Science Essentials: Sun, Matter, Physics

The Sun: Structure and Activity

Galileo's Solar Observations

Galileo Galilei was among the first scientists to study the Sun in detail (circa 1610).

Sun's Chemical Makeup

The Sun's composition is primarily Helium & Hydrogen.

Inside the Sun

Solar Atmosphere Layers

• Photosphere
• Chromosphere
• Corona

Solar Interior Zones

• Core
• Radiative Zone
• Convective Zone

How the Sun Produces Energy

Solar energy is produced by nuclear fusion in the core region, converting hydrogen into helium. This process is the source of the Sun's energy.

The energy output is approximately 9 × 10¹⁰ megatons of TNT per second.

Understanding Solar Wind

Solar Wind is solar material flowing into interplanetary space. The Sun's atmosphere is expanding radially outwards in all directions. Solar wind velocity typically ranges from 400 to 700 km/s.

What Are Sunspots?

Sunspots are temporary phenomena on the Sun's photosphere that appear visibly as dark spots compared to surrounding regions because of their reduced temperature relative to the surrounding photosphere.

Sunspot lifetime: several days (typically less than 3 weeks). Temperature: 4,000 K (The surrounding Photosphere is approximately 6,000 K).

The 11-Year Solar Cycle

The Solar Cycle is the nearly periodic 11-year change in solar activity, including changes in the number of sunspots, flares, and other related phenomena.

Measuring Sunspots: Wolf Number

The Sunspot Number, also known as the Wolf Number, is a measure of the number of sunspots and groups of sunspots present on the solar photosphere.

Solar Flares Explained

Flares are bursting phenomena associated with sunspots.

Earth's Atmosphere and Climate

Weather vs. Climate Defined

Weather is the state of the atmosphere at any given place and time.

Climate is the average (mean) of weather parameters over a long period of time.

Global Warming Explained

Global Warming refers to the general rise in the average temperature of the Earth's climate system and its related effects.

Fundamental Science Concepts

Structure of Matter Basics

Matter is everything that fills space...

Evolution of Atomic Models

1. Dalton: Billiard Ball Model
2. Thomson: Electron - Plum Pudding Model
3. Rutherford: Proton - Planetary Model
4. Bohr: Planetary Model with arrangement of electrons
5. Schrodinger: Cloud Model
6. Chadwick: Associated with the Neutron

Key Definitions in Chemistry

Defining Atom, Element, Molecule

Atom: The basic or fundamental constituent of matter.

Element: A species of atoms having the same number of protons in their atomic nuclei.

Molecule: An electrically neutral group of two or more atoms held together by chemical bonds.

Compound and Nucleosynthesis

Compound: An electrically neutral group of two or more atoms of different elements held together by chemical bonds.

Nucleosynthesis: The process by which elements are formed.

Ions and Isotopes

Ion: An atom or molecule in which the number of electrons is not equal to the number of protons (resulting in a net electrical charge).

Note: Extracting electrons from atoms can lead to the formation of plasma.

Isotope: Atoms of the same element (same number of protons) that have a different number of neutrons.