QR Code Full Colour Pages! Chong Chee Sian & Nor Azlina Mohd Arif Harlina Hayati Salaton & Nor Mazliana Abdul Hashim Science PELANGI KC117944 Form 1.2.3 KSSM
iiii Form 1 CHAPTER 1 Introduction to Scientific Investigation 1 1.1 Science is Part of Daily Life 2 1.2 Your Science Laboratory 4 1.3 Physical Quantities and Their Units 7 1.4 The Use of Measuring Instruments, Accuracy, Consistency, Sensitivity and Errors 9 1.5 Density 15 1.6 Steps in a Scientific Investigation 18 1.7 Scientific Attitudes and Values in Carrying Out Scientific Investigation 19 CHAPTER 2 Cell as the Basic Unit of Life 20 2.1 Cell-Structure, Function and Organisation 21 2.2 Cell Respiration and Photosynthesis 29 CHAPTER 3 Coordination and Response 33 3.1 Homeostasis in Living Things 34 CHAPTER 4 Reproduction 38 4.1 Sexual and Asexual Reproduction 39 4.2 Human Reproductive System 42 4.3 The Menstrual Cycle 45 4.4 Fertilisation and Pregnancy 47 4.5 Factors Affecting the Development of a Foetus and Baby 49 4.6 Infertility and Contraception 51 4.7 Plant Reproduction 52 CHAPTER 5 Matter 59 5.1 Matter in Nature 60 5.2 Three States of Matter 62 CHAPTER 6 Periodic Table 68 6.1 Classification of Elements 69 6.2 Mixtures 73 6.3 Compounds 76 CHAPTER 7 Air 80 7.1 Composition of Air 81 7.2 Combustion 85 7.3 Air Pollution 87 00 Content Ranger Sc.indd 2 22/06/2023 2:53 PM
iii CHAPTER 8 Light and Optics 89 8.1 The Use of Mirrors 90 8.2 Properties of Light 92 8.3 Reflection of Light 93 8.4 Refraction of Light 94 8.5 Dispersion of Light 96 8.6 Scattering of Light 97 8.7 Addition and Subtraction of Light 99 CHAPTER 9 Earth 103 9.1 The System and Structure of the Earth 104 9.2 Composition of the Earth 108 9.3 Main Processes of the Earth 109 9.4 Geohazard Phenomena 111 9.5 Age of Earth 115 9.6 Earth’s Resources and Applied Geology 117 Form 2 CHAPTER 1 Biodiversity 120 1.1 Diversity of Organisms 121 1.2 Classification of Organisms 122 CHAPTER 2 Ecosystem 126 2.1 Energy Flow in an Ecosystem 127 2.2 Nutrient Cycles in an Ecosystem 128 2.3 Interdependence and Interaction among Organisms, and between Organisms and the Environment 129 2.4 Role of Humans in Maintaining a Balanced Nature 133 CHAPTER 3 Nutrition 134 3.1 Classes of Food 135 3.2 Importance of a Balanced Diet 137 3.3 Human Digestive System 139 3.4 Process of Absorption and Transportation of Digested Food and Defaecation 141 CHAPTER 4 Human Health 144 4.1 Infectious and Non-infectious Diseases 145 4.2 Body Defence 148 CHAPTER 5 Water and Solution 151 5.1 Physical Characteristics of Water 152 5.2 Solution and Rate of Solubility 155 5.3 Water Purification and Water Supply 158 CHAPTER 6 Acid and Alkali 160 6.1 Properties of Acids and Alkalis 161 6.2 Neutralisation 165 CHAPTER 7 Electricity and Magnetism 167 7.1 Electricity 168 7.2 Flow of Electric Current in a Series Circuit and Parallel Circuit 174 iii 00 Content Ranger Sc.indd 3 22/06/2023 2:53 PM
iv 7.3 Magnetism 176 CHAPTER 8 Force and Motion 180 8.1 Force 181 8.2 Effects of Force 183 CHAPTER 9 Heat 193 9.1 Relationship between Temperature and Heat 194 9.2 Heat Flow and Thermal Equilibrium 195 9.3 Principle of Expansion and Contraction of Matter 198 9.4 Relationship between Types of Surface of Object and Heat Absorption and Emission 201 CHAPTER 10 Sound Waves 203 10.1 Characteristics of Sound Waves 204 10.2 Loudness and Pitch of Sound 206 10.3 Phenomenon and Application of Reflection of Sound Waves 208 CHAPTER 11 Stars and Galaxies in the Universe 210 11.1 Stars and Galaxies in the Universe 211 CHAPTER 12 Solar System 214 12.1 Solar System 215 CHAPTER 13 Meteoroid, Asteroid, Comet 222 13.1 Other Objects in the Solar System, such as Meteoroids, Asteroids and Comets 223 Form 3 CHAPTER 1 Stimuli and Responses 226 1.1 Human Nervous System 227 1.2 Stimuli and Responses in Humans 228 1.3 Stimuli and Responses in Plants 237 1.4 Importance of Responses to Stimuli in Animals 240 CHAPTER 2 Respiration 242 2.1 Human Respiratory System 243 2.2 Movement and Exchange of Gases in the Human Body 246 2.3 Health of Human Respiratory System 248 2.4 Adaptations in Respiratory Systems 250 2.5 Gaseous Exchange in Plants 252 CHAPTER 3 Transportation 255 3.1 Transport System in Organisms 256 3.2 Blood Circulatory System 256 3.3 Human Blood 261 iv 00 Content Ranger Sc.indd 4 22/06/2023 2:53 PM
v 3.4 Transport System in Plants 264 3.5 Blood Circulatory System in Animals and Transport System in Plants 268 CHAPTER 4 Reactivity of Metals 269 4.1 Variety of Minerals 270 4.2 Reactivity Series of Metals 271 4.3 Extraction of Metals from their Ores 275 CHAPTER 5 Thermochemistry 277 5.1 Endothermic and Exothermic Reactions 278 CHAPTER 6 Electricity and Magnetism 280 6.1 Generation of Electricity 281 6.2 Transformer 286 6.3 Transmission and Distribution of Electricity 288 6.4 Calculate the Cost of Electricity Consumption 294 CHAPTER 7 Energy and Power 298 7.1 Work, Energy and Power 299 7.2 Potential Energy and Kinetic Energy 301 7.3 Principle of Conservation of Energy 303 CHAPTER 8 Radioactivity 306 8.1 Discovery of Radioactivity 307 8.2 Atom and Nucleus 311 8.3 Ionising Radiation and Non-ionising Radiation 312 8.4 Uses of Radioactive Radiation 316 CHAPTER 9 Space Weather 317 9.1 Activities of the Sun that Affect Earth 318 9.2 Space Weather 321 CHAPTER 10 Space Exploration 323 10.1 Development in Astronomy 324 10.2 Development of Technology and its Application in Space Exploration 325 v https://qr.pelangibooks.com/?u=k71Q6PmA UASA Model Paper Form 2 & Answers https://qr.pelangibooks.com/?u=y7Afs9Uh UASA Model Paper Form 1 & Answers https://qr.pelangibooks.com/?u=F220cjyw UASA Model Paper Form 3 & Answers 00 Content Ranger Sc.indd 5 22/06/2023 2:53 PM
1 Fields and Careers in Science Science – A knowledge discipline that involves scientific observation and investigations of all things or natural phenomena. Biology Physics Chemistry Geology Meteorology Astronomy Doctor Microbiologist Botanist Engineer Physicist Teacher Pharmacist Chemist Forensic scientist Research officer Meteorologist Geologist Mineralogist Geoscientist Astronomer Astronaut Steps in Scientifc Investigation Identify the problem Make a conclusion Write a report Make a hypothesis Plan the experiment Conduct the experiment Analyse and interpret data Collect data CHAPTER INTRODUCTION TO SCIENTIFIC INVESTIGATION Form 1 1 i-THINK Gallery Theme 1: Scientific Methodology 01 Ranger Science Form 1.indd 1 22/06/2023 2:54 PM
Science Form 1 Chapter 1 Introduction to Scientific Investigation 2 Form 1 Form 1 What is Science? 1. Science is a knowledge discipline that involves scientific observations and investigations of all things or natural phenomena. 2. Natural phenomena are things or events that take place naturally in nature. Human growth Tornado Germination of seed Ebb and flow of the ocean Diagram 1.1 Examples of natural phenomena Importance of Science in Daily Life 1. Knowledge of science will enable humans to understand and solve problems related to natural phenomena that happen. 2. Table 1.1 explains the importance of science for humans with examples. Table 1.1 Importance of science with examples Importance Example (a) Understand ourselves, the environment and appreciate God’s creation Research in the fields of biology and chemistry help us to understand the characteristics of living things. (b) Make life more comfortable and simpler New creations and discoveries can produce electrical instruments that make our daily life easier. (c) Invent machines and produce various products Automatic machines and computers help us to complete routine work quickly. (d) Communication becomes easier and faster Two-way telecommunication systems through the telephone and the internet bridges human relationships. Fields and Careers in Science 1. Science can be divided into several fields. 2. Table 1.2 shows the description of several fields in science as well as the related careers. 1.1 Science is Part of Daily Life 01 Ranger Science Form 1.indd 2 22/06/2023 2:54 PM
Science Form 1 Chapter 1 Introduction to Scientific Investigation 3 Form 1 Form 1 Table 1.2 Fields and careers in science Field in science Study Career Biology Study of living things • Doctor/ Nurse • Microbiologist • Botanist • Biotechnologist • Teacher / Lecturer Physics Study of characteristics of matter and energy • Engineer • Physicist • Pilot Chemistry Study of chemical reactions • Pharmacist • Forensic expert • Teacher Meteorology Study of weather and climate change • Meteorologist • Research officer Geology Study of soil and minerals • Geologist • Mineralogist Astronomy Study of stars and planets in the universe • Astronomer • Astronaut Innovation in Technology 1. Technology is defined as the application of scientific knowledge which can benefit us. 2. Developments in the field of technology contributed to the following inventions and discoveries: The invention of trains, ships and aeroplanes enable us to move and transport goods faster and with ease. The Internet and computers make the learning process more conducive and effective. 01 Ranger Science Form 1.indd 3 22/06/2023 2:54 PM
Science Form 1 Chapter 1 Introduction to Scientific Investigation 4 Form 1 Form 1 1.2 Your Science Laboratory Apparatus and Their Functions 1. The science laboratory in school is equipped with enough materials and apparatus for students to conduct experiments with their teacher. 2. Apparatus are special equipments that are used in experiments. 3. The following shows the list of apparatus that are generally used in the laboratory and their functions. (a) Fill / Measure chemical substances Test tube Beaker Boiling tube Conical flask Fill a small quantity of liquid Fill a bigger quantity of chemical substance Fill a small quantity of chemical substance for heating Fill chemicals in liquid state Evaporating dish Measuring cylinder Burette Pipette Fill liquid or solution for evaporating Fill and measure the volume of liquid Measure the volume of liquid to the accuracy of 0.1 cm3 Measure a specific volume of liquid accurately (for example 15.0 cm3 or 30.0 cm3) (b) Transfer / Separate chemical substances Dropper Spatula Filter funnel Transfer a small quantity of liquid Transfer a small quantity of solid substance Used with filter paper to separate sediment from a solution (c) Heat substances Crucible Bunsen burner Round-bottom flask Used to heat solid substances to high temperatures Supply flame for heating Fill chemical substances and liquids for heating 01 Ranger Science Form 1.indd 4 22/06/2023 2:54 PM
Science Form 1 Chapter 1 Introduction to Scientific Investigation 5 Form 1 Form 1 (d) Hold apparatus Tripod stand and wire gauze Retort stand Test tube holder Support the apparatus that is being heated Hold the apparatus during experiments Hold a test tube Symbols of Hazardous Materials in the Laboratory 1. Generally, each chemical substance is placed into a closed bottle or enclosed container. Labels and hazard warning symbols should be pasted on the bottle to warn of the danger of the substance. 2. The following diagrams show a few hazard warning symbols with their meaning, as well as examples of the hazardous substances. Meaning: Corrosive Meaning: Flammable Causes damage to the eyes or skin when touched Examples of substances: Strong acids and alkalis Easily set on fire Examples of substances: Alcohol, petrol, and kerosene Meaning: Irritant Meaning: Toxic or poisonous Causes irritation to the skin, eyes or respiratory system Examples of substances: Ammonia, chlorine and chloroform Causes death if it enters the body Examples of substances: Mercury, benzene, bromine and lead Meaning: Explosive Meaning: Radioactive Produces an explosion if mixed with particular substances Examples of substances: Hydrogen gas, sodium and potassium Releases radiations which can cause cancer Examples of substances: Uranium, radium and plutonium 01 Ranger Science Form 1.indd 5 22/06/2023 2:54 PM
Science Form 1 Chapter 1 Introduction to Scientific Investigation 6 Form 1 Form 1 Safety Rules and Steps in the Laboratory 1. Every student needs to practise safety steps in the laboratory to avoid any accidents from happening. 2. The following are some rules in the laboratory: • Do not enter the laboratory without the teacher’s permission • Do not take any materials or apparatus out of the laboratory • Begin experiments with the teacher’s permission • Wear a lab coat, gloves and proper shoes when carrying out the experiments • Wash apparatus and dispose remaining chemical substances using the correct procedure • Return the apparatus and substances to their correct places after carrying out the experiment • Ensure the cleanliness of the laboratory is maintained at all times • Report any accident or damaged equipment to the teacher immediately 3. The following are actions that are prohibited in the laboratory: • Taking electrical appliances close to the source of water • Taking flammable substances close to the source of fire • Smell or taste a substance directly without the teacher’s permission • Direct the test tube that is being heated towards yourself or your classmate • Play, run or hide in the laboratory • Eat and drink in the laboratory Toxic or poisonous chemicals are usually discarded through the laboratory sink. True or False? Quiz Quiz 01 Ranger Science Form 1.indd 6 22/06/2023 2:54 PM
Science Form 1 Chapter 1 Introduction to Scientific Investigation 7 Form 1 Form 1 1.3 Physical Quantities and Their Units Physical Quantities and S.I. Units 1. Physical quantities are basic quantities and derived quantities. Physical quantities can be calculated and measured. 2. Base quantities consist of length, mass, time, temperature and electric current. These quantities can be measured in the International System of Units (S.I.). Table 1.3 Base quantities and S.I. units Base quantity S.I. unit S.I. unit symbol Length metre m Mass kilogram kg Time second s Temperature Kelvin K Electric current Ampere A 3. The value of a base quantity is obtained through the process of measurement. Example: The length of a pencil can be measured by using a ruler. Prefixes 1. Prefixes are used to represent extremely big or extremely small quantities. Table 1.4 Value of prefixes Prefix Symbol Value Standard form giga G 1 000 000 000 109 mega M 1 000 000 106 kilo k 1 000 103 deci d 0.1 10-1 centi c 0.01 10-2 milli m 0.001 10-3 micro µ 0.000 001 10-6 nano n 0.000 000 001 10-9 Converting Units of Base Quantity Mass kilogram (kg) gram (g) milligram (mg) × 1 000 ÷ 1 000 × 1 000 ÷ 1 000 01 Ranger Science Form 1.indd 7 22/06/2023 2:54 PM
Science Form 1 Chapter 1 Introduction to Scientific Investigation 8 Form 1 Form 1 Example 1 (a) Convert 4.12 kg into g. (d) Convert 2 127 mg into g. (b) Convert 3 500 g into kg. (e) Convert 51 g into mg. (c) Convert 1 200 mg into kg. Solution: (a) 4.12 kg = 4.12 × 1 000 (d) 2 127 mg = 2 127 ÷ 1 000 = 4 120 g = 2.127 g (b) 3 500 g = 3 500 ÷ 1 000 (e) 51 g = 51 × 1 000 = 3.5 kg = 51 000 mg (c) 1 200 mg = 1 200 ÷ 1 000 ÷ 1 000 = 0.0012 kg Length kilometre (km) metre (m) decimetre (dm) centimetre (cm) millimetre (mm) × 1 000 ÷ 1000 × 10 ÷ 10 × 10 ÷ 10 × 10 ÷ 10 Example 2 (a) Convert 450 km into m. (c) Convert 204 dm into m. (b) Convert 120 cm into mm. (d) Convert 15 mm into dm. Solution: (a) 450 km = 450 × 1 000 (c) 204 dm = 204 ÷ 10 = 450 000 m = 20.4 m (b) 120 cm = 120 × 10 (d) 15 mm = 15 ÷ 10 ÷ 10 = 1 200 mm = 0.15 dm Time hour (h) minute (min) second (s) × 60 ÷ 60 × 60 ÷ 60 01 Ranger Science Form 1.indd 8 22/06/2023 2:54 PM
Science Form 1 Chapter 1 Introduction to Scientific Investigation 9 Form 1 Form 1 Example 3 (a) Convert 7 200 seconds into hours. (b) Convert 2.5 hours into seconds. (c) Convert 180 minutes into hours. Solution: (a) 7 200 seconds = 7 200 ÷ 60 ÷ 60 (c) 180 minutes = 180 ÷ 60 = 2 hours = 3 hours (b) 2.5 hours = 2.5 × 60 × 60 = 9 000 seconds Importance of S.I. units in Everyday Life 1. The importance of S.I. units are: (a) Measurement can be understood by everyone around the world. (b) International commercial transactions can be carried out smoothly. (c) Measurement of quantities can be done more accurately. The Use of Measuring Instruments, Accuracy, Consistency, Sensitivity and Errors 1.4 The Use of Right Measuring Instruments Measuring length 1. Length is the distance between two points. 2. Measuring instruments: • Metre rule • Measuring tape 3. Diagram 1.2 shows the correct way to measure length using a metre rule: When you take a reading, the position of your eye needs to be in a straight line directly above the scale to avoid a parallax error. ✓ ✗ ✗ 8 9 10 8.5cm 8.3cm 8.2cm Diagram 1.2 Correct way to read 01 Ranger Science Form 1.indd 9 22/06/2023 2:54 PM
Science Form 1 Chapter 1 Introduction to Scientific Investigation 10 Form 1 Form 1 Measuring mass 1. Mass is the quantity of matter contained within an object. 2. Diagram 1.3 shows two measuring instruments that are suitable for measuring mass. Triple beam balance Lever balance Diagram 1.3 Instruments for measuring mass 3. Diagram 1.4 shows the correct method for taking the reading on a triple beam balance. Total reading of mass = A + B + C = 2.5 g + 200 g + 60 g = 262.5 g C B A Diagram 1.4 Method for taking the reading on a triple beam balance Measuring time 1. Time is the period between two moments. 2. Time can be measured using a stopwatch. 3. Diagram 1.5 shows the correct method for taking the reading on a stopwatch. Reading on the minute scale = 1 minute Reading on the second scale = 6.8 seconds Total reading of recorded time = Reading on the minute scale + reading on the second scale = 1 minute 6.8 seconds Diagram 1.5 Method for taking the reading on a stopwatch Measuring temperature 1. Temperature is the degree of hotness or coldness of an object. 2. The temperature of an object is usually measured in degree Celsius (0C). 3. Temperature is measured using a mercury thermometer. A clinical thermometer is used to measure body temperature. 4. The length of the mercury column inside the thermometer changes according to the change of temperature. 01 Ranger Science Form 1.indd 10 22/06/2023 2:54 PM
Science Form 1 Chapter 1 Introduction to Scientific Investigation 11 Form 1 Form 1 Laboratory thermometer Clinical thermometer Diagram 1.6 Types of thermometer Measuring electric current 1. Electric current is the rate of flow of charge. 2. The value of the electric current can be measured by using an ammeter. Accuracy, Consistency and Sensitivity in Measurement 1. Accuracy, consistency and sensitivity are three of the most important aspects in measurement. Measurement Accuracy The degree of closeness of a measured value to the actual value The ability of the measuring instrument to give the same reading when repeated measurements are taken The ability of the measuring instrument to detect the slightest change in the quantity that is being measured Consistency Sensitivity Diagram 1.8 Definitions of accuracy, consistency and sensitivity 2. Diagram 1.9 shows a demonstration of accuracy and consistency using the results of pistol shots on a target. The centre of the target represents the actual measurement. Not accurate and not precise Accurate and precise Precise but not accurate Actual measurement Diagram 1.9 Accuracy and consistency 3. Measuring instruments with small graduation values are categorised as instruments with high sensitivity. 4. Table 1.5 shows the comparison of sensitivity between three measuring instruments for length. Diagram 1.7 Ammeter and its symbol 01 Ranger Science Form 1.indd 11 22/06/2023 2:54 PM
Science Form 1 Chapter 1 Introduction to Scientific Investigation 12 Form 1 Form 1 Table 1.5 Sensitivity of three measuring instruments for length Measuring instruments Function Smallest reading Metre rule Length, height or width in a straight line up to one metre 0.1 cm/ 1 mm Vernier caliper Inner diameter, outer diameter or depth up to a few centimetres 0.01 cm/ 0.1 mm Micrometer screw gauge Outer diameter or thickness up to a few millimetres 0.001 cm/ 0.01 mm Table 1.6 Instruments Method for taking a reading Jaws Vernier scale Main scale Vernier caliper The ‘0’ mark on the vernier scale is at 3.0 cm. The 9th mark on the vernier scale lines up with the main scale. Reading = 3.0 cm + 0.09 cm = 3.09 cm Spindle Vernier scale Main scale Micrometer screw gauge 0 5 20 15 10 5 Main scale Vernier scale The biggest value seen on the main scale is 5.50 mm The 13th value on the vernier scale lines up with the main scale. Reading = 5.50 mm + 0.13 mm = 5.63 mm Digital measuring instruments 1. Using digital measuring instruments which are more sensitive is one way to increase the accuracy of the reading. 2. A digital vernier caliper decreases parallax error which results from the observer’s error. This caliper can give a reading as small as 0.01 mm. 3. A digital micrometer screw gauge can give a reading as small as 0.001 mm. 4. One of the advantages of a digital thermometer is its ability to give temperature reading within a brief period of time. 5. A digital scale is the scale usually found in the laboratory. This scale can give a reading as small as 0.01 g. 01 Ranger Science Form 1.indd 12 22/06/2023 2:54 PM
Science Form 1 Chapter 1 Introduction to Scientific Investigation 13 Form 1 Form 1 Systematic Error and Random Error 1. Diagram 1.10 shows the comparison between systematic error and random error. Definition of error The difference between a reading value and its true value Systematic error Scale calibration error of a measuring instrument Example: Zero error – obtaining a reading that is not zero when the reading value is actually zero The actual reading is obtained when the zero error is taken into account. Actual reading = Reading of the scale – zero error Changes in the environment or errors in using the measuring instruments Example: Parallax error is caused by the observer’s error while taking the reading Can be minimised by taking an average reading from repeated experiment readings Random error Diagram 1.10 Comparison between systematic error and random error Reducing zero error 1. Zero error of a voltmeter scale can be corrected by turning the screw at the base of the needle. V Voltmeter Screwdriver Diagram 1.11 Method of preventing zero error in a voltmeter 01 Ranger Science Form 1.indd 13 22/06/2023 2:54 PM
Science Form 1 Chapter 1 Introduction to Scientific Investigation 14 Form 1 Form 1 Reducing parallax error 1. Parallax error can be prevented when the observer places his/her eye at the correct position. 2. The correct way to take the reading of the volume of liquid in a measuring cylinder: Meniscus curves downward (Example: Water) Meniscus curves upward (Example: Mercury) ✓ ✗ ✓ Making an Estimation 1. The following activity shows some ways to estimate a quantity that is too large or too small compared to the range of the measuring instruments and when there is no suitable measuring instruments. (a) Estimating the length of a pencil Method: Arrange a few paper clips along the length of the pencil. Result: Estimated measurement: Pencil length = 5 paper clips (b) Estimating the thickness of a coin Method: Arrange 15 pieces of 20-cent coins as shown in the diagram. Then, measure the height. Result: The thickness of one coin = 3.0 cm 15 = 0.2 cm (c) Estimating the thickness of a wire Method: Coil the wire tightly around an iron rod measuring 3.0 cm. Result: Thickness of wire = Length of wire Number of coils = 3.0 cm 13 = 0.23 cm 4 3 2 cm 15 coins 1 0 13 coils Thickness of wire 01 Ranger Science Form 1.indd 14 22/06/2023 2:54 PM
Science Form 1 Chapter 1 Introduction to Scientific Investigation 15 Form 1 Form 1 (d) Estimating the area of an irregular shape Method: 1. Trace the outline of the leaf on a sheet of graph paper with squares measuring 1 cm x 1 cm each. 2. Only full squares, half-full squares or more than half full squares are counted and marked ‘✓’. Result: Number of ‘✓’ marks = Area of the leaf shape = 23 cm2 1.5 Density Density of a Substance 1. Density is the mass per unit of volume of a substance. 2. The S.I. unit for density is kilogram per cubic metre (kg/m3 or kg m-3). 3. The density of an object determines the buoyancy of the object in fluid. 4. Objects that are denser will sink to the bottom of the fluid while objects that are less dense will float on the surface of the fluid. Alcohol (0.8 g cm–3) Cork (0.24 g cm–3) Wood (0.9 g cm–3) Water (1.0 g cm–3) Lead (11.3 g cm–3) Mercury (13.6 g cm–3) Denser Less dense Diagram 1.12 Position of substances according to density value 5. Table 1.7 lists substances and their respective density values. Table 1.7 Density of different substances State of matter Name of substance Density (g cm–3) Solid Cork 0.24 Wood 0.90 Glass 2.60 Iron 7.90 Silver 10.50 Lead 11.30 ✓ ✓ ✓ ✓ ✓ ✓ ✓✓ ✓ ✓✓ ✓ ✓ ✓ ✓✓ ✓ ✓ ✓ ✓ ✓✓ ✓ 1 cm 1 cm Mercury will ______ in alcohol. Quiz Quiz 01 Ranger Science Form 1.indd 15 22/06/2023 2:54 PM
Science Form 1 Chapter 1 Introduction to Scientific Investigation 16 Form 1 Form 1 Liquid Petrol 0.80 Alcohol 0.80 Water 1.00 Mercury 13.60 Gas Hydrogen 0.00009 Air 0.00122 Oxygen 0.00133 Calculating Density by Using a Formula Density (g cm–3) = Mass, m Volume, V INFO CORNER Easy method to remember the formula for density: ρ = Density m = Mass V = Volume m ρ × V m D × V ρ × V m M ρ × V ρ = m V V = m ρ m = ρ × V Example 1 The mass of a 24.3 cm3 ping pong ball is 2.7 g. Calculate the density of the ping pong ball. Solution: Density = 2.7 g 24.3 cm3 = 0.11 g cm–3 m D × V Example 2 Determine the volume for 250 g of a substance with a density of 0.32 g cm-3. Solution: Volume = 250 g 0.32 g cm-3 = 781.25 cm3 ρ × V m 01 Ranger Science Form 1.indd 16 22/06/2023 2:54 PM
Science Form 1 Chapter 1 Introduction to Scientific Investigation 17 Form 1 Form 1 Water Displacement Method 1. The water displacement method is used to determine the density of an irregular shaped object. 2. Diagram 1.13 shows the steps to determine the density of a stone using the water displacement method: OFF ON g 16.00 Weight the stone to get its mass value. • Mass of the stone = 16 g 0 10 20 30 40 50 60 70 80 90 100 ml Fill the measuring cylinder with water. • Initial reading of the volume of water = 55 cm3 (a) (c) (b) Immerse the stone fully in the water inside the measuring cylinder. Record: • Final reading of the volume of water = 78 cm3 • Volume of the stone = Rise in water level = 78 cm3 – 55 cm3 = 23 cm3 Therefore, density = 16 g 23 cm3 = 0.70 g cm–3 0 10 20 30 40 50 60 70 80 90 100 ml Diagram 1.13 Water displacement method Application of Concept of Density 1. Humans who understand the density of objects apply it in various aspects of everyday life. Table 1.8 Application of the concept of density Application Explanation Lifting logs Rivers are used as a means for transporting logs because the logs are less dense than the water. Submarine • A submarine sinks when water fills the ballast tank because the submarine becomes denser than the seawater. • The submarine floats when the ballast tank is emptied because the submarine becomes less dense than the seawater. Hot air balloon The balloon floats in the air because the density of hot air in the balloon is lower than the density of air outside the balloon. Buoys, life jackets These objects are filled with air so they can float on the surface of the water. (c) 01 Ranger Science Form 1.indd 17 22/06/2023 2:55 PM
Science Form 1 Chapter 1 Introduction to Scientific Investigation 18 Form 1 Form 1 1.6 Steps in a Scientific Investigation 1. There are 12 science process skills that must be practised by all students, namely: • Observing • Classifying • Measuring and using numbers • Making inferences • Predicting • Communicating • Using the time-space relationships • Interpreting data • Defining operationally • Controlling variables • Making a hypothesis • Experimenting 2. A scientific investigation is carried out to obtain data or results that can prove the validity of a hypothesis, theory or law. 3. The scientific investigation involves the following steps: (1) Make an observation Using the senses to carry out observations of a situation/ event/ phenomenon. (2) Identify a problem Making a problem statement based on observation. (3) Construct a hypothesis • Making a reasonable guess in suggesting an explanation for the problem statement. • The hypothesis connects the manipulated variable with the responding variable. (4) Control variables • Variables are factors that influence the results of the experiment. • Three variables: ✓ Manipulated variable (the factor that is changed systematically throughout the experiment ✓ Responding variable (the factor that changes throughout the experiment) ✓ Constant variable (the factor that is kept constant/unchanged throughout the experiment) (5) Plan an experiment • Preparing the materials and apparatus that are required to carry out the experiment. • Determining the correct way to monitor the variables and collect data/results. 01 Ranger Science Form 1.indd 18 22/06/2023 2:55 PM
Science Form 1 Chapter 1 Introduction to Scientific Investigation 19 Form 1 Form 1 (6) Conduct the experiment • Conduct the experiment as in plan. • Precautions must be practised at all time. (7) Collect data • Data/results need to be collected accurately and truthfully. • The data can be recorded in the form of a table. (8) Analyse and interpret data • The data that is collected is analysed by relating the manipulated variable with the responding variable. (9) Make a conclusion • Based on the data obtained, the hypothesis may be accepted or rejected. • If the hypothesis is rejected, a new hypothesis is formed and the experiment is carried out again. (10) Write a report • A complete report includes the following information: ✓ Problem statement ✓ Procedure ✓ Hypothesis ✓ Observation/Results ✓ Aim ✓ Analysis and interpretation of data ✓ Variables ✓ Conclusion ✓ Materials and apparatus Scientific Attitudes and Values in Carrying Out Scientific Investigations 1.7 1. Scientific research should bring benefits to humans. 2. This can only be achieved if the following attitudes and positive values are practised when carrying out scientific research: • Values the contributions of science and technology • Systematic, confident and ethical • Responsible for the safety of yourself, people around you and the environment • Truthful and accurate in recording and validating data • Hardworking, cooperative and honouring • Open-minded • Values the balance of nature 01 Ranger Science Form 1.indd 19 22/06/2023 2:55 PM
Science Form 2 Chapter 1 Biodiversity Form 2 Form 2 120 Importance of Biodiversity Classifcation of Animals Importance of biodiversity Source of food Generates economy Source of medicine Education Balance in nature Classification of animals Invertebrate Vertebrate With legs Without legs Three pairs of legs More than three pairs of legs Segmented body Non-segmented body Fish Amphibians Reptiles Birds Mammals CHAPTER BIODIVERSITY Form 2 1 i-THINK Gallery Theme 1: Maintenance and Continuity of Life 01 Ranger Science Form 2.indd 120 22/06/2023 4:11 PM
Science Form 2 Chapter 1 Biodiversity Form 2 Form 2 121 Biodiversity 1. Biodiversity is the diversity of living organisms including animals, plants and microorganisms. 2. The existence of biodiversity is the result of the diversity of habitats and climates. 3. The habitat is the natural environment where plants and animals live and reproduce. Every organism has different characteristics and therefore, they need a habitat that can provide food, shelter and temperature that is suitable for life. 4. The importances of biodiversity: • Provide sources of food for humans and other living organisms • Maintain balance in nature in the environment • Generate economy, for example recreational parks, tourism, biotechnology, medicine and industrial raw materials • Sources of medicine • Education 5. Malaysia’s status as one of the twelve mega biodiversity countries should be preserved for the future generations. Effective Biodiversity Management 1. Human activities which are carried out indiscriminately can destroy biodiversity. Some of the human activities are as shown below: Illegal hunting Deforestation River pollution as a result of agriculture and industrial activities Diagram 1.1 Human activities 1. Endemic species are species that can be found within a restricted habitat in a specific location. 2. Many species are endemic and threatened, among them are the Sumatran tiger, orangutan, the Sumatran rhinoceros and several other species that have become extinct as a result of human activities. 1.1 Diversity of Organisms 01 Ranger Science Form 2.indd 121 22/06/2023 4:11 PM
Science Form 2 Chapter 1 Biodiversity Form 2 Form 2 122 Creating forest reserves, Ramsar sites, rehabilitation centres, national parks, botanical gardens and wildlife sanctuaries. Conducting awareness campaigns at all levels Replanting after deforestation Enforcement of laws Method to maintain and conserve biodiversity Diagram 1.2 1.2 Classification of Organisms Classification of Animals 1. Animals can be classified into two main groups. They are invertebrates and vertebrates. Invertebrates 1. Invertebrate animals are animals without backbones. Invertebrates without legs Without segmented body Diagram 1.3 Invertebrates without legs Tapeworm Leech Snail Sea anemone Earthworm With segmented body Starfish Invertebrates with legs Three pairs of legs More than three pairs of legs Diagram 1.4 Invertebrates with legs Cockroach Prawn Grasshopper Scorpion Ant Centipede 01 Ranger Science Form 2.indd 122 22/06/2023 4:11 PM
Science Form 2 Chapter 1 Biodiversity Form 2 Form 2 123 Vertebrates 1. Vertebrates are animals with backbones. Vertebrates are divided into five groups according to their specific features. Mammals • Homeothermic (Animals that has constant body temperature which is not influenced by surrounding temperature) • Breathes through its lungs • Gives birth and nurses its young • Body covered with hair • Internal fertilisation Reptiles Birds • Poikilothermic • Breathes through lungs • Produces eggs with shells • Body covered with scales and hard skin • Internal fertilisation Hard scales Snake • Homeothermic • Breathes through lungs • Produces eggs with shells • Body covered with feathers • Has wings and a beak • Internal fertilisation Feathers Birds Fish Amphibian • Poikilothermic (Animals that has body temperatures changes depending on the temperatures of their surroundings) • Breathes through gills • Lays eggs • Body covered with scales • External fertilisation Fin Goldfish • Poikilothermic • Lives in water and on land • Breathes through gills (young) and lungs and moist skin (adults) • Produces slimy eggs without shells • Body covered with moist skin scales • External fertilisation Moist skin Frog Diagram 1.5 Vertebrates Fur Horse 01 Ranger Science Form 2.indd 123 22/06/2023 4:11 PM
Science Form 2 Chapter 1 Biodiversity Form 2 Form 2 124 Classification of Plants 1. Plants are classified into flowering plants and non-flowering plants. 2. Flowering plants reproduce through seeds. Non-flowering plants reproduce by producing spores or seeds inside cones. Non-flowering plants Non-flowering plants Moss Fern Conifer • Reproduces by producing spores • Non-vascular • Reproduces by producing spores • Vascular • Reproduces by producing cones • Vascular Diagram 1.6 Non-flowering plants Flowering plants 1. Flowering plants are divided into two groups which are monocotyledon plants and dicotyledon. Monocotyledon Dicotyledon Parallel vein Fibrous root Non-woody stem Network-like vein Woody stem Tap root Diagram 1.7 Flowering plants One cotyledon Two cotyledons 01 Ranger Science Form 2.indd 124 22/06/2023 4:11 PM
Science Form 2 Chapter 1 Biodiversity Form 2 Form 2 125 A grasshopper and a spider can be separated into two different groups based on the number of their ______. Quiz Quiz 2. Monocotyledon have seeds made up of one cotyledon while dicotyledon have seeds made up of two cotyledons. 3. Examples of monocotyledon: Sugarcane, maize, paddy and coconut. 4. Examples of dicotyledon: Rambutan tree, rose tree and balsam tree. Constructing a Dichotomous Key 1. A dichotomous key is a method used to identify and classify organisms systematically. 2. A dichotomous key is produced from several series of couplets where each couplet is made up of two statements on the characteristics of an organism or a particular group of organisms. Example of a dichotomous key Grasshopper Crocodile Cat Earthworm Frog Dichotomous key 1. (a) With backbone................................................................................................ Go to number 2 (b) Without backbone ....................................................................................... Go to number 3 2. (a) Lay eggs ......................................................................................................... Go to number 4 (b) Gives birth ....................................................................................................... Cat 3. (a) With legs ......................................................................................................... Grasshopper (b) Without legs ................................................................................................. Earthworm 4. (a) Has moist skin................................................................................................. Frog (b) Does not have moist skin ............................................................................ Crocodile Diagram 1.8 Dichotomous key 01 Ranger Science Form 2.indd 125 22/06/2023 4:11 PM
Science Form 3 Chapter 1 Stimuli and Responses Form 3 Form 3 226 Human Sensory Organs Responses of Plants Human sensory organs Tongue Ears Skin Nose Eyes Responses of plants Tropism Nastic movement Phototropism Hydrotropism Geotropism Thigmotropism i-THINK Gallery CHAPTER STIMULI AND RESPONSES Form 3 1 Theme 1: Maintenance and Continuity of Life 01 Ranger Science Form 3.indd 226 22/06/2023 3:12 PM
Science Form 3 Chapter 1 Stimuli and Responses Form 3 Form 3 227 What are the two main parts of the nervous system? Quiz Quiz 1. The human nervous system is made up of the brain, the spinal cord and the peripheral nerves. Spinal nerves Peripheral nervous system Central nervous system Brain Cranial nerves Spinal cord The function of the human nervous system: • Detects stimuli • Sends information in the form of impulses • Interprets impulses • Produces appropriate responses Diagram 1.1 Human nervous system Voluntary and Involuntary Actions Voluntary action 1. Voluntary actions are conscious actions that are carried out voluntarily. 2. Examples of voluntary actions are walking, reading, running, eating and drinking. 3. All voluntary actions are controlled by the brain. Stimuli Affector (receptor) Effector (muscle or gland) Reponse Diagram 1.2 Pathway of impulse in voluntary action Involuntary action 1. An involuntary action takes place spontaneously and unconsciously or without prior thought. 2. Involuntary actions are divided into two groups: (a) Actions controlled by the medulla oblongata like the heartbeat, breathing and peristalsis. (b) Reflex actions involve the spinal cord. For example, removing the hand when it touches a hot kettle or withdrawing the leg when one steps on a nail. 1.1 Human Nervous System 01 Ranger Science Form 3.indd 227 22/06/2023 3:13 PM
Science Form 3 Chapter 1 Stimuli and Responses Form 3 Form 3 228 Medulla oblongata/ Spinal cord Stimuli Response Affector Effector Diagram 1.3 Pathway of impulse in involuntary action Importance of the Network of Human Nervous System in Daily Life 1. The human nervous system functions to control and coordinate organs and parts of the body so that they can function efficiently in carrying out our daily activities. 2. Our nervous system functions to protect our body from danger, for example the muscles will react if our body gets in touch with heat or sharp objects. 3. Injuries to the central nervous part, medulla oblongata will affect actions such as heartbeat and breathing. 4. A damaged nervous system would cause a temporary or a permanent paralysis in a person. In more serious cases, the person would most probably depend on machines for breathing. 1.2 Stimuli and Responses in Humans 1. Diagram 1.4 shows five sensory organs of human, namely eyes, ears, nose, tongue and skin. Diagram 1.4 Human sensory organs INFO CORNER Excessive consumption of alcohols and drugs can affect the central nervous system by delaying the transmision of impulses. 01 Ranger Science Form 3.indd 228 22/06/2023 3:13 PM
Science Form 3 Chapter 1 Stimuli and Responses Form 3 Form 3 229 Eyes 1. The eye is the sensory organ of sight. Sclera Maintains the shape and protects the eye. Lens Focuses light on the retina. Ciliary muscles Control the thickness of the lens. Suspensory ligament Hold the lens of the eye. Cornea Refracts and focuses light on the retina. Iris Controls the size of the pupils. Pupil Controls the amount of light that enters the eye. Aqueous humour Maintains the shape of the eyeball and focuses light inwards. Conjunctiva Protects the front part of the sclera. Vitreous humour Maintains the shape of eyeball and focuses light on the retina. Blind spot Not sensitive to light because there are no photoreceptors. Optic nerve Carry nerve impulses from the retina to the brain. Yellow spot Very sensitive to light because there are a lot of photoreceptors. Choroid Prevents reflection inside the eye. Supplies oxygen and nutrients to the eye. Retina Contains photoreceptors that detect light and produce nerve impulses. Diagram 1.5 Structure of the human eye and its functions 01 Ranger Science Form 3.indd 229 22/06/2023 3:13 PM
Science Form 3 Chapter 1 Stimuli and Responses Form 3 Form 3 230 2. The retina has two types of photoreceptors, rods and cones. (a) The rod cell is sensitive towards different intensity of light including faint light. This cell is not sensitive to colours. (b) The cone cell is sensitive towards colours in a bright environment. There are three types of cone cells, with each is sensitive to red, green and blue lights. Retina Rod cell Cone cell Optic nerve Ciliary muscle Iris Lens Pupil Cornea Diagram 1.6 Photoreceptor Ear 1. The ear is a sensory organ that is able to detect sound waves. Outer ear Middle ear Inner ear Diagram 1.7 Structure of the human ear Table 1.1 Structure of ear and its functions Ear structure Function Earlobe Collects sound waves and directs them into the ear canal. Ear canal Directs the sound waves to the eardrum. Eardrum Vibrates at the same frequency as the sound waves and transfers the vibration to the ossicles. Ossicles Strengthens the vibrations and transfers them to the oval window. Oval window Transfers the sound vibrations from the ossicles to the cochlea. Eustachian tube Balances the air pressure on both sides of the eardrum. Cochlea Detects and converts the sound waves into nerve impulses. Semicircular canal Controls the body balance. Auditory nerve Sends nerve impulses from the cochlea to the brain to be interpreted. Oval window 01 Ranger Science Form 3.indd 230 22/06/2023 3:13 PM
Science Form 3 Chapter 1 Stimuli and Responses Form 3 Form 3 231 Nose 1. Diagram 1.8 shows the structure of a human nose that detects smell. Diagram 1.8 Structure of the human nose 2. Nose is used to smell. Smell is a chemical substance that present in the air. There is a sensory cell in the upper part of the nasal cavity. The dissolved chemicals stimulate the sensory cell to produce impulses. The nerve impulses are then sent to the brain to be interpreted. Air that contains chemical substances dissolve in mucus. Diagram 1.9 Mechanisme of sense of smell Tongue 1. The tongue is the sensory organ of taste. On the upper surface of the tongue, there are small spots known as the papillae covered with hundreds of taste buds. 2. Every taste bud has a taste receptor that can detect five types of basic of taste which are sweet, bitter, salty, sour and umami. Diagram 10.1 Structure of the human tongue 01 Ranger Science Form 3.indd 231 22/06/2023 3:13 PM
Science Form 3 Chapter 1 Stimuli and Responses Form 3 Form 3 232 These chemicals would then seep into the taste buds and stimulate the receptor and then produce nerve impulses. The nerve impulses are then sent to the brain to be interpreted. Chemical substances in the food dissolve in saliva when the food is being chewed. Diagram 1.11 Mechanism of taste Skin 1. Skin is the largest sensory organ on the body. 2. Skin is made up of three layers; epidermis, dermis and layer of fat. 3. Skin has five types of receptors to detect touch, pain, cold, heat and pressure. Diagram 1.12 Structure of the human skin Mechanism of Hearing Diagram 1.13 Mechanism of hearing in human 01 Ranger Science Form 3.indd 232 22/06/2023 3:13 PM
Science Form 3 Chapter 1 Stimuli and Responses Form 3 Form 3 233 Mechanism of Sight Light rays from the object enter the eye through the corner, aqueous humour, lens and straight to vitreous humour and the light ray is focussed on the retina. Photoreceptors are stimulated by the light ray to produce nerve impulses which are sent to the brain by the optic nerve. The brain interpretes the nerve impulses. Image formed is smaller and upright. Light from the object Aqueous humour Vitreous humour Retina Nerve to Lens the brain Cornea Diagram 1.14 Mechanism of sight in human The Relationship Between Human Sensory Organs and Sensitivity towards Various Combinations of Stimuli Sensitivity of the Skin on Different Parts of the Body towards Stimuli 1. Sensitivity of skin towards stimuli depends on: (a) Number of receptors - the higher the number of receptors, the higher the sensitivity of the skin. (b) Thickness of epidermis - the thinner the epidermis, the higher the sensitivity of the skin. The doctor injects the patient on the arm or the buttocks because the skin there is less sensitive. The blind use the tips of their fingers to read Braille because the fingertips are highly sensitive. Diagram 1.15 Examples of sensitivity of skin on different parts of the body 01 Ranger Science Form 3.indd 233 22/06/2023 3:13 PM
Science Form 3 Chapter 1 Stimuli and Responses Form 3 Form 3 234 Sensitivity of the tongue towards different taste stimuli 1. All areas on the tongue are sensitive to five tastes which are sweet, salty, sour, bitter and umami tastes. 2. However, different areas of the tongue have a particular sensitivity to taste. Diagram 1.16 Different areas of the tongue are sensitive to specific tastes Bitter Sweet Umami Salty Sour Sour Salty INFO CORNER Umami is a savoury food taste. For example, the taste of boiled meat water, butter and monosodium glutamate (MSG). Combination of the sense of taste and the sense of smell 1. The smell sense plays an important role when a person is tasting food. The taste and the smell senses have a strong bond in food tasting. 2. When a person has a cold, he cannot taste the food properly because the chemical substances in the food do not reach the sensory cells in the nose as a result of excessive mucus. 3. The same thing happens when we close our nose, food becomes less appetising when there is no assistance from the smell sense. Limitations of Sight 1. The limitation of the sense of sight is the ability of the eyes to see objects. Human eyes cannot see objects that are very tiny or objects that are too far away. 2. Optical illusions and blind spots are other examples of the limitation of the sense of sight. 3. An optical illusion occurs when the object that is being viewed is different from the actual situation. Look at the circle in the centre. Which circle seems bigger? Can you see the black spots that appear on the lines and then disappear? Diagram 1.18 Optical illusions Diagram 1.17 01 Ranger Science Form 3.indd 234 22/06/2023 3:13 PM
Science Form 3 Chapter 1 Stimuli and Responses Form 3 Form 3 235 4. The blind spot happens when the image that falls on the blind spot cannot be seen. In some situations, blind spots cause danger especially when driving. • Hold the book with your right hand. • Close your left eye. Look at the cross with your right eye and slowly move the book towards your eye. • At a certain distance from the eye, the cross would disappear from your view. X O Microscope Ultrasound machine X-ray machine Telescope Diagram 1.19 Examples of devices to overcome the limitation of the sense of sight Defects of Sight and Ways to Correct Them Table 1.1 Defects of sight and ways to correct them Defect of sight Ways to correct them Short-sightedness • An individual who suffers from short-sightedness cannot see objects that are far away clearly. • Image is focussed in front of the retina. • Cause: The lens is too thick or the eyeball is too long. • Correction: By using concave lens A concave lens is used for the image to fall on the retina Long-sightedness • An individual who suffers from long-sightedness cannot see objects that are near to him/ her clearly. • The image is focussed behind the retina. • Cause: The lens is too thin or the eyeball is too short. • Correction: By using convex lens A convex lens is used for the image to fall on the retina 01 Ranger Science Form 3.indd 235 22/06/2023 3:13 PM
Science Form 3 Chapter 1 Stimuli and Responses Form 3 Form 3 236 Astigmatism Sight defect causes a person to see one part of an object clearer than the other parts. This is caused by an irregular curve on the surface of the cornea. Image (a) is the actual image while image (b) is an example of the image as seen by the individual who suffers from astigmatism. Astigmatism can be corrected by using a cylindrical lens. Cylindrical lens Limitations of Hearing 1. The limitation on the hearing sense is the limitation on the ability of our ears to hear. Humans can hear sounds in the frequency range of 20 Hz to 20 000 Hz. 2. The following shows the various devices invented to overcome the limitations on the hearing sense. Stethoscope is used to hear the heartbeat An amplifier is used to amplify the sound A hearing aid Diagram 1.20 Hearing aid devices 3. Hearing defects happen when a person is unable to hear sounds. This is due to ear damage caused by infections, injury, exposure to prolonged loud sound or aging factor. 4. Damage to the outer ear and middle ear can be corrected through medication or surgery. 5. However, damage to the inner part of ear is more difficult to correct. Cochlea implants can be used to correct a damaged cochlea but the damage to the auditory nerve cannot be corrected neither through medication nor surgery. 01 Ranger Science Form 3.indd 236 22/06/2023 3:13 PM
Science Form 3 Chapter 1 Stimuli and Responses Form 3 Form 3 237 The Five Senses - a Gift 1. God has blessed us with a complete set of sensory organs. We should be grateful for this blessing and maintain a healthy lifestyle and keep away from activities that would affect our sensory organs. Diagram 1.21 Activities that can affect our sensory organs 2. An individual who is exposed to high risk professions such as the firefighter, have to wear safety gear/personal protective equipment (PPE) to protect their bodies from danger. Workers who are exposed to loud noises such as at the airport have to use earmuffs or earplugs. 1.3 Stimuli and Responses in Plants 1. Plants can detect stimuli such as light, water, gravity and touch. Responses of plants Tropism Nastic movement Diagram 1.12 Responses of plant towards stimuli Tropism 1. Tropism is the directional response of the plant towards stimuli from a particular directions. 2. The part of the plant that grows towards the stimuli is known as positive tropism while the part of the plant that grows away from the stimuli is known as negative tropism. 3. The following experiment is carried out to study the responses of the plants towards various stimuli. 01 Ranger Science Form 3.indd 237 22/06/2023 3:13 PM
Science Form 3 Chapter 1 Stimuli and Responses Form 3 Form 3 238 (A) Response of plants to light (Phototropism) P Box Moist cotton wool Seedlings Light Light Light Q R Results: The shoots grow in the direction of the hole. Discussion: • The shoots of the plants grow towards light. The shoots show positive phototropism. • The roots show negative phototropism. (B) Response of plants to gravity (Geotropism) Results: The roots grow towards gravity while the shoots grow in the opposite direction. Discussion: • The seedlings are kept in the dark cupboard to ensure its response is not influenced by light. • The roots grow downwards. The root shows positive geotropism. • The shoots grow upwards away from the gravity. The shoots show negative geotropism. (C) Response of plants to water (Hydrotropism) Moist cotton wool Seedling with straight roots Wire gauze Anhydrous calcium chloride Water A B Results: The root grows towards the direction of the water in both beakers A and B. Discussion: • The root grows towards the direction of the water. The roots show positive hydrotropism. • The function of the anhydrous calcium chloride is to absorb water. Petri dish Seedling with straight root and shoot Moist cotton wool Clay 01 Ranger Science Form 3.indd 238 22/06/2023 3:13 PM
Science Form 3 Chapter 1 Stimuli and Responses Form 3 Form 3 239 Tropisms Phototropism Thigmotropism • Phototropism is the plants response towards light. • Positive phototropism ensures that the tips and the leaves grow towards light so that the plants get enough sunlight to carry out photosynthesis. • Hydrotropism is the plants response towards water. • The roots show positive hydrotropism as they grow towards the direction of water. • This response enables the plants to get sufficient water and dissolved minerals. • Geotropism is the response of plants towards gravity. • Positive geotropism enables the plants’ roots to grow deeper into the soil with a strong grip and obtain water and minerals. • The shoots of the plants show negative geotropism. • Thigmotropism is the plant’s response towards touch. • The plants have tendrils or twining stems that creep on any objects or other plants that touch it. • This response helps the plant to get sunlight and support. Hydrotropism Geotropism Diagram 1.23 Types of tropisms Nastic movement 1. Nastic movements are responses towards stimuli such as touch which comes from various directions. 2. Nastic movements happen faster than tropism. Nastic movements function as a defence for the plant against danger. INFO CORNER Examples of nastic movement Photonasty – Movement towards light stimuli Thermonasty – Response towards temperature stimuli Seismonasty – Response towards touch stimuli 01 Ranger Science Form 3.indd 239 22/06/2023 3:13 PM
Science Form 3 Chapter 1 Stimuli and Responses Form 3 Form 3 240 Diagram 1.24 Mimosa pudica responds by folding its leaves inwards when touched Importance of Responses to Stimuli in Animals 1.4 Stereoscopic and monocular visions Table 1.3 Differences between stereoscopic vision and monocular vision Stereoscopic vision Monocular vision Animals have a pair of eyes in front of their head. Animal’s eyes located on the sides of their head. Vision field is narrow. A wide vision field. The vision fields overlap giving a threedimensional view. The vision fields do not overlap or only a slight overlap. Distance, size and depth of object can be estimated more accurately as a result of one’s ability to view an image three-dimensionally. Cannot estimate distance, size and objects accurately because two dimensional images form in this vision field. The advantage of this view: Helps animals in hunting because of the ability to estimate distance accurately. The advantages of this vision: A wide vision field helps the animals to detect their enemies which come from any direction. Humans and most predators like the tiger and the lion. Most preys like the rabbit, mouse and deer. Pertindihan besar Large overlap Pertindihan kecil Small overlap 01 Ranger Science Form 3.indd 240 22/06/2023 3:13 PM
Science Form 3 Chapter 1 Stimuli and Responses Form 3 Form 3 241 Stereophonic hearing 1. Stereophonic hearing is hearing using both ears. 2. The advantages of stereophonic hearing: • Enables humans to determine the direction of the sound accurately. • Enables predators to determine the location of their prey accurately. • Enables the prey to escape from the predator the moment it knows the location of the predator. Hearing Frequencies of Animals 1. Different animals have the abilities to hear different frequencies of sound: Table 1.4 Animals and their hearing frequency range Animal Hearing frequency range Bat 2 000 – 110 000 Hz Dog 67 – 45 000 Hz Dolphin 40 – 10 000 Hz Rat 200 – 80 000 Hz Sea lion 450 – 50 000 Hz Cat 45 – 64 000 Hz Elephant 16 – 12 000 Hz Sensory Organs Ensure the Survival of Animals on Earth 1. Animals have their own responses towards stimuli. These responses ensure the continuity of animals on Earth. 2. Animals like eel responds by producing electricity to defend itself besides hunting for its prey. 3. Female beetle (Melolontha) secretes a strong pheromone which is detected by the male beetle’s antennae for breeding. 4. A small type of spider (Lyssomanes viridis) has complex eyes, more than a pair of eyes which enable it to see very clearly. 5. The fish has the lateral line; the sensory organ of which is sensitive towards vibration, pressure and sounds. INFO CORNER Scientists are researching actively on the habits of several types of animals that able to predict an earthquake. Animals like cat, snake, frog, dog and birds are found to have abandoned their habitats before the tremors of the earthquake take place. From Table 1.4, human hearing frequency range is between which two animals? Quiz Quiz 01 Ranger Science Form 3.indd 241 22/06/2023 3:13 PM
• Bahasa Melayu • English • Matematik • Mathematics • Sains ✓Science • Sejarah • Geografi • Reka Bentuk dan Teknologi • Pendidikan Islam i-THINK Gallery Concise Notes UASA Model Papers & Answers Form 1/2/3 RANGER Form 1.2.3 series is published specifically to fulfil the UASA (Ujian Akhir Sesi Akademik) format. The content of this series is comprehensive and incorporates all the latest syllabus. This book can serve as a quick revision for students to increase their understanding prior to their preparation for UASA assessment. Info & Video QR Code QR Code Purchase eBook here! W.M: RM19.95 / E.M: RM19.95 KC117944 ISBN: 978-629-470-103-8 KC117944 Science Form 1.2.3 KSSM