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
9.2.2 Balanced Diet Explained

Understanding a Balanced Diet

Key Concepts

1. Definition of a Balanced Diet

A balanced diet is a diet that includes a variety of foods in specific proportions to provide the necessary nutrients for optimal health and well-being.

2. Importance of a Balanced Diet

A balanced diet is crucial for maintaining energy levels, supporting growth and development, preventing chronic diseases, and promoting overall health.

3. Food Groups

A balanced diet typically includes foods from five main groups: fruits, vegetables, grains, proteins, and dairy (or alternatives).

4. Nutrient Needs

Different nutrients have specific roles in the body. A balanced diet ensures that the body receives all the essential nutrients, including vitamins, minerals, proteins, carbohydrates, and fats.

5. Portion Sizes

Portion sizes are important to ensure that the body receives the right amount of nutrients without consuming excessive calories.

6. Healthy Eating Habits

Healthy eating habits include regular meal times, avoiding overeating, and choosing nutrient-dense foods over processed or junk foods.

7. Hydration

Staying hydrated is an essential part of a balanced diet. Water is crucial for various bodily functions, including digestion, circulation, and temperature regulation.

8. Physical Activity

Physical activity complements a balanced diet by helping to maintain a healthy weight, build muscle, and improve overall fitness.

Explanation of Each Concept

1. Definition of a Balanced Diet

A balanced diet ensures that the body receives all the necessary nutrients in the right proportions. This includes a variety of foods from different food groups to meet nutritional needs.

2. Importance of a Balanced Diet

A balanced diet provides the energy and nutrients needed for daily activities, supports growth and development, and helps prevent chronic diseases such as obesity, diabetes, and heart disease.

3. Food Groups

Fruits and vegetables provide vitamins, minerals, and fiber. Grains, especially whole grains, offer carbohydrates for energy. Proteins, such as meat, fish, beans, and nuts, are essential for building and repairing tissues. Dairy products or alternatives provide calcium and other minerals. Fats and oils, in moderation, are necessary for energy and absorption of fat-soluble vitamins.

4. Nutrient Needs

Nutrients like vitamins A, C, and E are antioxidants that protect cells. Calcium and vitamin D are crucial for bone health. Proteins are essential for muscle growth and repair. Carbohydrates provide energy, and fats support cell function and hormone production.

5. Portion Sizes

Portion sizes vary depending on age, sex, and physical activity levels. For example, a recommended portion of fruits and vegetables is about 5 servings per day, while grains should include at least half whole grains.

6. Healthy Eating Habits

Healthy eating habits include eating a variety of foods, limiting sugary and fatty foods, and being mindful of portion sizes. Regular meal times and avoiding skipping meals can also help maintain a balanced diet.

7. Hydration

Drinking enough water is essential for digestion, circulation, temperature regulation, and waste elimination. Most people need about 8 glasses of water per day, though this can vary based on activity levels and climate.

8. Physical Activity

Regular physical activity, such as walking, running, or playing sports, helps maintain a healthy weight, build muscle, and improve cardiovascular health. It also complements a balanced diet by enhancing nutrient absorption and utilization.

Examples and Analogies

Example 1: Balanced Diet

Imagine a balanced diet as a rainbow. Each color represents a different food group, and a complete rainbow ensures that all colors (nutrients) are present.

Example 2: Nutrient Needs

Think of nutrients as different tools in a toolbox. Each tool (nutrient) has a specific job, and having all the tools ensures that the job (body function) is done properly.

Analogy: Portion Sizes

Think of portion sizes as the right amount of ingredients in a recipe. Too much or too little of any ingredient can ruin the dish, just as too much or too little of any nutrient can affect health.