© Pelangi Publishing (Thailand) Co., Ltd. 2019 All rights reserved. No part of this publication may be reproduced, stored in any retrieval system or transmitted in any form or by any means without permission of Pelangi Publishing (Thailand) Co., Ltd. 2019
BCRB293048 PES+SCI P3TB_Open page.indd 1
ISBN 978-616-541-311-4 First Published 2562
5/4/2562 BE 16:30
Contents Chapter 1 Food, Nutrition and Digestion 1 A
Food and nutrition.............................................. 2
B
Digestive system................................................ 15
Chapter 2 Separation Techniques 22 A
Separating a mixture of solids........................... 23
B
Separation by magnets...................................... 27
C
Separating insoluble solids from liquids............. 29
Chapter 3 Static Electricity 38 A
Static electricity.................................................. 39
Chapter 4 Electric Circuits 47 A
Simple electric circuits....................................... 48
B
Series and parallel circuits................................. 54
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Chapter 5 Light 63 A
Umbra and penumbra........................................ 64
Chapter 6 Eclipses and Space Technology 73 A
Solar eclipse and lunar eclipse ......................... 74
B
Space technology.............................................. 80
Chapter 7 Rocks 89 A
Types of rocks and rock cycle ........................... 90
B
Uses of rocks and ores ..................................... 100
C
Fossils ............................................................... 104
Chapter 8 Wind and Monsoons 113 A
Wind................................................................... 114
B
Monsoons ......................................................... 120
Chapter 9 Natural Disasters and Greenhouse Effect 131 A
Natural disasters ............................................... 132
B
Greenhouse effect ............................................ 153
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Let’s Find Out !
Special features
Encourages students to find information and present their findings.
in this book STEM Activity Provides an activity that engages in the application of knowledge of scientists, mathematicians and engineers.
K.W. L .W Allows students to know what to look for while reading and to reflect on what they have learned.
Let’s Scan and Watch !
Let’s Think! Challenges students with questions that promote higher thinking skills.
Provides direct access to the relevant information on the Internet by scanning the QR codes given.
Helps students to master their scientific knowledge and skills.
Presents a powerful diagram to literally ‘map’ out all the concepts in the chapter.
4C’s of the 21st Century 4C’s The Skills are:
Let’s Laugh ! Makes learning science a fun thing.
Communication Sharing thoughts, questions, ideas and solutions. Collaboration Working together to reach a goal. Putting talent, expertise smarts to work.
Let’s Know More ! Presents extra information that is relevant to the concept learned.
Critical Thinking Looking at problems in a new way and linking learning across subjects and disciplines.
Glossary
Creativity Trying new approaches to get things done equals innovation and invention.
Lists and explains difficult terms used in the text.
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Chapter
1
Food, Nutrition and Digestion Food helps us to grow and gives us energy, but how do we get the energy we need from the food?
K.W. L .W What do I know about food, nutrition and digestion? 1. 2. 3.
K.W. L .W What else do I want to know about food, nutrition and digestion? 1. What are the nutrients in food? 2. How do we choose food that is suitable for our gender and age and is safe for our health? 3. How does our digestive system work? 4.
Food, Nutrition and Digestion
1
A
Food and nutrition
Food provides nutrients to our body. Nutrients are the substances needed by our body for good health. There are six types of nutrients, namely carbohydrates, proteins, fats, vitamins, minerals and water. Carbohydrates Carbohydrates are the body’s main source of energy. Foods rich in carbohydrates are high in energy. Foods rich in carbohydrates
Rice
Bread
Fruits
Noodles
Potatoes
Biscuits
Corn
An active person needs more carbohydrates than a less active person. If the person does not have enough carbohydrates, he feels tired easily. Fiber is a type of carbohydrates. Fiber cannot be digested by our body. Fiber helps the food we eat to move properly through our stomach and intestines, producing soft stool or feces. Without fiber, our stool will be hard and difficult to be passed out. A condition in which a person experiences difficulty in passing out stool is called constipation.
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Foods rich in fiber
Vegetables
Wholemeal bread
Fruits
Proteins Proteins are body-building nutrients. They are needed for growth and repair. Proteins can also provide energy, but only when the body does not have enough carbohydrates and fats. Foods rich in proteins
Fish
Meat
Milk
Eggs
Nuts
Beans
Cheese
Growing children, adolescents and expecting mothers need more proteins.
Let’s Know More ! • Excess proteins cannot be stored. They are broken down and passed out in urine. • Serious lack of proteins in a child’s diet can lead to an illness called Kwashiorkor. Children suffering from this illness usually have round faces and big abdomens. However, they have weak muscles. Kwashiorkor can have a long-term impact on a child’s physical growth and, in severe cases, affect mental development.
Food, Nutrition and Digestion
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Fats Fats are an important part of a healthy diet. They are another source of energy for our body. The layer of fats under our skin keeps us warm. Fats help to maintain healthy skin and hair. Fats are also a part of our body cells. Carbohydrates that are not used up are immediately stored as fats. Foods rich in fats
Cooking oil
Peanuts
Cheese
Butter
People living in cooler areas need more fats to keep them warm.
Vitamins Vitamins keep the body healthy. Our body needs them for growing and developing. They are needed in small amounts for the body to function properly. There are 13 types of vitamins and each of them has different functions. For example, vitamin C helps to keep our skin healthy and healing of wounds. Foods rich in vitamins
Fruits
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Vegetables
6
Egg
Milk
Minerals Like vitamins, minerals also help to maintain good health. They help the body to function properly. There are many kinds of minerals such as calcium and iron. Foods rich in minerals
Milk
Vegetables
Fish
Meat
Water Our body also needs water to stay healthy. Water helps to transport nutrients to cells, get rid of waste products from the body and control the body temperature. Foods containing water
Water
Fruit juices
Soup
Milk
Let’s Know More ! Our body is made up of 60% to 70% of water in terms of mass. This means if you weigh 30 kg, your body contains about 18 kg of water. Therefore, water is very important to us. We can live for a few weeks without food, but we will die in a few days without water.
Food, Nutrition and Digestion
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Does your dinner contain all the six nutrients? 1. List down the food you took last night in the table below. Food
Carbohydrates Proteins Fats
Rice
Vitamins
Minerals
Water
✓
2. Put a tick (✓) in the column if the food contains the nutrient mentioned. 3. Did you eat all the nutrients needed by your body?
4. Does your food also contain fiber? Which of your food has fiber?
5. Did you have plenty of water yesterday? How many cups of water did you drink?
6. What is your conclusion for this activity?
Let’s Know More ! We are advised to eat a variety of foods, not just a few kinds of foods. This is because different kinds of foods contain different vitamins and minerals needed by our body.
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Nutrients in food Different foods contain different nutrients.
Candies contain only carbohydrates.
Apples contain vitamins, carbohydrates, minerals, water and fiber.
A plate of fried rice contains carbohydrates, fats, proteins, vitamins and minerals.
Eggs contain lots of proteins and fats and some vitamins and minerals.
If you buy packed or canned food, the nutrients in the food are stated on its label. They are listed under its nutrition facts or nutrition information.
The nutrition facts show the amount of carbohydrates, proteins fats, vitamins, minerals and fiber that we can get from eating the bread.
It is important to know the nutrients in the food we eat. This will help us in deciding which food to eat more and which food to eat less.
Food, Nutrition and Digestion
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Food additives Some foods may contain food additives. Food additives are substances added to food to maintain or improve its taste, texture and appearance. There are many types of food additives such as food colorings, food flavorings and preservatives. Food additives are usually used in junk food to make it looks more attractive, tastes better and lasts longer.
Junk food contains food additives.
There are different types of food additives in this lollipop such as food flavoring and food colorings.
Eating too much food that contains food additives is harmful to our health. Therefore, we should avoid or reduce the consumption of food containing food additives, especially junk food.
Let’s Find Out ! Look at the labels of the packed or canned food that you have at home. Are there any food additives in the food? Find out the types of food additives and their uses from the Internet. Find out also why we should not consume too much of these foods. Make a multimedia presentation and share your findings with your friends.
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Energy requirement and food Food gives us energy. This energy value in food is measured in calories or
joules per the amount of food. Fats are the most concentrated source of energy, followed by proteins and carbohydrates.
Different foods contain different energy values. Here is a list of energy value of some local food. Food
Quantity
Energy value (calories)
Egg
1 medium size
78
White bread
1 piece
79
Banana
1 medium size
105
Orange
1 medium size
45
Low-fat milk
1 glass
108
Pad Thai
1 plate
940
Fried rice with egg
1 plate
313
Fish and chips
1 plate
850
Tomyam gong
1 bowl
143
Each person needs a different amount of energy depending on his or her age, gender and activity level. Age 7 12
17
60
Gender
Activity level
Energy requirement (calories)
Male
Moderate
1600
Female
Moderate
1500
Male
Moderate
2250
Female
Moderate
2000
Male
Moderate
2290
Female
Moderate
2100
Male
Active
3300
Female
Active
2400
Male
Moderate
2100
Female
Moderate
1850
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Are you taking enough energy as required? 1. Record the food that you have in one day in the table below. Meal
Food
Quantity
Energy value (calories)
Breakfast
Lunch
Dinner
Total energy value 2. Find out the energy value of each food. Fill up the table and find the total energy value you have taken. 3. What is your energy requirement?
4. Does your energy intake match your energy requirement?
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