Core Science Concepts: Chemistry, Optics, Biology, and Climate

Chemistry Fundamentals and Reactions

Chemical Bonding Types

• Ionic Bonding: Metal + Non-metal → Electrons are transferred.
• Covalent Bonding: Non-metal + Non-metal → Electrons are shared.

Chemical Naming Conventions

• Ionic Naming: Metal + Non-metal (ending in “-ide”). Use Roman numerals for multivalent metals. Includes polyatomic ions.
• Molecular Compounds: Use prefixes (mono-, di-, tri-, etc.).
• Diatomic Elements: H₂, O₂, F₂, Br₂, I₂, N₂, Cl₂.

Properties of Compounds

• Ionic Compounds: Solid state, high melting/boiling points, conducts electricity when dissolved (aqueous).
• Molecular Compounds: Low melting/boiling points, poor electrical conductors.

Balancing Chemical Equations

The process follows the Law of Conservation of Mass:

1. Word Equation
2. Skeleton Equation (unbalanced)
3. Balanced Equation

Types of Chemical Reactions

• Synthesis: A + B → AB
• Decomposition: AB → A + B
• Single Displacement: A + BC → AC + B
• Double Displacement: AB + CD → AD + CB
• Combustion:
  • Complete: CₓHᵧ + O₂ → CO₂ + H₂O
  • Incomplete: CₓHᵧ + O₂ → CO + C + H₂O

Acids and Bases

• Acids: Produce H⁺ ions, pH < 7, taste sour.
• Bases: Produce OH⁻ ions, pH > 7, taste bitter and feel slippery.
• pH Scale: Each pH unit represents a 10-fold (×10) change in acidity or basicity.
• Neutralization: Acid + Base → Salt + Water.

Key Concepts in Optics and Light

Nature of Light and Refraction

Light travels in straight lines. When light slows down in denser media, it causes refraction (bending).

Electromagnetic (EM) Spectrum

Order of increasing frequency/energy:

1. Radio waves
2. Microwaves
3. Infrared (IR)
4. Visible light
5. Ultraviolet (UV)
6. X-ray
7. Gamma ray

Reflection Principles

• Types: Specular reflection occurs on smooth surfaces; diffuse reflection occurs on rough surfaces.
• Law of Reflection: The angle of incidence equals the angle of reflection (∠incidence = ∠reflection).

Plane Mirror Image Characteristics (SALT)

• Size: Same size
• Attitude: Upright
• Location: Same distance behind the mirror
• Type: Virtual image

Curved Mirrors

• Concave Mirrors: Converging; can produce real or virtual images.
• Convex Mirrors: Diverging; always produce virtual images.

Refraction and Index of Refraction

Light bends toward the normal when entering a denser medium. The index of refraction ($n$) is calculated as $n = c/v$ (speed of light in vacuum / speed of light in medium).

Total Internal Reflection (TIR)

Occurs when the angle of incidence is greater than the critical angle, provided light is moving from a denser medium to a less dense medium.

Lenses

• Convex Lenses: Converging
• Concave Lenses: Diverging
• Image characteristics are determined using SALT and ray diagrams.

The Human Eye

Key components include the cornea, lens, retina, and optic nerve. Common vision issues are near-sightedness (myopia), far-sightedness (hyperopia), and astigmatism.

Essential Biology: Cells, Systems, and Organization

Key Cell Organelles and Functions

• Nucleus: Contains DNA (genetic material).
• Mitochondria: Produces ATP (energy).
• Cell Membrane: Regulates substance passage.
• Ribosomes: Synthesize proteins.
• Chloroplasts: Site of photosynthesis (in plant cells).

Microscope Fundamentals

Basic parts include the eyepiece, objective lenses, stage, coarse focus knob, and fine focus knob.

Mitosis (Cell Division)

The stages are summarized by the acronym PMAT:

1. Prophase
2. Metaphase
3. Anaphase
4. Telophase

Uncontrolled cell growth is known as cancer.

Specialized Cells and Roles

• Red Blood Cells (RBCs): Oxygen transport.
• White Blood Cells (WBCs): Immunity and defense.
• Muscle Cells: Movement.
• Nerve Cells: Signal transmission.
• Skin Cells: Protection.

Levels of Biological Organization

Cell → Tissue → Organ → System → Organism

Major Human Body Systems

• Digestive System: Breaks down food for nutrient absorption.
• Respiratory System: Facilitates gas exchange (oxygen and carbon dioxide) in the lungs.
• Circulatory System: Transports oxygen and nutrients via the blood.

Plant Tissues and Function

• Dermal Tissue: Protection.
• Vascular Tissue: Transport (xylem for water, phloem for sugars).
• Ground Tissue: Photosynthesis and storage.

Leaf Gas Exchange

Gases are exchanged with the environment primarily via specialized pores called stomata.

Climate Change Science and Evidence

Defining Weather vs. Climate

• Weather: Short-term atmospheric conditions (e.g., daily temperature, precipitation).
• Climate: Long-term patterns and averages of weather conditions.

Components of the Climate System

The system involves interactions between four major spheres:

• Atmosphere (air)
• Hydrosphere (water)
• Lithosphere (land/rock)
• Biosphere (life)

The Greenhouse Effect

This is a natural process that warms the Earth. Anthropogenic (human-caused) intensification is driven primarily by increased concentrations of greenhouse gases like Carbon Dioxide (CO₂) and Methane (CH₄).

Evidence of Climate Change

• Melting ice caps and glaciers
• Rising global temperatures
• Increased frequency of wildfires
• Record extreme weather events

Climate Study Tools

• Satellites and remote sensing
• Complex climate models
• Ice cores (historical atmospheric data)
• Tree rings (paleoclimatology)