Science for Grade 7
1 Introduction to Science
1-1 Definition of Science
1-2 Importance of Science in Daily Life
1-3 Scientific Method
1-3 1 Observation
1-3 2 Hypothesis
1-3 3 Experimentation
1-3 4 Analysis
1-3 5 Conclusion
2 Matter and Its Properties
2-1 States of Matter
2-1 1 Solid
2-1 2 Liquid
2-1 3 Gas
2-2 Properties of Matter
2-2 1 Mass
2-2 2 Volume
2-2 3 Density
2-2 4 Solubility
2-3 Changes in Matter
2-3 1 Physical Changes
2-3 2 Chemical Changes
2-4 Mixtures and Solutions
2-4 1 Types of Mixtures
2-4 2 Separation Techniques
3 Force and Motion
3-1 Types of Forces
3-1 1 Gravitational Force
3-1 2 Frictional Force
3-1 3 Magnetic Force
3-1 4 Electrostatic Force
3-2 Motion
3-2 1 Speed and Velocity
3-2 2 Acceleration
3-2 3 Newton's Laws of Motion
3-2 3-1 First Law (Inertia)
3-2 3-2 Second Law (Force and Acceleration)
3-2 3-3 Third Law (Action and Reaction)
4 Energy
4-1 Forms of Energy
4-1 1 Kinetic Energy
4-1 2 Potential Energy
4-1 3 Thermal Energy
4-1 4 Electrical Energy
4-1 5 Light Energy
4-1 6 Sound Energy
4-2 Energy Conversion
4-2 1 Mechanical to Electrical
4-2 2 Chemical to Thermal
4-2 3 Light to Electrical
4-3 Conservation of Energy
5 Heat and Temperature
5-1 Temperature
5-1 1 Measurement of Temperature
5-1 2 Temperature Scales
5-2 Heat Transfer
5-2 1 Conduction
5-2 2 Convection
5-2 3 Radiation
5-3 Effects of Heat
5-3 1 Expansion
5-3 2 Change of State
6 Light and Sound
6-1 Light
6-1 1 Sources of Light
6-1 2 Reflection
6-1 3 Refraction
6-1 4 Lenses and Mirrors
6-2 Sound
6-2 1 Production of Sound
6-2 2 Properties of Sound
6-2 3 Reflection of Sound
6-2 4 Applications of Sound
7 Earth and Space
7-1 Earth's Structure
7-1 1 Crust
7-1 2 Mantle
7-1 3 Core
7-2 Earth's Atmosphere
7-2 1 Layers of the Atmosphere
7-2 2 Weather and Climate
7-3 Solar System
7-3 1 Planets
7-3 2 Sun
7-3 3 Moon
7-4 Space Exploration
7-4 1 Rockets
7-4 2 Satellites
7-4 3 Space Stations
8 Living Organisms and Ecosystems
8-1 Classification of Living Organisms
8-1 1 Kingdoms
8-1 2 Species
8-2 Ecosystems
8-2 1 Components of an Ecosystem
8-2 2 Food Chains and Webs
8-3 Adaptations
8-3 1 Physical Adaptations
8-3 2 Behavioral Adaptations
8-4 Human Impact on Ecosystems
8-4 1 Pollution
8-4 2 Conservation Efforts
9 Health and Nutrition
9-1 Human Body Systems
9-1 1 Circulatory System
9-1 2 Respiratory System
9-1 3 Digestive System
9-1 4 Nervous System
9-2 Nutrition
9-2 1 Essential Nutrients
9-2 2 Balanced Diet
9-3 Diseases and Prevention
9-3 1 Infectious Diseases
9-3 2 Non-infectious Diseases
9-3 3 Hygiene and Prevention
10 Environmental Science
10-1 Natural Resources
10-1 1 Renewable Resources
10-1 2 Non-renewable Resources
10-2 Pollution
10-2 1 Air Pollution
10-2 2 Water Pollution
10-2 3 Soil Pollution
10-3 Sustainable Development
10-3 1 Importance of Sustainability
10-3 2 Sustainable Practices
10-4 Climate Change
10-4 1 Causes of Climate Change
10-4 2 Effects of Climate Change
10-4 3 Mitigation Strategies
4.3 Conservation of Energy Explained

Understanding the Conservation of Energy

Key Concepts

1. Definition of Conservation of Energy

The Conservation of Energy is a fundamental principle in physics that states energy cannot be created or destroyed, only transformed from one form to another.

2. Law of Conservation of Energy

The Law of Conservation of Energy states that the total energy of an isolated system remains constant over time. This means that while energy can change forms, the total amount of energy in the system remains the same.

3. Energy Transformations

Energy transformations occur when energy changes from one form to another. For example, when a ball falls from a height, its potential energy is converted into kinetic energy.

4. Practical Applications

The Conservation of Energy has practical applications in various fields, including engineering, physics, and everyday life.

Explanation of Each Concept

1. Definition of Conservation of Energy

The Conservation of Energy principle means that in any closed system, the total amount of energy is always the same. This principle is crucial for understanding how energy moves and changes in different systems.

2. Law of Conservation of Energy

According to the Law of Conservation of Energy, energy can neither be created nor destroyed. For instance, when you burn a piece of wood, the chemical energy stored in the wood is converted into thermal energy and light, but the total energy remains constant.

3. Energy Transformations

Energy transformations are everywhere. When you ride a bicycle, you convert chemical energy from your body into mechanical energy to move the bike. Similarly, when a light bulb is turned on, electrical energy is converted into light and thermal energy.

4. Practical Applications

Understanding the Conservation of Energy helps engineers design more efficient machines and systems. For example, in hydroelectric power plants, the potential energy of water stored in a dam is converted into electrical energy. In everyday life, this principle helps us understand how energy is conserved in various activities, such as cooking and transportation.

Examples and Analogies

Example 1: Pendulum

A pendulum is a classic example of energy transformation. At the highest point, the pendulum has maximum potential energy. As it swings down, this potential energy is converted into kinetic energy. At the bottom of the swing, the kinetic energy is at its maximum, and as it swings back up, the kinetic energy is converted back into potential energy.

Example 2: Roller Coaster

In a roller coaster, the car gains potential energy as it climbs the first hill. As the car descends, this potential energy is converted into kinetic energy, allowing the car to move. Throughout the ride, the total energy remains constant, even though the forms of energy change.

Analogy: Energy as a Budget

Think of energy like a budget. You can allocate your budget to different expenses, but the total amount of money (energy) remains the same. Similarly, energy can be allocated to different forms, but the total amount of energy in a system is conserved.

Conclusion

Understanding the Conservation of Energy is crucial for explaining how energy is transformed and conserved in various systems. By recognizing this principle, we can better appreciate the energy dynamics in our daily lives and the various ways energy is harnessed and utilized.