Science Works Grade 2

Science Works! 2TEXTBOOK

Science Works! 2Textbook

Philippine Copyright 2012 by DIWA LEARNING SYSTEMS INCAll 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 byDIWA LEARNING SYSTEMS INC4/F SEDCCO 1 Bldg.120 Thailand corner Legazpi StreetsLegaspi Village, 1229 Makati City, PhilippinesTel. No.: (632) 893-8501 * Fax: (632) 817-8700

ISBN 978-971-46-0306-6

Author

Claudine F. Guiking has a bachelor’s degree in behavioral science from Miriam College in Quezon City. She took up some graduate units in education at the University of the Philippines–Diliman before continuing her master’s degree in education with emphasis on international studies at the Philadelphia Biblical University, Asia Pacific Extension. She has seven years of teaching experience in both preschool and grade school.

Consultant

Antom V. Revilla finished his master’s degree in biology from Centro Escolar University. He obtained his bachelor’s degree in forestry, cum laude, from the University of the Philippines–Los Baños. Mr. Revilla was a supervisor of Christian Bible Baptist School of Excellence and Development. He has taught general science, biology, and scientific research at San Beda College–Manila from 1991–2008. He was also the subject area coordinator of the Natural Science Department of the said college from 2002–2008.

To the Pupil

Discovery and learning are part of your everyday life. Whether you are playing or studying, you are able to understand and learn about the things around you. This book, Science Works! 2, is meant to teach you different science concepts and skills in an exciting way.

Science Works! 2 will help you to be actively involved in learning concepts about the human body, plants, animals, Earth, sun, and many more. Science concepts and skills are best learned by engaging in activities and performing experiments. These activities will lead you to create your own questions, conduct your own investigations, and develop your own solutions to problems through reasoning and observation.

This book, which has been designed especially for you, includes the following components:

Sci-tionary presents an activity that introduces you to words or terms that you will encounter in the lesson.

Jump Start lists a set of guide questions that are expected to be answered as you go along the lesson.

Feed Your Mind provides the discussion of the science concepts to be learned in the lesson.

Science in Action presents experiments, cooperative learning activities, and individual or group projects that will apply the science concepts you have learned in Feed Your Mind.

Learning Area Integration relates a particular science lesson to the other subject areas such as English, mathematics, and social studies. This will help you appreciate how science is applied to other fields of study.

Rundown lists the important science concepts that should be remembered at the end of each lesson.

Brain Challenge presents 5- to 10-item quiz about the lesson.

Chapter Checkup includes exercises that cover all the topics discussed in a chapter.

Your Move presents an activity that will allow you to apply what you have learned to a real-life situation.

Aside from the components given above, some lessons in this book include these additional sections:

Incredible Facts presents interesting or extraordinary facts and trivia related to the science concept.

Proudly Pinoy features notable Filipino people, culture, products, and inventions.

Sci-tainment includes fun games and activities related to the science concept.

Exploring the Web provides links to online activities or exercises that you may access to help reinforce and enrich your learning.

Begin your journey and discovery now! Use what you will learn in this book and apply them to your everyday life.

Table of Contents

UNIT 1 The Human BodyChapter 1 Exploring Your Senses …………………………………………………. ..... 2Lesson 1 Discovery through Your Senses ………………………………………….. .......2 2 Exploring the Sense of Sight ..............................................................9 3 Exploring the Sense of Hearing ........................................................ 14 4 Exploring the Sense of Smell …………………………………………… ........ 19 5 Exploring the Sense of Taste …………………………………………… ......... 23 6 Exploring the Sense of Touch ………………………………………….. ........ 27 7 The Sense Organs Work Together ……………………………………... ...... 33 8 Caring for Your Sense Organs ......................................................... 37Chapter Checkup ............................................................................................... 42

Chapter 2 Knowing Your Body ................................................................. 46Lesson 1 The Foods the Body Needs .............................................................. 46 2 Growth and Change ......................................................................... 51 3 Similarities and Differences among Children .................................... 56 4 Keeping Yourself Healthy and Strong ............................................... 61Chapter Checkup ................................................................................................ 65Your Move ....................................................................................................... 67

UNIT 2 Plants and AnimalsChapter 3 Discovering Plants ................................................................... 70Lesson 1 Parts of Plants ................................................................................ 70 2 Groups of Plants ............................................................................. 75 3 Different Plant Habitats .................................................................. 80 4 How Plants Reproduce ................................................................... 84 5 Needs of Plants ............................................................................... 89 6 Uses of Plants ................................................................................. 93Chapter Checkup ............................................................................................... 98

Chapter 4 Understanding Animals ..........................................................100Lesson 1 Kinds of Animals ........................................................................... 100 2 How Animals Move ....................................................................... 105 3 What Animals Eat ......................................................................... 110 4 How Animals Reproduce .............................................................. 115 5 How Animals Adapt to Their Environment ................................... 119 6 How People Can Protect Animals .................................................. 125

Chapter Checkup ............................................................................................. 130Your Move ..................................................................................................... 131

Unit 3 Matter and Energy Chapter 5 Exploring Matter ................................................................... 134Lesson 1 Understanding Matter ................................................................... 134 2 Properties of Solids ........................................................................ 138 3 Properties of Liquids ..................................................................... 142 4 Properties of Gas .......................................................................... 145 5 Using Matter at Home ................................................................... 148Chapter Checkup ............................................................................................. 152

Chapter 6 Discovering Energy and Force ................................................ 155Lesson 1 Forms of Energy ............................................................................ 155 2 How Light Travels ......................................................................... 159 3 Sources of Heat .............................................................................. 164 4 How Sounds Are Produced ............................................................ 168 5 Electricity ..................................................................................... 173 6 The Force of Magnets ................................................................... 177Chapter Checkup ............................................................................................. 180Your Move ..................................................................................................... 183

Unit 4 Earth and SpaceChapter 7 Exploring Planet Earth ......................................................... 186Lesson 1 Earth, Our Home .......................................................................... 186 2 Landforms .................................................................................... 191 3 Bodies of Water ............................................................................ 197 4 Earth’s Natural Resources ............................................................. 202 5 Kinds of Weather .......................................................................... 208 6 Elements of Weather .................................................................... 213 7 Caring for Earth ............................................................................ 219Chapter Checkup ........................................................................................... 224

Chapter 8 Exploring the Solar System ................................................... 226Lesson 1 The Sun and Earth’s Movement .................................................... 226 2 Phases of the Moon ...................................................................... 232 3 Planets ......................................................................................... 237 4 Other Objects in the Solar System ................................................. 242Chapter Checkup ............................................................................................. 246Your Move ..................................................................................................... 247

The pictures show _________________________________________ .

Before, I know that ________________________________________.

1UNIT

How do you know about the things around you? Why can you enjoy them? What makes it possible for your body

to do several things at the same time? Your body works in amazing ways. It allows you to

explore and discover the world. In this unit, you will learn more about your body. Find out how wonderfully made you are.

Science Works! 22

Lesson 1

CHAPTER 1

Exploring Your Senses

Discovery through Your Senses

Find the correct words to complete the sentences. Write in the boxes the letters that match the given numbers. Use the given code below.

Code:1 2 3 4 5 6 7 8 9 10 11 12 13A B C D E F G H I J K L M

14 15 16 17 18 19 20 21 22 23 24 25 26N O P Q R S T U V W X Y Z

1. People learn about their surroundings through their

19 5 14 19 5 19 .

2. The 19 5 14 19 5 15 18 7 1 14 19

include the eyes, ears, nose, tongue, and skin. They receive messages from the surroundings and send them to the brain.

3. 14 5 18 22 5 18 5 3 5 16 20 15 18 19

send information to the brain.

The Human Body 3

In this lesson, you will be able to answer the following questions:

1. What are the five senses and five sense organs?2. What can your senses tell you about your

surroundings?3. How do the sense organs send messages to the brain?4. Why are the five senses important?

The sense organs are parts of your body that you use to understand the things around you. You use them to see, hear, smell, taste, and touch (feel). You can also sense changes in your surroundings. This is because each sense organ has nerve receptors. These receptors send messages or information to your brain. Your brain then tells you what you are seeing, hearing, smelling, tasting, or touching (feeling). It tells you how to respond to things around you. For example, if you accidentally touch something hot, the receptors in your hand send a message to your brain. You instantly pull away your hand so you will not burn it.

There are five main sense organs: eyes, ears, nose, tongue, and skin.

Your eyes allow you to see things. They can help you identify colors, sizes, and shapes of objects. You can sense

ear eye

skin

nosemouth

Science Works! 24

light, movement, and position of objects using your eyes. This way, you do not bump into objects.

Your ears allow you to hear music, voices of people talking, alarms, and many other sounds. You use them to tell if a sound is loud or soft.

Your nose allows you to detect scents and recognize the odor of things around you. Flowers, perfumes, popcorn, and freshly baked cookies smell good. The smoke coming from vehicles, and the odor of clogged canals and spoiled food smell bad.

Your tongue helps you taste and identify the different flavors of what you eat or drink. There are different kinds of tastes: sweet, sour, salty, bitter, and umami.

The skin all over your body allows you to feel the textures of objects. Imagine that you are walking along the beach on a hot day. The gentle wind is blowing on your face. You can feel the grainy hot sand on your feet. You can feel the cold ice cream in your mouth. You can touch the rough sides of the ice cream cone with your fingertips.

You use your sense organs to explore and understand your surroundings. You can enjoy delicious food, the sound of music, and the fragrance and colors of a flower because of your senses. You can know and respond to changes around you through your senses. For example, by smelling spoiled milk, you know that it is not safe to drink it anymore.

A cake tastes sweet.

Ampalaya tastes bitter.

Patis tastes salty.

A lemon tastes sour.

Cheese tastes umami.

The Human Body 5

Using My Sense Organs

Objectives: 1. Identify the five senses. 2. Use the senses to observe and describe given

objects. 3. Classify and group given objects through a

chart. 4. Enumerate ways in which the five senses

help in performing daily activities.

Materials: two paper plates, two fruits

Procedure:1. Observe each fruit. Describe its color, size, shape,

and texture.2. Write the descriptions in the given table.

Characteristics Fruit 1 Fruit 2ColorShapeSize

Texture

3. Look at your list of characteristics in the table above. Group the characteristics according to the senses you used to observe them.

Sense of

Sight

Sense of

Smell

Sense of

Taste

Sense of Hearing

Sense of

TouchFruit 1Fruit 2

Science Works! 26

Language

Look at the words you wrote to describe the fruits. They describe how the fruits look, feel, taste, and smell. These words are called adjectives. Use adjectives to describe other objects around you.

You learn about the world through your five senses. The five senses are sight, hearing, smell, taste, and touch (feel).

Sense organs have nerve receptors that send messages to the brain.

You see with your eyes. You can tell the colors, shapes, and sizes of objects.

You hear sounds with your ears. You can tell if sounds are loud or soft.

You smell with your nose. You can identify different odors.

You taste with your tongue. You can tell if a food is sweet, salty, sour, bitter, or umami.

You touch (feel) with your skin. You can tell if an object is hot, cold, soft, hard, rough, or smooth.

The Human Body 7

A. Complete each sentence. Choose the correct answer from the words in the box.

sense organs hearing nose nerve receptors smell taste

1. Your ___________________ include your eyes, ears, nose, tongue, and skin.

2. Your sense of _______________ tells you if a sound is loud or soft.

3. You can tell the flavor of food with your sense of _______________.

4. Your nose helps you ________________ good and bad odors.

5. Sense organs have ________________ that send messages to your brain.

Science Works! 28

B. Circle the object that you can describe or name using the given sense organ.

tongue

eyes

skin

nose

ears

The Human Body 9

Lesson 2 Exploring the Sense of Sight

O F Y Z X S L Y X QP M G J J L E J L LT U G K A A N E G TE N P B N Q S R K IR D E I R I S E V IN Y T N L B V T N LC E A A A I H A S TV X K G I U G L P TP H B Y I A K L V DU R E T I N A D O W

The following list of words are the parts of the eye. Look for these words in the puzzle and circle them.

1. lens

2. iris

3. retina

4. pupil


1. What are the parts of the eye?2. How do your eyes help you see?3. What are some conditions that affect one’s eyesight?4. Why is your sense of sight important?

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The eye is the sense organ for seeing. With your eyes, you can see shapes, colors, and sizes of objects. You can find light and tell direction and distance.

The eye has many parts that help you see. The iris is the colored part of the eye. The opening in the center of the eye through which light goes in is the pupil. It controls the amount of light that enters the eye. The light that passes through the pupil will then strike the lens. The lens focuses the light rays to the retina, the lining of the inner eye. The retina detects images and colors of objects. These images are turned into signals that are sent to the brain. The brain then tells you what you are seeing.

Some people cannot see things well because they have vision or eyesight problems. Nearsightedness is a condition in which things that are near can be seen clearly, but those that are far appear blurred or unclear. Farsightedness is a condition in which things that are far can be seen clearly, but those that are near are hard to see. Astigmatism makes images appear blurred or unclear. Nearsightedness, farsightedness, and astigmatism can be easily corrected by wearing eyeglasses or contact lenses.

iris pupil

lens vitreous gel

cornea

pupil (opening)

iris

ciliary body

optic nerve

retina

The Human Body 11

Incredible FactsHelen Keller (27 June 1880–1 June 1968) was just a baby

when she became both blind and deaf. In spite of her disabilities, she learned how to read and speak, and use sign language. She wrote many books and toured 39 countries to raise awareness and money for the visually impaired. Learn more about Helen Keller by visiting the Braille Bug Site on http://www.afb.org/braillebug/hKmuseum.asp (accessed on 20 June 2011).

Impaired Vision

Objectives: 1. Describe the common disorders of the eye. 2. Explain how eye disorders can affect people’s

daily activities. 3. Tell the importance of your sense of sight.

Materials: sunglasses, petroleum jelly, handkerchief, book, sheets of paper

Procedure:1. Rub a thin film of petroleum jelly on a pair of

sunglasses.2. Wear the sunglasses and do the following activities:

• Read a page from a book.• Make a paper airplane.• Write your name on a sheet of paper.• Walk from one end of the classroom and back to

your seat.

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Questions:1. How will you describe your vision while you were

wearing the sunglasses?2. Which activity did you find the most difficult to do?3. Which activities can you do even if your vision is

blurred?

• The eyes are your sense organs for seeing. They let you see sizes, shapes, colors, positions, and distances of objects.

• The eye has many parts. These include the iris, pupil, lens, and retina.

• Nearsightedness is a condition in which things that are near can be seen clearly, but those that are far appear blurred or unclear.

• Farsightedness is a condition in which things that are far can be seen clearly, but those that are near are hard to see.

• Astigmatism is a condition that causes things to appear blurred.

Math

Your eyes tell the shapes, colors, and sizes of objects. Observe different objects in your school. Identify their shapes and colors. Look for objects with the same shape. Then compare their sizes. Do this activity with a friend to double the fun. Observe objects together. Find the smallest square-shaped object or the biggest circular object. Have fun observing objects with your eyes!

The Human Body 13

How well can you recognize the shapes in the picture? Color the round objects red, the square objects brown, the rectangular objects blue, and the triangular objects orange.

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Lesson 3 Exploring the Sense of Hearing

Rearrange the letters to form the correct words. Use the given clues as guide.

___________ 1. r d m r e u a – it vibrates when sound waves reach it

___________ 2. d m i l e d e r a – it contains three tiny bones

___________ 3. i v r b t n o a i – very fast back-and-forth movement

___________ 4. u e r t o r a e – acts like a funnel and catches sound waves

Your ears help you hear sound. Sound is made when things vibrate or move back and forth very fast. Touch your throat and speak. Do you feel movements in your throat?


1. What are the parts of the ear?2. How do your ears help you hear?3. What are some conditions that affect one’s hearing?4. Why is your sense of hearing important?

The Human Body 15

The air around you is full of vibrations called sound waves. The outer ear works like a funnel. It catches sound waves and move them through the ear canal. At the end of the ear canal is the eardrum. The eardrum vibrates when the sound waves reach it. The eardrum passes these vibrations to the three tiny bones in the middle ear. Vibrations cause tiny receptors in the middle ear to wiggle. These vibrations create signals that are sent to the brain.

An illness, an ear infection, a head injury, or exposure to extremely loud sounds can damage some parts of the ear and can cause hearing loss. Hearing loss or hearing impairment happens when one or two ears can hear only a little sound or no sound at all. The word deafness is also used to refer to hearing loss.

People with hearing impairment need patience and understanding. You may need to speak more slowly or learn other ways to speak with them. Although their condition is unique, you will discover that they are no different from everyone else.

Sound waves enter the outer ear.

outer ear middle ear inner ear

ear canal eardrum three tiny bones

Science Works! 216

Incredible Facts Did you know that sound can be measured? The loudness

of sound is measured in decibels (dB). The sound of a person’s normal breathing is 10 dB. Heavy city traffic produces noise that registers 85 dB.

Find out the decibel levels of different sounds to avoid sounds that can damage your ears. Visit http://www.nidcd.nih .gov/health/education/decibel/decibel.asp (accessed on 13 June 2010).

Using Your Ears

Objectives: 1. Listen to and identify the source of sound. 2. Give the importance of having two ears.

Materials: meterstick, chalk, notebook, pencil, blindfold

Procedure:1. Work with a partner for this activity. 2. Pupil 1 will be the first to be blindfolded. He or she

will stand in one area of the room. Pupil 2 will mark this area using a piece of chalk.

3. Using the meterstick, your teacher will measure 2 meters away from the spot where pupil 1 stands. He or she will mark this spot A. Your teacher will measure again 2 meters away from spot A and mark this as spot B. He or she will measure again 2 meters away from spot B and mark this as spot C.

The Human Body 17

4. Pupil 2 will stand in any of spots A, B, or C and call out the name of pupil 1. Pupil 1 will identify the source of the sound by shouting A, B, or C.

5. Pupil 2 will change his or her spot eight times. Each time pupil 2 changes his or her spot, he or she will call out the name of pupil 1.

6. Pupil 2 will record the number of correct answers of pupil 1.

7. Repeat steps 3 and 4. This time, pupil 1 will cover his or her right ear with his or her hand.

8. Switch roles with your partner and repeat the activity.

Questions:1. When was it easier to identify the source of sound,

when ear was covered or not covered? Why? 2. How were your results similar or different from your

partner’s results?3. How would your life change if you could hear only

with one ear? How about if you could not hear at all?

Pupil 1

2 meters 2 meters 2 metersA B C

Pupil 2

Science Works! 218

• The sense organ for hearing is the ear. • Sound is made when things vibrate or move back and

forth very fast. • Sound waves travel through the ear and cause vibrations.

There are parts inside the ear that change these vibrations. These vibrations create signals that are sent to the brain.

• Continuous exposure to loud sounds is harmful and can cause hearing loss.

Label the parts of the ear. Choose your answers from the words in the box.

ear canal eardrum inner ear middle ear outer ear

1. 2.

3. 4. 5.

The Human Body 19

Lesson 4 Exploring the Sense of Smell

Draw a line to match each word in column A with its meaning in column B.


1. What are the parts of the nose?2. How does your nose help you smell?3. Why is the sense of smell important?

You learn about the world by seeing with your eyes and hearing with your ears. What does your nose do? You can also tell what is happening around you by your sense of smell. You know when something is burning or when your favorite food is cooking because you can smell their scents.

A B1. nasal cavity scent or smell2. nostril nice or enjoyable3. odor unlikable or horrible4. pleasant opening of the nose through

which you breathe5. unpleasant part of the nose that warms and

filters the air you breathe in

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The air around you can carry odors or scents. Some odors smell good or pleasant, such as the scent of perfume. Others smell bad or unpleasant, such as the scent of rotten eggs. You can recognize places and things by how they smell.

The scent of an object blends or mixes with the air. The scent enters your nostrils when you breathe in through your nose. The scent makes its way up to the roof of your nasal cavity (the part of the nose that warms and filters the air you breathe in). The scent is turned into signals that are sent to the brain. The brain tells what the smell is. It might be a pleasant smell like popcorn, or an unpleasant smell like dirty socks.

Have you noticed that you cannot recognize the smell of objects when you have a cold? The inside of your nose has a slippery and sticky lining called mucus. When you have a cold, mucus becomes thick. It covers tiny hairs in your nose. This prevents your nose from smelling things around you. Your sense of smell is connected to your sense of taste. This is why food seems tasteless when you have a cold.

Using Your Nose

Precaution: Pupils with asthma or allergy should not do this activity.

The Human Body 21

Objectives: 1. Observe and compare the ability of your nose to detect scent.

2. Tell the importance of the sense of smell.

Materials: variety of items with distinct scent (for example, cologne, kalamansi peeling, shampoo, bagoong), plastic containers (one for each item), notebook, blindfold

Procedure:1. Work with a partner for this activity. 2. Pupil A will be the first to be blindfolded. Pupil B

will hold the items and record his or her partner’s answers.

3. Pupil B will hold the first item under pupil A’s nose. (Note: Do not bring the item very close to your partner’s nose. Your partner may be allergic to some of the items.) Pupil A will identify the item. Pupil B will record his or her partner’s answers.

4. Repeat step 2 for the other items.

Questions:1. Was it easy for you to identify what the items are by

using your sense of smell?2. How were your results similar or different from your

partner’s results?3. How would your life be if you cannot smell?

Science Works! 222

Complete each sentence. Circle the correct word inside the parentheses.

1. Your (ear tongue nose) tells the smell of things around you.

2. Your sense of (hearing taste sight) is connected

to your sense of smell. 3. Pineapple, mango, and orange have a (pleasant

unpleasant) smell. 4. Baby powder smells (pleasant unpleasant). 5. Dirty clothes smell (unpleasant pleasant).

• The sense organ for smelling is the nose. • The air carries scent and enters your nose when you

breathe in air. The scent travels up your nose and is turned into signals. These signals are sent to your brain. Your brain tells you what the smell is.

• Your nose can tell whether an odor is pleasant or unpleasant.

The Human Body 23

Lesson 5 Exploring the Sense of Taste


1. What are the parts of the tongue?2. How does your tongue help you taste?3. Why is your sense of taste important?

As you enter your house, you notice that your mother is baking your favorite chocolate brownies. Snack time! You can imagine the taste of those warm brownies already. But how do you taste food?

You taste with your tongue. Your sense of taste helps you enjoy food. It also warns you if something is not safe to eat.

Take a close look at your tongue using a mirror. You will see that it is not smooth. Your tongue is covered with tiny

Arrange the letters to form the correct words. Use the given clues as guide.____________ 1. a i v s a l – a clear liquid, containing

water produced in the mouth____________ 2. s t a t e u b d s – they send

messages to the brain about how something tastes

Science Works! 224

papillae

“bumps” called papillae. Inside them are taste buds. You have about ten thousand of them! Your taste buds can sense different kinds of taste such as sweet, sour, salty, bitter, and umami. Umami is the meaty or savory taste you get mostly from cheese or meat.

When you put food in your mouth, your teeth begin to break the food into tiny pieces. The food mixes and dissolves with your saliva. Your saliva spreads the

flavor of food all over your tongue. Your taste buds pick

up the taste and send the message to the brain. Your brain tells you the taste of the food you are eating.

A picture of an onion-shaped taste bud.

Incredible FactsDysgeusia is a condition in which a person cannot identify

tastes of food correctly, has a poor sense of taste, or cannot taste anything at all. Some people lose their sense of taste as they get older. Others have dysgeusia because of an illness.

The Human Body 25

Taste Bud Challenge

Objectives: 1. Identify different food items using the sense of taste.

2. Use the sense of taste in comparing different flavors of food.

Materials: 5 different food samples (for example, sugar, salt, instant coffee, kalamansi extract, cheese), water, plastic cups (one for each food sample), a box of toothpicks, blindfold or big handkerchief

Procedure:1. Work with a partner for this activity. 2. Pupil A will be the first to be blindfolded, while

pupil B will help his or her partner.3. Pupil B will dip a toothpick in the first food sample.

He or she then places it on the tongue of pupil A. Pupil A will tell the taste and name the food sample.

4. Pupil B will record his or her partner’s answer in the table below. Pupil A will rinse his or her mouth between tastes by drinking water.

5. Repeat steps 2 and 3 for the other food samples.

Food Sample Taste Name of Food Sample

1234

6. Switch roles with your partner.

Science Works! 226

Questions:1. Were the food samples easy or difficult to identify

when you were blindfolded? Why?2. How were you able to differentiate the taste of one

food sample from the other?

• The sense organ for taste is the tongue. • Your tongue has many taste buds embedded in it. They

send signals to the brain.• The tongue can taste five basic tastes: sweet, sour, salty,

bitter, and umami.

Color the sweet foods red and the salty foods yellow. Check the sour foods. Box the bitter foods. Circle the food that tastes umami.

The Human Body 27

Lesson 6 Exploring the Sense of Touch

Complete the crossword puzzle. Read each clue below. Choose your answer from the words in word bank.

Word Bank

colddermis

epidermisheatpain

pressureskin

Across2. Discomfort due to injury or sickness4. To make or become warm or hot5. The bottom layer of the skin6. The top layer of the skin

Down1. This covers the entire body2. Force exerted on an object3. Having little or no warmth

1

2

3

4

5

6

Science Works! 228


1. What are the parts of the skin?2. How does your skin help you feel?3. Why is your sense of touch important?

The skin is the sense organ for touch. It covers your entire body. Your skin is made up of two layers. The top layer is called the epidermis. The bottom layer is called the dermis. The skin has receptors that feel pressure, heat, cold, and pain. When something comes in contact with your skin, these nerve receptors send signals to your brain. The brain tells you the effect of the touch and tells your body how to respond to that touch. For example, your brain tells you whether to grip or gently hold an object.

Your sense of touch or feeling also protects you. You can sense heat and cold. The nerve receptors in your skin warn you to pull your hand quickly from a hot stove or not to grip sharp objects.

hair

epidermis

dermis

The Human Body 29

You can tell the difference between rough and smooth, soft and hard, or wet and dry objects because of your sense of touch. Some parts of your skin are more sensitive than others. Your fingertips and cheeks respond to heat and cold more quickly than your elbows or knees do.

Careful hand pressure is used in molding a clay jar.

Receptor Tester

Objectives: 1. Name the parts of the body that are most sensitive to touch.

2. Observe and find out if sensitivity to touch varies in different parts of the body.

3. Tell the importance of your skin.

Materials: one paper clip, ruler, pencil

Procedure:1. Work with a partner for this activity.2. Carefully untwist the paper clip and then form it into

a U shape. (Ask the help of your teacher in doing this.) Use a ruler to measure the space between the ends of the

Science Works! 230

U-shaped paper clip. Make sure the ends are exactly 1 centimeter (cm) apart.

3. Have your partner close his or her eyes. Gently touch your partner with the bended paper clip on the first body part given in the table below. Ask your partner whether he or she feels one or two points of the paper clip.

5. Record your partner’s answer in the table. Write “1” under the given body part if your partner feels only one point. Write “2” if your partner feels two points.

6. Repeat steps 4 and 5 for the other parts of the body given in the table below.

7. Switch roles with your partner.

Body Part

Fingertip Wrist Back of the Hand Cheek Leg

Sensitivity

Questions:1. Which part of your body is the most sensitive? Why?2. Which part of your body is the least sensitive? Why?

The Human Body 31

Robot hand lets its user feel and touch objects.

Incredible Facts A team of scientists from Sweden

and Italy has developed Smart Hand. This is a robotic hand that offers a sense of touch for people who lost their hands. This device has 4 motors that enable the hand to move. It also has 40 receptors that let the person feel the object that the robot touches.

• The skin is your sense organ for touch or feeling. • The skin can sense heat, cold, pain, and pressure.• Some parts of the body, such as the cheeks and fingertips,

are more sensitive to touch than the other parts.

How does each object feel? Color two objects that the given word can describe.

cold

Science Works! 232

hard

hot

rough

smooth

soft

The Human Body 33

Lesson 7 The Sense Organs Work Together

Write the missing letters to complete the words.

1. The r i n controls everything in your body.

2. Some organs can o k together to help you do some activities.

3. The senses o l e t information from your surroundings.

Your five sense organs work together to help you do your daily activities. For example, when you eat, your eyes look for the food on the table. Your nose smells it. You can tell if it is hot or cold with your hand. Your tongue tastes the food. Your ears can sometimes hear the sound of crispy food being chewed.


1. Do the sense organs work together?2. Which sense organs work together in specific

activities?

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tastetouch

hearingsmell

sight

Senses Helping Each Other

Objectives: 1. Identify the sense organs you use in doing certain activities.

2. Use the five sense organs to do different activities.

Materials: sugar, evaporated milk, 2 bananas, crushed ice, chocolate powder, 1 liter drinking water, fork, plastic knife, spoon, plastic cups, sheet of paper

Procedure:1. Work together in groups to make a chocolate banana

drink. Use the given ingredients under Materials and write your own steps.

2. Copy the table on the next page on a separate sheet of paper. Write in the table the steps you followed and the sense organs you used for each step.

Your senses collect information from your surroundings. Each of your sense organs has parts that send information to your brain. The brain tells you what you have seen, heard, smelled, tasted, and touched.

Areas in the brain where each of the five senses is located.

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Steps Sense Organ(s) Used

Questions:

1. Were the steps you followed the same as those of the other groups?

2. How did your senses help you prepare the chocolate drink?

• The sense organs work together to give you information about your surroundings.

• Each sense organ has parts that send messages to the brain. The brain tells you what you see, hear, smell, taste, and touch (feel).

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Put a check ( ) mark under the sense organs that work together in each activity.

Activity Eyes Ears Nose Tongue Skin1.

2.

3.

4.

5.

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Lesson 8 Caring for Your Sense Organs

1. __ __ r __ a __ – a yellowish wax produced in the ear

2. s __ __ __ c r __ e n – a kind of lotion that protects the skin from sunburn

3. __ o __ s __ __ r i __ e – to add moisture to something


1. How can you take care of your sense organs?2. What are the things that can cause harm to your

sense organs?3. Why should you take care of your sense organs?

Caring for Your EyesDo you know that your eyes can actually

clean themselves? This happens when you blink. Blinking helps wipe the dust particles out and wash your eyes with tears.

Do not rub your eyes when they feel itchy. Rubbing can scratch your

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eyes. Gently wash your eyes with clean water to lessen or stop the itch.

If you are going out especially on a sunny day, wear sunglasses to protect your

eyes from the harmful rays of the sun.

Use good lighting when reading, writing, or using the computer. Make sure the light is not too bright.

Caring for Your EarsWhen listening to music using

headphones or earphones, turn the volume at a level that will not harm your ears. Avoid sleeping with your headphones or earphones on.

Use a damp cloth to clean your outer ears. Avoid using cotton tips to clean your ear canals. They can push the earwax deeper in your ears. Your ear canals have a way of pushing the earwax out of your ears.

Caring for Your NoseKeep your nose clean by wiping it gently

with tissue. Avoid nose-picking, rubbing, and blowing your nose hard. Do not insert tiny

objects in your nose. Blow your nose gently using tissue

or handkerchief. Throw used tissue in the trash can and wash your hands with soap

and water after.

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Caring for Your Tongue Brush your teeth regularly. Use a tongue

scraper to clean your tongue. Cleaning your tongue keeps your breath fresh and clean.

Avoid eating or drinking too hot or too spicy foods as these may burn or irritate your tongue.

Incredible FactsThe Chinese were the

first to use a toothbrush. They used a cattle-bone for the handle and wild boar (pig) hair for bristles. The wild boar hair was too stiff. It made the gums bleed so they changed it to horse hair. The invention of nylon (strong elastic material used in plastic) bristles in 1937 changed the face of toothbrush.

Caring for Your SkinYour skin covers and protects your entire body. There are

several ways you can take care of your skin. Take a bath regularly. Give your body a light scrub to

keep your skin healthy and clean. Use water and soap to wash your skin.

Cover any cut or wound on your skin with a medicated gauze and an antiseptic to keep dirt out and to prevent infection.

Moisturize your skin so it will not be dry, itchy, and flaky. Choose lotions that do not have strong scents.

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Long exposure to the sun (between 9:00 AM to 3:30 PM) can cause sunburn. Sunburn can be very painful. Wear a hat, a pair of sunglasses, and a long-sleeved shirt to protect you from the sun. Apply sunscreen if you will stay outdoors for quite a long time.

Eat healthy foods to help sharpen your five senses. Keep yourself safe and clean, and get plenty of rest and sleep to avoid getting sick. Always remember that a healthy body is a happy body.

Caring for My Senses

Objectives: 1. Identify the things that cause harm to your sense organs.

2. Name ways of caring for your senses.

Materials: 3 pieces of bond paper, coloring materials, pencil, old magazines

Procedure:1. Make a booklet showing ways to care for your sense

organs.2. Cut each bond paper in half. Fold and staple the

pieces of bond paper at the middle to make a booklet.3. The front page of the booklet is the title page. Use

one page for each sense organ.4. Cut out pictures showing different ways of caring

for your sense organs from magazines. You may also draw your own pictures. Describe each picture.

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• You need to care for your sense organs so that they will work properly.

• Wear sunglasses and apply sunscreen lotion to protect your eyes and skin from the sun whenever you go out during the day.

• Eating healthy foods, exercising, getting enough sleep, and maintaining cleanliness will keep your sense organs and entire body healthy.

Circle the picture of the child who shows care for his or her sense organs.

eyes

ears

nose

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A. Which sense organ is used to describe each object? Write the letter of the correct answer on the blank.

a b c d e

______ 1. The kalamansi juice is sour.______ 2. The loud sound of our school bell tells me it is

lunch time.______ 3. A crab’s shell is rough and hard.______ 4. My dog is big and has a brown fur.______ 5. My sister’s perfume has a floral scent.

tongue

skin

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B. Put a check ( ) mark on the picture that gives the correct answer. 1. Which is not a proper way of caring for the eyes?

2. Which practices are harmful to your ears?

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3. Which of the following should you use to clean your nose?

4. Which of the following shows proper care for the tongue?

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5. Which of the following shows proper care for the skin?

C. Color the sense organs that work together in each activity.1.

2. ears

eyes

skin

tongue

nose

nose

ears

tongue

skin

eyes

Education

Science Works Grade 2