reproduce means to produce individuals of the same kind.

You will later encounter scientific terms with the prefix re-like regenerate and recycle. Use context clues to determine their meanings. Also, try to make a list of scientific words with the prefix re-.