Grade 9
  1. Mechanics  1.1. Motion  1.1.1. Types of motion  1.1.2. Distance and displacement  1.1.3. Speed and Velocity  1.1.4. Acceleration  1.1.5. Graphical representation of motion  1.1.6. Equations of motion  1.1.7. Uniform and non-uniform motion  1.1.8. Free fall and acceleration due to gravity  1.1.9. Relative speed  1.1.10. Circular motion  1.2. Laws of force and motion  1.2.1. The concept of force  1.2.2. newton's first law of motion  1.2.3. Newton's second law of motion  1.2.4. Newton's third law of motion  1.2.5. Inertia and types of inertia  1.2.6. Motion  1.2.7. Conservation of momentum  1.2.8. Application of Newton's laws in daily life  1.2.9. Types of Forces (Contact and Non-Contact)  1.2.10. Friction and its effects  1.3. Gravitational force  1.3.1. Newton's law of universal gravitation  1.3.2. Importance of Gravitational Force  1.3.3. Acceleration due to gravity  1.3.4. Free fall and weightlessness  1.3.5. Mass and weight  1.3.6. Variation of g with height and depth  1.3.7. Kepler's laws of planetary motion  1.3.8. Satellites and their orbits  1.4. Work, Energy and Power  1.4.1. Concept of work  1.4.2. Positive and negative actions  1.4.3. Work done by constant and variable force  1.4.4. Energy and its forms  1.4.5. Kinetic energy and potential energy  1.4.6. Law of conservation of energy  1.4.8. Commercial unit of energy  1.4.9. Work–energy theorem  1.5. Simple machines  1.5.1. Types of simple machines  1.5.2. Mechanical advantage  1.5.3. Machine efficiency  1.5.4. Levers and their types  1.5.5. Pulleys and Inclined Planes  1.5.6. Gears and their uses
  2. Properties of matter  2.1. States of matter  2.1.1. Solids, liquids and gases  2.1.2. Properties of different states of matter  2.1.3. Change in state of matter  2.1.4. Plasma and Bose–Einstein condensate  2.2. Density and pressure  2.2.1. Concept of density and relative density  2.2.2. Pressure in solids, liquids and gases  2.2.3. Pascal's law and its applications  2.2.4. Atmospheric pressure and its variations  2.2.5. Surface tension and capillarity  2.3. Buoyancy and Archimedes' principle  2.3.1. Buoyant force  2.3.2. Archimedes principle  2.3.3. Applications of Archimedes' Principle  2.3.4. floating and sinking objects  2.3.5. Theory of Flotation and Archimedes' Principle
  3. Heat and Thermodynamics  3.1. Temperature and heat  3.1.1. Concept of heat and temperature  3.1.2. Temperature measurement  3.1.3. Temperature scales  3.2. Heat transfer  3.2.1. Conduction of heat  3.2.2. Convection of heat  3.2.3. heat radiation  3.2.4. Applications of heat transfer  3.2.5. Thermal conductivity  3.3. Thermal expansion  3.3.1. Expansion of solids, liquids and gases  3.3.2. Abnormal expansion of water  3.3.3. Applications of Thermal Expansion  3.4. Specific heat capacity and latent heat  3.4.1. Concept of specific heat capacity  3.4.2. Measurement and applications of specific heat  3.4.3. Latent heat of fusion and vaporization  3.4.4. Heat Engines and Efficiency
  4. Waves and sound  4.1. Waves and their types  4.1.1. Mechanical and electromagnetic waves  4.1.2. Longitudinal and Transverse Waves  4.1.3. Properties of Waves  4.1.4. Wavelength, frequency and speed of the wave  4.1.5. Superimposition of waves  4.2. Sound waves  4.2.1. Nature and transmission of sound  4.2.2. Speed of sound in different mediums  4.2.3. Reflection of sound and echo  4.2.4. Sonar and ultrasound  4.2.5. Resonance and pulsation  4.3. Sound characteristics  4.3.1. Intensity, loudness and quality of sound  4.3.2. Doppler effect in sound
  5. Lighting and Optics  5.1. Reflection of light  5.1.1. Laws of reflection  5.1.2. Reflection from a plane mirror  5.1.3. Reflection from a spherical mirror  5.1.4. Image formation by concave and convex mirrors  5.1.5. Applications of Reflection  5.2. Refraction of light  5.2.1. Laws of refraction  5.2.2. Refractive index  5.2.3. Refraction through a glass slab  5.2.4. Refraction in water and air  5.2.5. Lenses and their types  5.2.6. Image formation by convex and concave lenses  5.2.7. Total internal reflection and its applications  5.3. Dispersion and scattering of light  5.3.1. Spectrum of white light  5.3.2. Prisms and Dispersion  5.3.3. Tyndall effect and blue sky
  6. Electricity and Magnetism  6.1. Electric charge and static electricity  6.1.1. The concept of electric charge  6.1.2. Charging by friction, contact and induction  6.1.3. Electroscope and its working  6.2. Current Electricity  6.2.1. The concept of electric current  6.2.2. Ohm's Law and Resistance  6.2.3. Factors affecting resistance  6.2.4. Series and Parallel Circuits  6.2.5. Heating effect of electric current  6.2.6. Electric power and energy  6.3. Magnetism  6.3.1. Natural and artificial magnets  6.3.2. Properties of magnets  6.3.3. Earth's magnetism  6.3.4. Magnetic field and field lines  6.3.5. Electromagnets and their applications
  7. Modern Physics  7.1. structure of the atom  7.1.1. Atomic Structure and Subatomic Particles  7.1.2. Electrons, Protons, and Neutrons  7.1.3. Rutherford and Bohr model  7.2. Radioactivity  7.2.1. Types of radioactive emissions  7.2.2. Half-life and radioactive decay  7.2.3. Uses and Hazards of Radioactivity
  8. Space science and astronomy  8.1. The universe and its components  8.1.1. Stars and galaxies  8.1.2. Planets and Solar System  8.2. Satellites  8.2.1. Natural and artificial satellites  8.2.2. Use of satellites

Grade 9 → Heat and Thermodynamics → Specific heat capacity and latent heat ↓


Measurement and applications of specific heat


Introduction

Have you ever wondered why water takes longer to heat up than metal, or why deserts cool down faster at night despite high temperatures during the day? The answer lies in the concept of specific heat capacity. Understanding specific heat is fundamental in physics, as it explains many everyday phenomena and is important in a variety of applications. Let's take a deeper look at specific heat and latent heat, their measurement, applications, and their importance.

What is specific heat?

Specific heat is the amount of heat per unit mass needed to raise the temperature by one degree Celsius. It is an inherent property of substances that results from molecular structure and bonding, which determines how substances absorb and transfer heat.

Understanding the Formula

The formula for calculating the specific heat is:

q = mcΔT

Where:

  • q is the heat added (in joules, J).
  • m is the mass of the substance (in kilograms).
  • c is the specific heat capacity (in joules per kilogram per degree Celsius, J/kg°C).
  • ΔT is the change in temperature (in Celsius, °C).
Specific heat capacity is a physical property that can change with temperature and pressure, but is often considered constant over small temperature ranges.

Example calculation

Let's understand with a simple example. Suppose you have 2 kg of water and you want to increase its temperature by 3 °C. The specific heat capacity of water is about 4,186 J/kg°C. Using the formula:

q = mcΔT = 2 kg * 4186 J/kg°C * 3°C = 25116 J

This means that 25,116 joules of energy is required.

Why do different substances have different specific heat capacities?

Different substances have different atomic and molecular arrangements, which affect how they store and release energy. Substances with tightly bound molecules, such as metals, generally have lower specific heat capacities than substances with loosely bound hydrogen bonds, such as water. This is why metals heat up and cool down faster than water.

Looking at heat transfer through examples

Water 4,186 J/kg°C Metal 385 J/kg °C

Applications of specific heat

Specific heat capacity has many practical applications:

  • Cooking: Water's high specific heat makes it excellent for cooking. It can store and transfer a lot of heat without dramatic temperature changes, leading to even cooking.
  • Climate control: Oceans regulate Earth's climate by absorbing heat during the day and releasing it at night due to their large heat capacity.
  • Thermal storage systems: Materials with a high specific heat are used in thermal storage to retain thermal energy for later use, such as in solar heating systems.
  • Insulation: Specific heat is an important factor in insulation materials, affecting their effectiveness in resisting temperature changes.

Comparison with latent heat

While specific heat deals with temperature changes, latent heat involves phase changes at a constant temperature, such as melting or boiling. Latent heat does not raise the temperature, despite adding thermal energy, but rather facilitates a change of state.

The formula to calculate latent heat is:

Q = mL

Where:

  • Q is the heat absorbed or released (in joules, J).
  • m is the mass of the substance (in kilograms).
  • L is the latent heat (in joules per kilogram, J/kg).
Latent heat varies according to the type of phase change, such as from solid to liquid (latent heat of fusion) or liquid to gas (latent heat of vaporization).

Example of calculating latent heat

Consider melting 1 kg of ice at 0°C, where the latent heat of fusion for ice is about 334,000 J/kg. The energy required is:

Q = mL = 1 kg * 334,000 J/kg = 334,000 J

This energy is necessary to melt the ice without changing its temperature.

Visual representation of phase change

solid to liquid Merger liquid to gas Evaporation

Real-world implications of latent heat

Latent heat is important in weather patterns. Cloud formation and precipitation occur as a result of latent heat released during the condensation of water vapor in the atmosphere. This process powers storm systems and affects the heat distribution on Earth. Refrigeration and air conditioning also rely on the principles of latent heat for efficient cooling, where substances absorb or release heat during phase changes to regulate temperature.

Conclusion

The study of specific heat and latent heat is essential in understanding both everyday phenomena and advanced scientific processes. These properties define how substances absorb, store, and transfer heat, affecting climate, cooking, technology, and more. By exploring these concepts, students can better understand how energy interactions shape our world and apply this knowledge in practical contexts.


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Measurement and applications of specific heat

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