General Science: Basic Concepts

Science is the systematic study of the structure and behavior of the physical and natural world through observation and experimentation.

Branches of Science :

1. Physical Sciences:

   • Physics: Study of matter and energy and their interactions (gravity, light, time).

   • Chemistry: Focuses on the composition, properties, reactions, and structure of matter.

   • Astronomy: Studies the universe beyond Earth’s atmosphere.

2. Earth Sciences:

   • Geology: Examines the origin, history, and structure of the Earth, including physical, chemical, and biological changes.

   • Oceanography: Exploration and study of oceanic processes.

   • Paleontology: Studies prehistoric forms of life.

   • Meteorology: Investigates atmospheric phenomena, including weather and climate.

3. Life Sciences (Biology):

   • Botany: The study of plants.

   • Zoology: Covers animal life.

   • Genetics: Focuses on heredity.

   • Medicine: The science of diagnosing, treating, and preventing illness, diseases, and injuries.

Scientific Method

• a logical process employed by scientists to gain knowledge and explain various natural phenomena.

• A phenomenon is defined as something observed through the senses, while a scientifically validated observation is referred to as a fact.

1. Identify the Problem: Clearly articulate the issue at hand. Questions typically stem from unusual observations, leading to a specific, measurable, and attainable problem identification.

2. Gather Relevant Information: Collect information related to the identified problem by reflecting on past experiences, interviewing knowledgeable individuals, and researching in libraries and research institutions.

3. Formulate a Hypothesis: Based on the gathered information, create an educated guess or hypothesis.

4. Test the Hypothesis: Conduct experiments to test the validity of the hypothesis.

Energy

The term energy originates from the Greek word energeia (with en meaning "in" and ergon meaning "work"). Energy is the capacity to perform work or to apply force to an object, enabling it to move.

Forms of Energy

1. Mechanical Energy

   • Kinetic Energy: Energy associated with the motion of an object.

   • Potential Energy: Energy held by an object due to its position or state.

2. Internal Energy or Thermal Energy: Total energy resulting from the attractive and repulsive forces among all particles or molecules in a substance.

3. Heat Energy: Energy that transfers from one body to another due to a temperature difference, always moving from the warmer body to the cooler body.

4. Electrical Energy: Energy generated by the flow of electrons through conductors, such as copper and aluminum wires.

5. Chemical Energy: Energy stored within matter due to the forces of attraction and the arrangement of subatomic particles in atoms and atoms in molecules.

Methods of Heat Transfer

1. Conduction: This is the process where heat is transferred through direct contact of molecules within a material. When a part of the material is heated, molecules move faster and transfer heat to adjacent molecules until the heat is evenly distributed. Conductors allow heat to pass easily, whereas insulators do not.

2. Convection: Heat is transferred through the movement of liquids or gases, creating convection currents due to temperature differences.

3. Radiation} This method involves the transfer of heat through emission in all directions, such as heat from the sun or other hot objects.

Energy Resources

a. Fossil Fuels

1. Coal: Formed from ancient vegetation buried underwater.

2. Petroleum: A liquid mix of hydrocarbons, both gaseous and liquid.

3. Natural Gas: Composed of carbon and hydrogen, mostly methane.

b. Hydroelectric Power: Electricity generated using water turbines driven by flowing water.

c. Geothermal Energy: Thermal energy sourced from beneath the Earth's surface, harnessing steam.

d. Wind Energy: Energy captured through windmills.

e. Solar Energy: Energy obtained from sunlight, converted to electricity using solar cells or photovoltaic cells.

Formation of Solar System

• As matter condensed in the Milky Way, a star formed where the Sun is now located. This star ignited and exploded, dispersing matter. Gravitational forces gathered this matter into planets and the asteroid belt, which contains remnants that couldn't form into a planet due to Jupiter's gravity. Collisions among early planets may have led to the creation of larger planets and moons. Meanwhile, a smaller star formed at the explosion's center, allowing our Sun to begin fusion again.

Earth’s Structure

The Earth is composed of several distinct layers, with the three primary layers being the core, mantle, and crust.

• The core is the innermost layer of the Earth.

• The mantle lies between the core and the crust.

• The crust is the outermost layer of the Earth.

Additionally, the Earth is enveloped by the atmosphere.

Currently, it is not feasible to directly observe the inside of the Earth due to technological limitations. As a result, various research methods have been employed to determine the materials that compose the Earth, the different layers that exist, and their impacts on the Earth’s surface. This field of study is known as seismology.

The Core

The innermost layer of the Earth is the core, located approximately 1,800 miles (2,900 km) beneath the Earth's surface. This dense sphere is primarily composed of iron and nickel, and it is subdivided into two parts: the inner core and the outer core.

• The Inner Core: The Earth's center, which is solid and about 780 miles (1,250 km) thick. Despite temperatures soaring to 6,700°F (3,700°C), the immense pressure within prevents it from melting.

• The Outer Core: This layer is molten due to extreme heat and measures around 1,370 miles (2,200 km) thick. The rotation of the Earth causes the outer core to circulate around the inner core, which generates the planet's magnetic field.

The Mantle

Sitting above the core is the mantle, beginning roughly 6 miles (10 km) below the oceanic crust and about 19 miles (30 km) beneath the continental crust. The mantle is approximately 1,800 miles (2,900 km) thick and comprises nearly 80 percent of the Earth's volume, divided into the inner mantle and the outer mantle.

The Crust

The crust is the outermost layer of the Earth, forming the hard shell on which we live. It is significantly thinner compared to the mantle and floats on the denser, more malleable mantle beneath. The crust consists of solid materials, divided into two types:

• Oceanic Crust: Generally 4-7 miles (6-11 km) thick, composed of heavier rocks like basalt.

Plate Tectonics

The Earth's crust consists of moving tectonic plates, including nine large and twelve smaller ones, which aid in explaining phenomena like continental drift, volcanic eruptions, and mountain formation.

• Continental Drift: Continents have slowly drifted apart over millions of years, visible in how the east coast of the Americas aligns with the west coast of Europe and Africa.

• Diverging Plates: Plates pull apart at mid-ocean ridges, allowing magma to surface and form new oceanic plates. These ridges, like the Mid-Atlantic Ridge, are active volcanic and seismic zones.

• Converging Plates: When plates collide, one can subduct beneath the other, forming ocean trenches and creating mountain ranges due to crumpling of the crust. This process often leads to volcanic activity and earthquakes.

• Seafloor Spreading: Volcanic activity under the ocean helps create ridges that split continents.

• Diastrophism: The process involving movements of the Earth's crust, leading to portions being pushed up, pushed down, or forced sideways.

1. Folding: This process occurs when sideward forces act on rocks, deforming them into wavelike folds after tilting, bending, or wrinkling.

2. Faulting: This involves the sliding or movement of rock layers over one another along a break or fracture, which can occur either vertically or horizontally.

Rocks

Rocks are categorized into three types according to their formation process:

1. Igneous Rocks

• Formed when molten rock (magma) within the Earth cools and solidifies.

• Two types:

  • Intrusive Igneous Rocks: Solidify beneath the Earth's surface.

  • Extrusive Igneous Rocks: Solidify at the surface.

• Examples: Granite, basalt, obsidian.

2. Sedimentary Rocks

• Formed when sediment, which includes pieces of rock and materials like shells and sand, compacts together.

• Formation can take millions of years.

• Most rocks visible on the surface are sedimentary.

• Examples: Limestone, sandstone, shale.

3. Metamorphic Rocks

• Formed from the transformation of sedimentary or igneous rocks due to heat, pressure, or both.

• Typically formed deep within the Earth, often during mountain-building processes.

• Examples: Schist, marble, slate.

The Rock Cycle

The three principal types of rocks—igneous, sedimentary, and metamorphic—are interconnected through various natural processes:

• Igneous rocks originate from the cooling and crystallization of hot molten lava and magma.

• They undergo weathering and erosion, producing sediments.

• These sediments accumulate and undergo lithification through compaction and cementation, forming sedimentary rocks.

• When sedimentary rocks are buried deeper by new layers, they experience heat and pressure, transforming into metamorphic rocks.

• With additional burial and heating, metamorphic rocks can melt, resulting in partially molten rocks known as migmatite.

• Continued melting leads to the formation of magma, which either cools and crystallizes into plutonic igneous rock or erupts onto the surface as lava, ultimately cooling into volcanic igneous rock.

Complications in the Rock Cycle

• Weathering can occur in sedimentary, metamorphic, and igneous rocks.

• Metamorphism can affect igneous rocks and multiple cycles of metamorphism of metamorphic rocks.