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Chapter 3 – Sound

The following Topics and Sub-Topics are covered in this chapter and are available on MSVgo:


Sound, like electricity, heat, and light, is a source of energy. Let’s explore the various sources of sounds like a whistle. A bell makes a constant ringing noise when hit. Place the finger on the bell when you’ve rattled it, rather than simply reacting to it. Is it vibrating towards you? The trick to the tone is this. Guitars and percussion show that off even further. When you pluck it, you can feel the wires vibrating. The echo ceases until the bell or the instrument stops vibrating. 

Vibration is the to-and-fro movement of an object. Vibrations can be seen all over the place. 

Vibrating objects create sound. Some vibrations can be seen, although others aren’t visible. When you pull and then loosen a stretched rubber band, it travels back and forth along the central axis, creating a sound in the process. Sound flows through a channel by contracting and widening segments of the medium as it goes through.

A portion of a wave is mirrored, and a portion of the wave is sent over the barrier as it hits the boundary between two mediums. The difference between the two media determines the sum of contemplation. 

The reflection of sound waves off the surfaces will create either an echo or a reverberation. A reverberation is typical in a small space with 17 meters or less in height, width, and volume. 

Echoes are triggered by sound waves bouncing off of each other. Reverberations are not the same as echoes. When a reflected sound wave arrives at the ear longer than 0.1 seconds after the main sound wave, it is called an echo. If the time between the arrivals of the two sound waves is longer than 0.1 second, the first sound’s impression would have disappeared. In this situation, the second sound wave would be heard as a separate sound rather than a continuation of the previous. Instead of reverberation, there would be an echo.

  • This is a vibration effect dependent on the sound wave’s intensity. The sound is said to be noisy if the amplitude of the sound wave is high. 
  • That is equal to the square of the vibration’s amplitude. The loudness of the echo will be quadrupled if the amplitude of the sound wave is multiplied. 
  • It is measured in decibels (dB). 
  • Human ears interpret noises over 80 decibels as noise. 

Its relationship to its amplitude defines a sound wave’s loudness. A sound wave’s loudness is defined by its relationship to its amplitude; all waves have a definite amplitude. For example, in a calm ocean, a wave’s height would be less than 1 foot, while good surfing waves will be 10 feet or more in amplitude. The amplitude will exceed 40 to 50 feet during a storm.

  • This is determined by the magnitude of the waves’ vibrations. 
  • The tone is shrill and has a loud pitch if the level of vibration is greater. On the other side, if a sound is said to have a lower pitch, it means that it vibrates at a lower level. 
  • A bird creates a high-pitched sound, while a lion’s scream is low-pitched. 
  • The pitch of a woman’s voice is greater than that of a man.

All sounds are created by the movements of molecules that the sound flows through. 

When a drum or a temple bell is struck, for example, the item vibrates. Air molecules shift, and sound is created as a consequence of these vibrations. 

As the vibration amplitude is increased, a quieter sound is made, and when the vibration frequency is increased, a higher-pitched sound is detected. In reality, an organism’s capacity to hear is dictated by the strength of vibrations. 

  • Forced vibrations
    Forced vibrations are the motions of a body that arise under the impact of an external periodic force operating on it. When the stem of a vibrating tuning fork is pushed to the top of a table, the tabletop vibrates at the pace of the tuning fork.
  • Resonance
    Forced waves are a subset of resonance. As the frequency of an externally exerted periodic force equals the normal frequency of a muscle, the body begins to vibrate with greater amplitude. This effect is known as resonance, and large-amplitude vibrations are referred to as resonant vibrations.

In this chapter, we learned about the basics of sounds. We learned important concepts of sound like forced natural vibrations and sound quality.

  1. Mention a list of physical causes that have an effect on sound transmission.
    Turbulence in the atmosphere
    Sound waves disperse due to velocity changes in the medium if the environment in which they are moving is unstable.
    Gradient of wind
    The sound that travels with the wind bends downwards, and the sound that travels towards the wind bends upwards.
    Gradient of temperature
    In a humid atmosphere above the earth’s surface, sound waves propagate further. Sound waves are refracting upwards in this field. The refraction would be downwards if the temperature decreases at higher altitudes.
  2. What feature of sound is influenced by temperature change?
    Temperature fluctuations influence the wavelength of sound. The wavelength of sound is influenced by temperature fluctuations.
  3. In sonography, what waves are used?
    Sonography makes use of ultrasonic waves.

  4. What exactly do you mean when you say “echo”?
    Echo is a delayed representation of the sound that enters the audience after the actual sound.

  5. What are the three different forms of sound?
    Mechanical waves are classified into three categories: transverse waves, longitudinal waves, and surface waves.

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High School Physics

  • Alternating Current
  • Atoms
  • Communication Systems
  • Current Electricity
  • Dual nature of Radiation and Matter
  • Electric Charges and Fields
  • Electricity
  • Electromagnetic Induction
  • Electromagnetic Waves
  • Electron Beams and Radioactivity
  • Electrons and Photons
  • Electrostatic Potential and Capacitance
  • Fluid Pressure
  • Force and Acceleration
  • Force And Laws Of Motion
  • Gravitation
  • Internal Energy
  • Kinetic Theory
  • Law of motion
  • Light – Reflection And Refraction
  • Magnetic Effects Of Electric Current
  • Magnetism and Matter
  • Management Of Natural Resources
  • Mechanical properties of Fluids
  • Mechanical properties of Solids
  • Motion
  • Motion in a plane
  • Motion in a straight line
  • Moving Charges and Magnetism
  • Nuclear Energy
  • Nuclei
  • Oscillations
  • Our Environment
  • Paths of Heat
  • Physical world
  • Ray optics and optical instruments
  • Semiconductor Devices
  • Semiconductor Electronics: Materials, Devices and Simple Circuits
  • Simple Machines
  • Sound
  • Sources Of Energy
  • Specific and Latent Heats
  • Spherical Mirrors
  • Static Electricity
  • Systems of Particles and Rotational motion
  • Thermal properties of matter
  • Thermodynamics
  • Units and Measurement
  • Vectors, Scalar Quantities and Elementary Calculus
  • Wave Optics
  • Waves
  • Work, Power and Energy

High School Chemistry

  • Acids, Bases and Salts
  • Alcohols, Phenols and Ethers
  • Aldehydes, Ketones and Carboxylic Acids
  • Aliphatic and Aromatic Hydrocarbons
  • Alkyl and Aryl Halides
  • Amines
  • Analytical Chemistry 
  • Atomic Structure
  • Atoms And Molecules
  • Basic concepts of Chemistry
  • Biomolecules
  • Carbon And Its Compounds
  • Carboxylic acids and Acid Derivatives
  • Chemical Bonding and Molecular Structures
  • Chemical Energetics
  • Chemical Equilibria
  • Chemical Kinetics
  • Chemical Reactions And Equations
  • Chemical Reactions and Their Mechanisms
  • Chemistry in Everyday Life
  • Chemistry of p-Block elements
  • Chemistry of Transition and Inner Transition
  • Classification of Elements
  • Coordination Compounds
  • Cyanide, Isocyanide, Nitro compounds and Amines
  • Electrochemistry
  • Electrolysis
  • Elements, Compounds and Mixtures
  • Environmental Chemistry
  • Equilibrium
  • Ethers and Carbonyl compounds
  • Haloalkanes and Haloarenes
  • Hydrocarbons
  • Hydrogen
  • Ideal solutions
  • Introduction to Organic Chemistry
  • Ionic equilibria
  • Matter
  • Matter Around Us
  • Matter In Our Surroundings
  • Metallurgy
  • Metals And Non-Metals
  • Mole Concept and Stoichiometry
  • Natural Resources
  • Organic Chemistry – Basic Principles
  • Periodic Classification of Elements
  • Physical and Chemical Changes
  • Physical and Chemical Properties of Water
  • Polymers
  • Preparation, Properties and Uses of Compounds
  • Principles and Processes of Isolation of Elements
  • Redox Reactions
  • Relative Molecular Mass and Mole
  • States of Matter
  • Structure Of The Atom
  • Study of Compounds
  • Study of Gas Laws
  • Study of Representative Elements
  • Surface Chemistry
  • The d-block and f-block elements
  • The Gaseous State
  • The p-Block Elements
  • The Periodic Table
  • The s-Block Elements
  • The Solid State
  • Thermodynamics

High School Biology

  • Absorption and Movement of Water in Plants
  • Adolescent Issues
  • Anatomy of Flowering Plants
  • Animal Kingdom
  • Bacteria and Fungi-Friends and Foe
  • Biodiversity and Conservation
  • Biofertilizers
  • Biological Classification
  • Biomedical Engineering
  • Biomolecules
  • Biotechnology and its Applications
  • Biotic Community
  • Body Fluids and Circulation
  • Breathing and Exchange of Gases
  • Cell – Unit of Life
  • Cell Cycle and Cell Division
  • Cell Division and Structure of Chromosomes
  • Cell Reproduction
  • Cellular Respiration
  • Chemical Coordination and Integration
  • Circulation
  • Control And Coordination
  • Crop Improvement
  • Digestion and Absorption
  • Diversity In Living Organisms
  • Ecosystem
  • Environmental Issues
  • Excretory Products and their Elimination
  • Flowering Plants
  • Genes and Chromosomes
  • Health and Diseases
  • Health and Its Significance
  • Heredity And Evolution
  • Heredity and Variation
  • How Do Organisms Reproduce?
  • Human Diseases
  • Human Eye And Colourful World
  • Human Health and Disease
  • Human Population
  • Human Reproduction
  • Hygiene
  • Improvement In Food Resources
  • Integumentary System- Skin
  • Kingdom Fungi
  • Kingdom Monera
  • Kingdom Protista
  • Life Processes
  • Locomotion and Movement
  • Microbes in Human Welfare
  • Mineral Nutrition
  • Molecular Basis of Inheritance
  • Morphology of Flowering Plants
  • Neural Control And Coordination
  • Nutrition in Human Beings
  • Organism and Population
  • Photosynthesis
  • Photosynthesis in Higher Plants
  • Plant Growth and Development
  • Plant Kingdom
  • Pollination and Fertilization
  • Pollution; Sources and its effects
  • Principles of Inheritance and Variation
  • Reproduction and Development in Angiosperms
  • Reproduction in Organisms
  • Reproductive Health
  • Respiration in Human Beings
  • Respiration in Plants
  • Respiratory System
  • Sexual Reproduction in Flowering Plants
  • Strategies for Enhancement in Food Production
  • Structural Organisation in Animals
  • Structural Organisation of the Cell
  • The Endocrine System
  • The Fundamental Unit Of Life
  • The Living World
  • The Nervous System and Sense Organs
  • Tissues
  • Transpiration
  • Transport in Plants

High School Math

  • Algebra – Arithmatic Progressions
  • Algebra – Complex Numbers and Quadratic Equations
  • Algebra – Linear Inequalities
  • Algebra – Pair of Linear Equations in Two Variables
  • Algebra – Polynomials
  • Algebra – Principle of Mathematical Induction
  • Algebra – Quadratic Equations
  • Binomial Theorem
  • Calculus – Applications of Derivatives
  • Calculus – Applications of the Integrals
  • Calculus – Continuity and Differentiability
  • Calculus – Differential Equations
  • Calculus – Integrals
  • Geometry – Area
  • Geometry – Circles
  • Geometry – Conic Sections
  • Geometry – Constructions
  • Geometry – Introduction to Euclid’s Geometry
  • Geometry – Three-dimensional Geometry
  • Geometry – Lines and Angles
  • Geometry – Quadrilaterals
  • Geometry – Straight Lines
  • Geometry – Triangles
  • Linear Programming
  • Matrices and Determinants
  • Mensuration – Areas
  • Mensuration – Surface Areas and Volumes
  • Number Systems
  • Number Systems – Real Numbers
  • Permutations and Combinations
  • Probability
  • Sequence and Series
  • Sets and Functions
  • Statistics 
  • Trignometry – Height and Distance
  • Trignometry – Identities
  • Trignometry – Introduction

Middle School Science

  • Acids, Bases And Salts
  • Air and Its Constituents
  • Basic Biology
  • Body Movements
  • Carbon and Its Compounds
  • Cell – Structure And Functions
  • Changes Around Us
  • Chemical Effects Of Electric Current
  • Chemistry in Your Life
  • Coal And Petroleum
  • Combustion And Flame
  • Components Of Food
  • Conservation Of Plants And Animals
  • Crop Production And Management
  • Electric Current And Its Effects
  • Electricity And Circuits
  • Elements and Compounds
  • Fibre To Fabric
  • Food production and management
  • Force And Pressure
  • Forests: Our Lifeline
  • Friction
  • Fun With Magnets
  • Garbage In, Garbage Out
  • Getting To Know Plants
  • Health and Hygiene
  • Heat
  • Hydrogen
  • Life Processes: Nutrition in Animals and Plants
  • Light, Shadows And Reflections
  • Materials: Metals And Non-Metals
  • Matter and Its States
  • Metals and Non-metals
  • Micro Organisms: Friend And Foe
  • Motion And Measurement Of Distances
  • Motion And Time
  • Nutrition In Animals
  • Nutrition In Plants
  • Organization in Living Things
  • Our Environment
  • Physical And Chemical Changes
  • Pollution and conservation
  • Pollution Of Air And Water
  • Reaching The Age Of Adolescence
  • Reproduction In Animals
  • Reproduction In Plants
  • Respiration In Organisms
  • Rocks and Minerals
  • Separation Of Substances
  • Simple Machines
  • Soil
  • Some Natural Phenomena
  • Sorting Materials Into Groups
  • Sound
  • Stars And The Solar System
  • Structure of Atom
  • Synthetic Fibers And Plastics
  • The Living Organisms And Their Surroundings
  • Transfer of Heat
  • Transformation of Substances
  • Transportation In Animals And Plants
  • Universe
  • Waste-water Story
  • Water: A Precious Resource
  • Weather, Climate And Adaptations Of Animals To Climate
  • Winds, Storms And Cyclones

Middle School Math

  • Addition
  • Area and Its Boundary
  • Boxes and Sketches
  • Data Handling
  • Fun With Numbers
  • Heavy and Light
  • How Many
  • Long And Short
  • Mapping
  • Measurement
  • Money
  • Multiplication and Factors
  • Multiply and Divide
  • Numbers
  • Parts and Wholes
  • Pattern Recognition
  • Patterns
  • Play With Patterns
  • Rupees And Paise
  • Shapes And Angles
  • Shapes And Designs
  • Shapes and Space
  • Similarity
  • Smart Charts
  • Squares
  • Subtraction
  • Tables And Shares
  • Tenths and Hundredths
  • Time
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