5. Conclusion: Sound needs a medium, like air, to travel. As air is removed from the bell jar, there are fewer particles to carry the sound, so the sound becomes weaker. When all the air is removed, no sound is heard because there is no medium to transmit the sound waves.
Topics
Matter in Our Surroundings
- Matter (Substance)
- Characteristics of Particles (Molecules) of Matter
- The Solid State
- The Liquid State
- The Gaseous State
- Plasma
- Bose-einstein Condensate
- Heat and change of physical state
- Concept of Evaporation
- Concept of Melting (Fusion)
- Concept of Boiling (Vaporization)
- Concept of Sublimation
- Concept of Freezing (Solidification)
- Concept of Condensation (Liquefaction)
- Concept of Desublimation (Deposition)
Is Matter Around Us Pure
- Matter (Substance)
- Natural substances
- Mixture
- Types of Mixtures
- Solution
- Concentration of a Solution
- Suspension Solution
- Colloidal Solution
- Evaporation Method
- Solvent Extraction (Using a Separating Funnel Method)
- Sublimation Method
- Chromatography Method
- Simple Distillation Method
- Fractional Distillation Method
- Crystallisation Method
- Classification of Change: Physical Changes
- Chemical Reaction
- Pure Substances
- Compound
- Elements
Atoms and Molecules
- History of Atom
- Laws of Chemical Combination
- Law of Conservation of Mass
- Law of Constant Proportions (Law of Definite Proportions)
- Dalton’s Atomic Theory
- Atoms: Building Blocks of Matter
- Symbols Used to Represent Atoms of Different Elements
- Atomic Mass
- Relative Atomic Mass (RAM)
- Molecules
- Classification of Molecules
- Difference Between Atoms and Molecules
- Ions (Radicals) and Its Types
- Chemical Formula or Molecular Formula
- Molecular Mass
- Formula Unit Mass
- Mole Concept
- Atoms and Molecules Numericals
Structure of the Atom
- Existence of Charged Particles in Matter
- Atoms: Building Blocks of Matter
- Discovery of Charged Particles in Matter
- Protons (p)
- Electrons (e)
- Neutrons (n)
- J. J. Thomson’s Atomic Model
- Advantage and Limitations of Thomson’s Atomic Model
- Lord Rutherford’s Atomic model
- Limitations of Rutherford’s Atomic Model
- Neils Bohr’s Model of an Atom
- Electronic Configuration of Atom
- Valency
- Different Ways to Determine Valency
- Atomic Number (Z), Mass Number (A), and Number of Neutrons (n)
- Atomic Mass
- Isotopes
- Uses of Radioactive Isotopes
- Isobars
- Atoms and Molecules Numericals
The Fundamental Unit of Life
- Cell: Structural and Functional Unit of Life
- The Invention of the Microscope and the Discovery of Cell
- Cell Theory
- Organisms Show Variety in Cell Number, Shape and Size
- Prokaryotic and Eukaryotic Cell
- Simple Diffusion
- Concept of Osmosis
- Osmotic Pressure
- Structure of the Cell
- Plasma Membrane
- Semi-permeable Membrane (Cell Membrane)
- Cell Wall - “Supporter and Protector”
- Nucleus - “Brain” of the Cell
- Cytoplasm - “Area of Movement”
- Endoplasmic Reticulum (ER)
- Golgi Apparatus - "The delivery system of the cell"
- Lysosome - “Suicidal Bag”
- Mitochondria - “Power House of the Cell”
- Plastids
- Non-living Substances Or Cell Inclusion
- Plant Cell and Animal Cell
- Cell Division: an Essential Life Process
Tissues
- Tissues - “The Teams of Workers”
- Plant and Animals Tissue
- Plant Tissues
- Meristems or Meristematic Tissues
- Permanent Tissue
- Simple Permanent Tissues (Supporting Tissue)
- Complex Permanent Tissues
- Complex Permanent Tissue: Xylem Structure and Function (Conducting Tissue)
- Complex Permanent Tissue: Phloem Structure and Function (Conducting Tissue)
- Animal Tissues
- Epithelial Tissue
- Connective Tissue
- Muscular Tissue
- Nervous Tissue
Motion
- Motion and Rest
- Describing Motion
- Motion Along a Straight Line
- Types of Motion
- Measuring the Rate of Motion - Speed with Direction
- Rate of Change of Velocity
- Distance and Displacement
- Displacement - Time Graph Or Distance - Time Graph
- Velocity - Time Graphs
- Equations of Motion by Graphical Method
- Derivation of Velocity - Time Relation by Graphical Method
- Derivation of Displacement - Time Relation by Graphical Method
- Derivation of Displacement - Velocity Relation by Graphical Method
- Uniform Circular Motion (UCM)
- Motion (Numerical)
Diversity in Living Organisms
- Biodiversity
- Biological Classification
- Classification of Living Organisms
- Taxonomic Hierarchy of Living Organisms: Unit of Classification
- Five Kingdom Classification
- Kingdom Monera
- Kingdom Protista
- Kingdom Fungi
- Classification of Kingdom Plantae
- Kingdom Animalia
- Differences Between Plantae (Plants) and Animalia (Animals)
- Classification of Kingdom Plantae
- Kingdom Plantae: Thallophyta (Algae)
- Kingdom Plantae: Thallophyta (Fungi)
- Division II- Bryophytes
- Division III- Pteridophytes
- Division I-Gymnosperms
- Division II- Angiosperms
- Kingdom Animalia
- Phylum: Porifera
- Phylum: Cnidaria/Coelenterata
- Phylum: Platyhelminthes
- Invertebrate: Phylum Nematoda
- Phylum: Annelida
- Phylum: Arthropoda
- Phylum: Mollusca
- Phylum: Echinodermata
- Subphylum: Prochordata
- Chordata: Vertebrata
- Invertebrata and Vertebrata
- Taxonomy and Systematics
- Nomenclature
Force and Laws of Motion
Gravitation
Work and Energy
Sound
- Sound
- Production of Sound
- Propagation of Sound
- Sound Need a Medium to Travel
- Sound Waves Are Longitudinal Waves
- Characteristics of a Sound Wave
- Speed of Sound (Velocity of Sound)
- Reflection of Sound
- Echoes
- Reverberation
- Uses of Multiple Reflection of Sound
- Range of Hearing in Humans
- Ultrasonic Sound Or Ultrasound
- SONAR
- Human Ear
- Sound (Numerical)
Improvement in Food Resources
- Improvements in Food Resources
- Improvement in Crop Yields
- Crop Variety Improvement
- Crop Production Improvement
- Crop Protection Management
- Methods to Replenish Nutrients in Your Soil
- Manuring (Biomanuring)
- Fertilizers
- Improved methods of agriculture
- Agricultural Assistance Programme
- Animal Husbandry (Livestock)
- Dairy Farming
- Poultry Farming
- Pisciculture (Fish Farming)
- Apiculture (Bee Farming)
Why Do We Fall ill
- Health
- Disease
- Categories of Disease
- Acute and Chronic Diseases
- Causes of Disease
- Communicable Or Infectious Diseases
- Infectious Agents
- Manifestation of Diseases
- Modes of Transmission of Diseases
- Organ-specific and Tissue-specific Manifestations
- Principles of Prevention of Diseases
- Principles of Treatment of Diseases
Natural Resources
- Natural Resources
- Biosphere: The Domain of Life
- Air is a Mixture
- Atmosphere and Its Layers
- Wind: The Movement of Air
- Rain
- Water: Our Lifeline
- Where Do We Get Water From?
- Availability of Water
- Importance of Water
- Water Pollution and Its Causes
- Mineral Riches in the Soil
- Biogeochemical Cycle
- Water Cycle
- Nitrogen Cycle
- The Carbon Cycle
- The Oxygen Cycle
- Ozone
- Ozone Layer Depletion
- Introduction
- Experiment 1
- Experiment 2
Introduction:
Sound propagation refers to the process by which sound waves travel through a medium from their source to a receiver, such as our ears. This movement of sound occurs due to the vibration of particles in the medium (air, liquids, or solids), which carry energy from one point to another without transferring matter.
- Sound waves are the result of vibrations, which produce sound. These waves move out in all directions from the source.
- The material through which sound waves travel is called the medium. This can be air, water, or any solid material.
- Sound propagates more clearly through a liquid than through air, and it is heard most clearly through a solid.
- Sound is transmitted faster through a liquid than through a gas and faster through a solid than through a liquid.
- Sound is said to be propagated when sound waves spread in all directions from a source of sound.
- The substance around a source of sound through which sound waves spread is called the medium of propagation of sound.
Experiment 1
1. Aim: To explore how sound travels through different materials (air and water) using balloons and to understand sound transmission through solids.
2. Requirements: two balloons, water, and a large table.
3. Procedure
I. Balloon experiment:
- Fill one balloon with air and the other with water.
- Press the balloon filled with air against your ear and rub a finger on its surface. Note the sound quality.
- Repeat the process with the water-filled balloon and compare which balloon transmits sound more clearly.
II. Table Sound Experiment:
- Stand at one end of a large table with a friend at the other end.
- Have the friend knock lightly on the table. Listen to the sound.
- Press your ear to the table and ask your friend to knock again. Observe any difference in the sound.
4. Conclusion
- Balloon Experiment: The sound is clearer when heard through the water-filled balloon because water, being denser than air, allows sound waves to travel more effectively. This improves the sound's clarity and volume.
- Table Experiment: The sound of the knock becomes clearer and louder when the ear is placed against the table. This is because sound travels faster and more efficiently through solids, like the table, compared to air. This shows how the material through which sound travels affects its transmission.
Propagation of sound
Experiment 2
1. Aim: To demonstrate that sound generation and propagation require a medium, such as air.
2. Requirements: vacuum-tight bell jar, electric bell, vacuum pump, power supply for the electric bell, and smooth horizontal surface to place the bell jar.
3. Procedure
- Place the electric bell inside a vacuum-tight bell jar connected to a vacuum pump. Connect the bell to a power supply through the jar's lid.
- Initially, keep the bell jar filled with air and the vacuum pump off. Switch on the electric bell and listen to its sound outside the jar.
- Turn on the vacuum pump to gradually remove air from the jar. As the air is removed, the ringing sound becomes fainter.
- After sufficient air is removed, the sound becomes almost inaudible, showing that sound needs air (or a medium) to travel.
Medium is necessary for the propagation of sound
4. Observation: The intensity of the sound decreases as the air inside the bell jar is removed. When the air is nearly or completely removed, the sound is barely or not heard at all.
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