Comprehensive Engineering Science: Chemistry, Mechanics, and Thermodynamics of Heat and Steam

Foundations of Science and the Scientific Method

• Branches of Science: Science is organized into four major comprehensive branches, each encompassing distinct domains of inquiry and practical application:

  • Natural Sciences: The systematic study of the physical universe, natural phenomena, and living organisms. It subdivides into:

  • Physical Sciences:

    • Chemistry: The study of matter, its properties, composition, structure, and the transformations it undergoes.

    • Physics: The study of matter, energy, motion, and fundamental forces.

    • Astronomy: The chemistry and physics of celestial bodies, space, and the universe.

  • Life Sciences:

    • Biology: The study of living organisms and vital life processes.

    • Ecology: The study of organisms and their interactions with their surrounding environment.

    • Genetics: The study of heredity and the variation of inherited characteristics.

    • Zoology: The biological study of animals.

    • Botany: The biological study of plants.

  • Earth Science:

    • Geology: The study of the Earth's physical structure, substance, history, and internal processes.

    • Oceanography: The physical, chemical, and biological exploration of the ocean.

    • Meteorology: The atmospheric science concerned with weather processes and forecasting.

    • Paleontology: The study of prehistoric life through fossil remains.

  • Applied Sciences: The practical translation and implementation of scientific knowledge into real-world applications and technological systems:

  • Engineering: Subdivided into Mechanical Engineering, Electrical Engineering, Civil Engineering, and Computer Science.

  • Health Sciences: Encompasses Medicine, Dentistry, and Pharmacy.

  • Agriculture: The science of cultivating plants and livestock for human use.

  • Formal Sciences: Theoretical disciplines focused on abstract symbolic systems, rule sets, and formal frameworks:

  • Mathematics: The study of numbers, quantities, space, and structural relationships.

  • Statistics: The collection, analysis, interpretation, and presentation of quantitative data.

  • Logic: The systematic study of valid reasoning, inference, and argument structure.

  • Social Sciences: The empirical study of human societies, interpersonal relationships, and societal behaviors:

  • Sociology: The study of social institutions, development, and social structures.

  • Psychology: The scientific inquiry into mental functions, human cognition, and behaviors.

  • Economics: The production, distribution, and consumption of goods, resources, and services.

  • Law: The formal systems of rules, jurisprudence, and behavioral standards enacted by societies.

  • Political Science: The study of statecraft, governance systems, power dynamics, and political actions.

• The Scientific Method:

  • A systematic methodology comprised of standardized procedural steps for the reliable pursuit and validation of knowledge.

  • Core Stages:

  • Recognition and systematic formulation of a scientific problem or question.

  • Empirical data collection executed through direct observation and structured experimentation.

  • Formulation of an explanatory, testable hypothesis.

  • Experimental testing, critical evaluation, and refinement or rejection of the hypothesis based on reproducible observations.

Atomic Theory and Structure of Matter

• Fundamental Definitions of Matter and Elements:

  • Matter: Any entity or substance that possesses mass (weight) and occupies space by having a measurable volume.

  • Chemical Element: A pure substance that cannot be broken down, divided, or transformed into a simpler form of matter through chemical means.

  • Atom: The smallest constituent unit of a chemical element that retains the distinct chemical properties and identity of that element. Atoms can exist in isolation or bound together in chemical combinations with other elements.

• Subatomic Structure:

  • Atoms are not continuous solid spheres; they are composed mostly of empty space surrounding a central, dense mass.

  • Nucleus: The extremely dense, positively charged region at the center of an atom consisting of two primary subatomic nucleons:

  • Protons ($\text{P}$): Subatomic particles possessing a positive electric charge ($+$).

  • Neutrons ($\text{N}$): Subatomic particles possessing no electrical charge (neutral charge).

  • Electron Shells (Orbits or Energy Levels):

  • Electrons ($\text{E}$): Negatively charged ($-$) particles that orbit within the probabilistic electron cloud surrounding the atomic nucleus.

  • Electrons populate distinct, quantized spatial regions known as energy levels, shells, or orbits. The boundary of these outermost orbits defines the effective physical size and atomic radius of the atom.

  • Valence Electrons: Electrons located in the outermost shell that dictate chemical reactivity, bonding characteristics, and electrical conductivity.

• Comparative Atomic Models:

  • Hydrogen ($\text{H}$): The simplest and lightest atomic architecture, consisting of $1$ Proton, $0$ Neutrons, and $1$ Electron located in a single shell.

  • Oxygen ($\text{O}$): Possesses $8$ Protons, $8$ Neutrons, and $8$ Electrons ($2$ inner shell electrons and $6$ outer valence electrons).

  • Copper ($\text{Cu}$): A transitional metallic atom with $29$ Protons, $35$ Neutrons, and $29$ Electrons arranged across four shells ($2, 8, 18, 1$), featuring a single, weakly held outermost valence electron that provides high electrical and thermal conductivity.

The Periodic Table of Elements

• Mendeleev's Periodic Architecture:

  • Created by Russian chemist Dmitri Mendeleev to organize elements according to recurring, periodic trends in their physical and chemical behaviors.

  • Organizes chemical elements into vertical columns designated as families or groups, and horizontal rows termed periods, aligning elements with analogous valence structures and reaction properties.

• Modern Periodic Organization:

  • The modern periodic table contains $118$ confirmed chemical elements arranged in ascending order by atomic number (the number of protons residing in the nucleus).

  • Categorical Division of Elements:

  • Metals: Good electrical and thermal conductors, lustrous, malleable, and ductile; they tend to lose electrons in chemical reactions.

  • Nonmetals: Poor thermal and electrical conductors, non-malleable, brittle in solid forms; they tend to gain or share electrons.

  • Metalloids: Elements displaying intermediate properties bridging typical metals and typical nonmetals (e.g., Silicon, Boron, Germanium, Arsenic, Antimony, Tellurium).

  • Subcategories: Alkali metals, Alkaline-earth metals, Transition metals, Lanthanoids, Actinoids, Other metals, Halogens, and Noble gases.

• Element Block Anatomy:

  • Each individual element block encodes precise chemical and physical data:

  • Atomic Number: Total number of nuclear protons (e.g., $7$ for Nitrogen).

  • Symbol: One- or two-letter standard abbreviation (e.g., $\text{N}$).

  • Element Name: Full IUPAC designation (e.g., Nitrogen).

  • Atomic Weight / Average Atomic Mass: Weighted average mass expressed in atomic mass units (e.g., Nitrogen: $[14.00643, 14.00728]$).

  • Electron Configuration: Electronic orbital occupancy (e.g., Nitrogen: $[\text{He}]2s^2 2p^3$).

  • Physical State at $20^\circ\text{C}$ ($68^\circ\text{F}$): State of matter under standard ambient conditions (e.g., gas for Nitrogen).

  • Crystal Structure: Solid-phase geometric lattice geometry (e.g., hexagonal for Nitrogen).

  • Acid-Base Properties of Higher-Valence Oxides: Classification of oxide acidity (e.g., strongly acidic for Nitrogen).

• Complete Listing of Elements by Atomic Number ($1$ to $118$):

  • $1$: Hydrogen ($\text{H}$), $2$: Helium ($\text{He}$), $3$: Lithium ($\text{Li}$), $4$: Beryllium ($\text{Be}$), $5$: Boron ($\text{B}$), $6$: Carbon ($\text{C}$), $7$: Nitrogen ($\text{N}$), $8$: Oxygen ($\text{O}$), $9$: Fluorine ($\text{F}$), $10$: Neon ($\text{Ne}$)

  • $11$: Sodium ($\text{Na}$), $12$: Magnesium ($\text{Mg}$), $13$: Aluminum ($\text{Al}$), $14$: Silicon ($\text{Si}$), $15$: Phosphorus ($\text{P}$), $16$: Sulfur ($\text{S}$), $17$: Chlorine ($\text{Cl}$), $18$: Argon ($\text{Ar}$), $19$: Potassium ($\text{K}$), $20$: Calcium ($\text{Ca}$)

  • $21$: Scandium ($\text{Sc}$), $22$: Titanium ($\text{Ti}$), $23$: Vanadium ($\text{V}$), $24$: Chromium ($\text{Cr}$), $25$: Manganese ($\text{Mn}$), $26$: Iron ($\text{Fe}$), $27$: Cobalt ($\text{Co}$), $28$: Nickel ($\text{Ni}$), $29$: Copper ($\text{Cu}$), $30$: Zinc ($\text{Zn}$)

  • $31$: Gallium ($\text{Ga}$), $32$: Germanium ($\text{Ge}$), $33$: Arsenic ($\text{As}$), $34$: Selenium ($\text{Se}$), $35$: Bromine ($\text{Br}$), $36$: Krypton ($\text{Kr}$), $37$: Rubidium ($\text{Rb}$), $38$: Strontium ($\text{Sr}$), $39$: Yttrium ($\text{Y}$), $40$: Zirconium ($\text{Zr}$)

  • $41$: Niobium ($\text{Nb}$), $42$: Molybdenum ($\text{Mo}$), $43$: Technetium ($\text{Tc}$), $44$: Ruthenium ($\text{Ru}$), $45$: Rhodium ($\text{Rh}$), $46$: Palladium ($\text{Pd}$), $47$: Silver ($\text{Ag}$), $48$: Cadmium ($\text{Cd}$), $49$: Indium ($\text{In}$), $50$: Tin ($\text{Sn}$)

  • $51$: Antimony ($\text{Sb}$), $52$: Tellurium ($\text{Te}$), $53$: Iodine ($\text{I}$), $54$: Xenon ($\text{Xe}$), $55$: Cesium ($\text{Cs}$), $56$: Barium ($\text{Ba}$), $57$: Lanthanum ($\text{La}$), $58$: Cerium ($\text{Ce}$), $59$: Praseodymium ($\text{Pr}$), $60$: Neodymium ($\text{Nd}$)

  • $61$: Promethium ($\text{Pm}$), $62$: Samarium ($\text{Sm}$), $63$: Europium ($\text{Eu}$), $64$: Gadolinium ($\text{Gd}$), $65$: Terbium ($\text{Tb}$), $66$: Dysprosium ($\text{Dy}$), $67$: Holmium ($\text{Ho}$), $68$: Erbium ($\text{Er}$), $69$: Thulium ($\text{Tm}$), $70$: Ytterbium ($\text{Yb}$)

  • $71$: Lutetium ($\text{Lu}$), $72$: Hafnium ($\text{Hf}$), $73$: Tantalum ($\text{Ta}$), $74$: Tungsten ($\text{W}$), $75$: Rhenium ($\text{Re}$), $76$: Osmium ($\text{Os}$), $77$: Iridium ($\text{Ir}$), $78$: Platinum ($\text{Pt}$), $79$: Gold ($\text{Au}$), $80$: Mercury ($\text{Hg}$)

  • $81$: Thallium ($\text{Tl}$), $82$: Lead ($\text{Pb}$), $83$: Bismuth ($\text{Bi}$), $84$: Polonium ($\text{Po}$), $85$: Astatine ($\text{At}$), $86$: Radon ($\text{Rn}$), $87$: Francium ($\text{Fr}$), $88$: Radium ($\text{Ra}$), $89$: Actinium ($\text{Ac}$), $90$: Thorium ($\text{Th}$)

  • $91$: Protactinium ($\text{Pa}$), $92$: Uranium ($\text{U}$), $93$: Neptunium ($\text{Np}$), $94$: Plutonium ($\text{Pu}$), $95$: Americium ($\text{Am}$), $96$: Curium ($\text{Cm}$), $97$: Berkelium ($\text{Bk}$), $98$: Californium ($\text{Cf}$), $99$: Einsteinium ($\text{Es}$), $100$: Fermium ($\text{Fm}$)

  • $101$: Mendelevium ($\text{Md}$), $102$: Nobelium ($\text{No}$), $103$: Lawrencium ($\text{Lr}$), $104$: Rutherfordium ($\text{Rf}$), $105$: Dubnium ($\text{Db}$), $106$: Seaborgium ($\text{Sg}$), $107$: Bohrium ($\text{Bh}$), $108$: Hassium ($\text{Hs}$), $109$: Meitnerium ($\text{Mt}$), $110$: Darmstadtium ($\text{Ds}$)

  • $111$: Roentgenium ($\text{Rg}$), $112$: Copernicium ($\text{Cn}$), $113$: Nihonium ($\text{Nh}$), $114$: Flerovium ($\text{Fl}$), $115$: Moscovium ($\text{Mc}$), $116$: Livermorium ($\text{Lv}$), $117$: Tennessine ($\text{Ts}$), $118$: Oganesson ($\text{Og}$)

• Elemental Abundance Distribution Across Earth Systems:

  • Whole Earth: Iron ($32\%$), Oxygen ($30\%$), Silicon ($15\%$), Magnesium ($14\%$), Sulfur ($3\%$), Nickel ($2\%$), Calcium ($2\%$), Aluminum ($1\%$), Other elements ($<1\%$).

  • Earth's Crust: Oxygen ($46\%$), Silicon ($28\%$), Aluminum ($8\%$), Iron ($6\%$), Magnesium ($4\%$), Other ($3.2\%$), Calcium ($2.5\%$), Potassium ($2.3\%$).

  • Earth's Atmosphere: Nitrogen ($78\%$), Oxygen ($21\%$), Argon ($1\%$), Water vapor ($0.4\%$), Carbon dioxide ($0.04\%$), Other ($0.04\%$), Neon ($0.0018\%$).

  • Earth's Oceans: Oxygen ($86\%$), Hydrogen ($10.8\%$), Chlorine ($1.857\%$), Sodium ($1.075\%$), Magnesium ($0.127\%$), Sulfur ($0.088\%$), Calcium ($0.04\%$), Potassium ($0.038\%$), Other ($0.014\%$ to $3.2\%$).

• Quantitative Estimates of Earth's Abundant Elements:

Chemical Bonding and Molecular Interactions

• Primary Types of Chemical Bonds:

  • Covalent Bonds: Formed when two nonmetal atoms achieve stable valence shells by sharing one or more pairs of valence electrons (e.g., diatomic oxygen $O_2$, and methane $CH_4$, where carbon shares electrons with four hydrogen atoms).

  • Ionic Bonds: Formed through electrostatic attraction following the complete transfer of one or more electrons from a metallic atom to a nonmetallic atom. The metal atom loses electrons to become a positively charged cation, while the nonmetal gains electrons to become a negatively charged anion (e.g., Sodium Chloride, $NaCl$).

  • Metallic Bonds: The binding force characterizing metals, consisting of an array of fixed positive metal cations immersed within a delocalized, freely moving cloud of conducting electrons (e.g., solid copper $\text{Cu}^{2+}$ lattice).

  • Hydrogen Bonds: A weak electrostatic intermolecular attraction occurring when a hydrogen atom covalently bound to a highly electronegative atom (such as oxygen) experiences attraction toward an unshared pair of electrons on an adjacent electronegative atom.

• Molecular Dynamics and Capillary Behavior of Water:

  • A water molecule ($H_2O$) consists of two hydrogen atoms covalently bound to an oxygen atom in a bent geometric configuration.

  • This bent geometry causes charge polarization: the oxygen atom retains a partial negative charge ($\delta^-$), while the hydrogen atoms exhibit a partial positive charge ($\delta^+$).

  • As a result of this permanent dipole, adjacent water molecules form cohesive hydrogen-bonded networks.

  • When water comes into contact with a polar surface such as glass, adhesive electrostatic forces between the edge water molecules and the silicate structure of the glass exceed internal cohesion, causing water to exhibit capillary action and climb upward along the walls of narrow glass tubes.

Classification and Properties of Matter

• Classification of Mixtures:

  • Solutions: Homogeneous mixtures in which solute particles are dissolved down to the molecular or ionic level. Small particles cannot be visually identified, do not settle over time, and cannot be separated by standard mechanical filtration (e.g., sugar thoroughly dissolved in water).

  • Suspensions: Heterogeneous mixtures containing large, visible insoluble particles dispersed throughout a liquid medium. The particles remain suspended only temporarily and will settle out due to gravity or can be removed by filtration (e.g., oil mixed with water, sand in water).

  • Colloids: Heterogeneous mixtures containing intermediate-sized particles that remain permanently dispersed throughout a continuous medium. The particles do not settle out and cannot be separated by mechanical filtration, but they scatter light, giving the substance a cloudy or opaque visual appearance (e.g., milk).

• Four States (Phases) of Matter:

  • Solid: State characterized by low molecular kinetic energy where molecules vibrate in fixed positions. Possesses a fixed shape and a fixed volume (e.g., water ice at or below $32^\circ\text{F}$ / $0^\circ\text{C}$).

  • Liquid: State where increased thermal energy allows molecules to slide past one another while remaining bound by intermolecular cohesion. Takes the shape of its container, forms a horizontal free surface, and maintains a fixed volume (e.g., liquid water between $33^\circ\text{F}$ and $211^\circ\text{F}$ / $0.56^\circ\text{C}$ and $99^\circ\text{C}$).

  • Gas / Vapor: High-energy state where molecular kinetic energy completely overcomes intermolecular attractions. Molecules move freely in all directions, expanding to fill the entire shape and volume of any enclosing container (e.g., steam at and above $212^\circ\text{F}$ / $100^\circ\text{F}$).

  • Plasma: An ionized gas consisting of unbound positive ions and free electrons under high energy or electrical potential. Found in natural phenomena such as lightning strikes and industrial operations.

• Industrial Applications and Hazards of Plasma:

  • Plasma Arc Cutting and Welding: Utilized in the piping trades to cut, bevel, and join metals using high-velocity jets of ionized gas reaching temperatures capable of melting structural alloys instantly.

  • Electric Arc Flash: An electrical explosion that ionizes surrounding air into plasma, generating an explosive fireball with thermal radiation reaching temperatures hotter than the surface of the sun.

Physical and Chemical Properties

• Definitions of Substance Properties:

  • Physical Property: A measurable or observable characteristic of matter that does not alter the chemical identity or composition of the substance during observation. Includes state of matter, density, specific gravity, color, odor, taste, melting and boiling points, and electrical/thermal conductivity.

  • Chemical Property: A characteristic observed during a chemical reaction that results in a change to the fundamental chemical composition of the substance. Includes toxicity, acidity, flammability, ignition temperature, corrosivity, and heating value.

• Standard Properties of Water ($H_2O$):

  • Chemical Formula: $H_2O$

  • Physical Properties:

  • Color: Colorless

  • Taste: Tasteless

  • Odor: Odorless

  • Density at $32.2^\circ\text{F}$ ($0.1^\circ\text{C}$): $62.418\,\text{lb/ft}^3$

  • Specific Gravity, Gas: $1$

  • Specific Gravity, Liquid at $39.2^\circ\text{F}$ ($4^\circ\text{C}$): $1$

  • Specific Gravity, Solid at $32^\circ\text{F}$ ($0^\circ\text{C}$): $0.9168$

  • Boiling Point: $212^\circ\text{F}$ ($100^\circ\text{C}$)

  • Melting Point: $32^\circ\text{F}$ ($0^\circ\text{C}$)

  • Chemical Properties:

  • Toxicity: Non-toxic

  • Corrosivity: Highly corrosive (promotes oxidation in piping and metals)

  • Heating Value: No heating value (water is non-combustible; it is an end product of hydrocarbon combustion)

Fundamental Units of Measurement and Conversions

• Fundamental Systems of Units:

• Mass and Weight Conversions:

  • Metric to US/Imperial Mass Units:

  • $1\,\text{milligram (mg)} = 0.0154\,\text{grain}$

  • $1\,\text{gram (g)} = 1{,}000\,\text{mg} = 0.0353\,\text{oz}$

  • $1\,\text{kilogram (kg)} = 1{,}000\,\text{g} = 2.2046\,\text{lb}$

  • $1\,\text{tonne (t)} = 1{,}000\,\text{kg} = 1.1023\,\text{short ton (US)}$

  • $1\,\text{tonne (t)} = 1{,}000\,\text{kg} = 0.9842\,\text{long ton (UK)}$

  • US/Imperial to Metric Mass Units:

  • $1\,\text{ounce (oz)} = 437.5\,\text{grain} = 28.35\,\text{g}$

  • $1\,\text{pound (lb)} = 16\,\text{oz} = 0.4536\,\text{kg}$

  • $1\,\text{stone} = 14\,\text{lb} = 6.3503\,\text{kg}$

  • $1\,\text{hundredweight} = 112\,\text{lb} = 50.802\,\text{kg}$

  • $1\,\text{short ton (US)} = 2{,}000\,\text{lb} = 0.9072\,\text{t}$

  • $1\,\text{long ton (UK)} = 2{,}240\,\text{lb} = 1.0160\,\text{t}$

• Volume and Capacity Conversions:

  • Metric Volume Units:

  • $1\,\text{cm}^3 = 0.0610\,\text{in}^3$

  • $1\,\text{dm}^3 = 1{,}000\,\text{cm}^3 = 0.0353\,\text{ft}^3$

  • $1\,\text{m}^3 = 1{,}000\,\text{dm}^3 = 1.03080\,\text{yd}^3$

  • $1\,\text{liter (l)} = 1\,\text{dm}^3 = 2.113\,\text{US pt} = 1.7598\,\text{UK pt}$

  • US/Imperial Volume Units:

  • $1\,\text{in}^3 = 16.387\,\text{cm}^3$

  • $1\,\text{ft}^3 = 0.02832\,\text{m}^3$

  • $1\,\text{US fluid ounce} = 1.0408\,\text{UK fl oz} = 29.574\,\text{ml}$

  • $1\,\text{US pint (16 fl oz)} = 0.8327\,\text{UK pt} = 0.4732\,\text{l}$

  • $1\,\text{US gallon (231 in}^3) = 0.8327\,\text{UK gal} = 3.7854\,\text{l}$

Mechanics of Mass, Weight, Density, and Specific Gravity

• Mass versus Weight Principles:

• Gravitational Field Variation:

  • An object with an invariant mass equivalent to a weight of $200\,\text{lb}$ on Earth displays differing weights across varied gravitational settings:

  • Earth Surface: $W = 200\,\text{lb}$

  • Moon Surface: $W = 33.7\,\text{lb}$ (approx. $1/6$ of Earth gravity)

  • Deep Space: $W = 0\,\text{lb}$ (weightless environment)

• Density and the Density Triangle:

  • Density ($D$): The mass or weight per unit volume of a given substance:     $D = \frac{W}{V}$

  • Volume ($V$): The physical space occupied by a substance:     $V = \frac{W}{D}$

  • Weight ($W$): Total mass or gravitational force of the matter:     $W = D \times V$

  • Standard Units:

  • Density: $\text{lb/ft}^3$, $\text{g/cm}^3$, $\text{kg/m}^3$

  • Volume: $\text{ft}^3$, $\text{in}^3$, $\text{cm}^3$, $\text{mL}$

  • Weight: $\text{lb}$, $\text{g}$, $\text{kg}$

• Density of Pure Water:

  • A cubic block measuring $1\,\text{ft} \times 1\,\text{ft} \times 1\,\text{ft}$ has a unit volume of $1\,\text{ft}^3$ or $1{,}728\,\text{in}^3$ ($12\,\text{in} \times 12\,\text{in} \times 12\,\text{in}$).

  • Pure water occupying $1\,\text{ft}^3$ weighs exactly $62.4\,\text{lb}$.

  • The volumetric mass density of pure water is defined as $62.4\,\text{lb/ft}^3$ ($1{,}000\,\text{kg/m}^3$).

• Step-by-Step Worked Calculation: Density of Solid Steel:

  • Problem: Calculate the density of a solid cylindrical steel bar with a diameter of $3\,\text{in}$, length of $10\,\text{in}$, and measured weight of $20.04\,\text{lb}$.

  • Step 1: Calculate Cross-Sectional Area ($A$):     $\text{Radius } (R) = \frac{3\,\text{in}}{2} = 1.5\,\text{in}$     $A = \pi \times R^2 = 3.1416 \times (1.5\,\text{in})^2 = 3.1416 \times 2.25\,\text{in}^2 = 7.0686\,\text{in}^2$

  • Step 2: Calculate Cylindrical Volume ($V$):     $V = A \times \text{Length} = 7.0686\,\text{in}^2 \times 10\,\text{in} = 70.69\,\text{in}^3$

  • Step 3: Calculate Density in Pounds per Cubic Inch:     $D = \frac{W}{V} = \frac{20.04\,\text{lb}}{70.69\,\text{in}^3} = 0.283\,\text{lb/in}^3$

  • Step 4: Convert Density to Standard Engineering Units ($\text{lb/ft}^3$):     $D = 0.283\,\text{lb/in}^3 \times 1{,}728\,\text{in}^3/\text{ft}^3 = 489\,\text{lb/ft}^3$

• Specific Gravity ($\text{SG}$):

  • The dimensionless ratio of the density of a substance to the density of a standard reference substance (pure water for liquids and solids):     $\text{SG} = \frac{\text{Density of Substance}}{\text{Density of Reference (Water)}}$

  • Calculation for Steel:     $\text{SG}_{\text{steel}} = \frac{489\,\text{lb/ft}^3}{62.4\,\text{lb/ft}^3} = 7.82$

  • Buoyancy and Immersion Dynamics:

  • Substances with $\text{SG} > 1.0$ sink in water; substances with $\text{SG} < 1.0$ float on water.

  • Copper has a density of $549\,\text{lb/ft}^3$ ($9{,}000\,\text{kg/m}^3$) and $\text{SG} = 8.79$. Since $8.79 > 1.0$, copper sinks in water.

  • Liquid mercury has a density of $845\,\text{lb/ft}^3$ to $854\,\text{lb/ft}^3$ ($13{,}600\,\text{kg/m}^3$) and $\text{SG} = 13.59$. Because $8.79 < 13.59$, copper floats on liquid mercury.

  • Gaseous substances like methane ($CH_4$) are compared against air ($\text{SG} = 0.0013$ relative to water) to evaluate whether they rise or accumulate at floor level.

• Comparative Specific Weight and Specific Gravity of Materials:

Thermal Energy and Temperature Measurement

• Nature of Thermal Energy:

  • Heat is a form of thermal energy caused by the motion of particles within matter.

  • When heat is added to a substance, the kinetic energy and vibrational or translational velocity of its molecules increase, causing them to move faster and spread apart.

• Industrial Temperature Measuring Instruments:

  • Liquid-in-Glass Thermometers: Utilize thermal volumetric expansion and contraction of an internal fluid inside a calibrated glass capillary stem with a graduated scale. Typically filled with red-dyed alcohol or metallic mercury. Industrial models are encased in metal protective housings with threaded thermowell connections.

• Dial Thermometers: Use a circular graduated scale and pointer driven by internal mechanical deflection. Can be directly mounted to pipe ducts via a rigid stem or remotely linked using a fluid-filled temperature-sensing bulb connected by a flexible capillary tube.

• Bourdon Tube Dial Gauges: Composed of a curved, hollow, thin-walled oval metal tube sealed at one end. As internal fluid or refrigerant pressure rises, the curved tube straightens. This motion is transmitted through mechanical linkages and gears to drive an indicating pointer over a calibrated pressure scale.

• Thermocouples: Thermoelectric temperature sensors consisting of two dissimilar metal wires welded together at a measuring junction. When heated, the temperature difference between the measuring junction and reference junctions produces an electrical voltage (Seebeck effect) proportional to temperature, which is registered by an attached instrument.

• Bimetal Thermometers and Thermostats: Constructing an element by bonding two metals with different coefficients of thermal expansion (e.g., high-expansion copper laminated to low-expansion Invar). When exposed to heat, unequal expansion causes the bimetal strip or coil to bend.

  • Open Contact: Uses a bimetallic coil with a movable contact that meets a stationary contact, aided by a permanent magnet for snap action.

  • Mercury Bulb Thermostat: The bimetal coil tilts a sealed glass bulb containing liquid mercury to bridge open electrical leads.

• Electric Resistance / Thermistor Thermometers: Operate on the principle that the electrical resistance of conductive or semiconductor materials varies predictably with temperature.

  • Wire-Wound RTDs (Resistance Temperature Detectors): Pure platinum wire wound around a ceramic insulating core within a protective metal sheath sealed with end sealant.

  • Thin-Film RTDs: A thin film of platinum deposited onto a ceramic substrate.

  • Thermistors: Solid-state temperature sensors formed from sintered metal oxides or ceramic/polymer discs. They display large changes in electrical resistance over narrow temperature intervals.

  • Electric Resistance Pyrometer: An electrical circuit consisting of a wire coil, a low-voltage power supply, and a calibrated millivoltmeter.

• Infrared Thermometers: Non-contact optical instruments that focus and detect infrared radiation emitted by objects above absolute zero ($-460^\circ\text{F}$ / $-273^\circ\text{F}$). They convert thermal radiation into electrical signals displayed digitally. Features include adjustable emissivity ($\epsilon = 0.88$), laser sighting, high/low threshold alarms ($\text{HAL}$, $\text{LAL}$), and data logging buttons.

Temperature Scales and Conversion Mathematics

• Common Global Temperature Scales:

• Geographic Distribution of Standard Scales:

  • Fahrenheit ($^\circ\text{F}$): Used in the United States and its territories, the Cayman Islands, and Liberia.

  • Celsius ($^\circ\text{C}$): Used across the rest of the world as the international metric standard.

• Mathematical Temperature Conversion Formulas:

  • Between water freezing and boiling, the Fahrenheit scale spans $180^\circ$ ($212 - 32$), while the Celsius scale spans $100^\circ$ ($100 - 0$), yielding a ratio of $180/100 = 9/5$ (or $5/9$ in reverse):

  • Fahrenheit to Celsius Conversion:     $^\circ\text{C} = (^\circ\text{F} - 32) \times \frac{5}{9}$

  • Example: Convert $212^\circ\text{F}$ to Celsius:       $^\circ\text{C} = (212 - 32) \times \frac{5}{9} = 180 \times \frac{5}{9} = 100^\circ\text{C}$

  • Celsius to Fahrenheit Conversion:     $^\circ\text{F} = \left(^\circ\text{C} \times \frac{9}{5}\right) + 32$

  • Example: Convert $100^\circ\text{C}$ to Fahrenheit:       $^\circ\text{F} = \left(100 \times \frac{9}{5}\right) + 32 = 180 + 32 = 212^\circ\text{F}$

Heat Capacity and Thermal Energy Units

• The British Thermal Unit ($\text{Btu}$):

  • The amount of heat energy required to raise the temperature of $1\,\text{lb}$ of pure liquid water by $1^\circ\text{F}$ at standard atmospheric pressure ($1\,\text{atm}$), measured at water's maximum density temperature of $39.1^\circ\text{F}$.

• Specific Heat Capacity ($c$):

  • The ratio of the quantity of heat required to raise the temperature of a unit mass of a given substance by one degree relative to the heat required to raise the temperature of an identical mass of pure water by one degree.

  • The specific heat of pure liquid water is standardized as $1.000\,\text{Btu/lb}\cdot^\circ\text{F}$ ($4.19\,\text{kJ/kg}\cdot^\circ\text{C}$.

  • Thermal Energy Conversion Equivalent:     $1\,\text{kJ/kg}\cdot^\circ\text{C} = 0.2389\,\text{kcal/kg}\cdot^\circ\text{C} = 0.2389\,\text{Btu/lb}\cdot^\circ\text{F}$

• Specific Heat of Common Materials: