Science & the Environment (SCIE 1002) - Lecture 1: Matter, Earth and Energy
The Nature of Science
Science is a process to solve problems or develop understanding of nature by testing possible answers.
The scientific method is a way of gaining information by forming and rigorously testing hypotheses.
Basic Sciences
Biology: Scientific study of life.
Chemistry: Study of properties, composition, structure, transformations, and energy of elements/compounds.
Physics: Science of matter, motion, and energy, dealing with the structure and interactions of the observable universe.
Geology: Science of the solid Earth, including its rocks, minerals, structures, processes, and history.
Technology: Scientific knowledge used in practical ways in industry.
Basic Assumptions in Science
Specific causes exist for observed events and can be identified.
General rules or patterns describe observations.
Repeated events probably have the same cause.
Perceptions are not individualistic and fundamental rules of nature are universal.
Cause-and-Effect Relationships
Correlation $ \neq $ Causation.
Elements of the Scientific Method
Requires systematic information search and continuous idea reevaluation, criticism, and modification.
Steps: Observation, asking questions, forming a hypothesis, testing the hypothesis, drawing conclusions, modifying/revising hypothesis, communicating with other scientists, developing new theories/laws.
Observation: Curiosity about nature, using senses and technology.
Hypothesis: Testable and falsifiable idea/explanation, developed through inductive reasoning (specific to general).
Predictions and Experiments: Use deductive reasoning (general to specific). Experiments involve experimental variables (factor tested), responding variables (result/change), and controls (not exposed to variable).
Experimental Groups: Control group (no treatment) and experimental group (receives treatment).
Data Analysis: Results (data) presented via tables/graphs, evaluated with statistics, published in peer-reviewed scientific journals.
Limitations of Science
Distinguish between collected data and scientists’ opinions about data.
Scientific knowledge can be misused to support invalid opinions.
Pseudoscience
A deceptive practice that uses the appearance or language of science to mislead, lacking scientific validity.
The Structure of Matter
Matter: Anything that has mass and takes up space; composed of one or more kinds of smaller sub-units (atoms) in constant motion.
Atomic Structure
Atom: Fundamental unit of matter.
Composed of: Protons (positively charged), Neutrons (neutral), and Electrons (negatively charged).
92 types of atoms found in nature; each forms a specific element.
Human body is $ \approx 99\% $ Oxygen, Hydrogen, Nitrogen, Carbon, Calcium, Phosphorus. Other essential elements: Sulfur, Potassium, Sodium, Chlorine, Magnesium.
Isotopes: Atoms of the same element differing in the number of neutrons.
The Molecular Nature of Matter
Molecules: Atoms bonded together into stable units.
Ions: Electrically charged particles (lose electrons $=$ positive, gain electrons $=$ negative).
A Word About Water
Exists in $3$ phases: solid, liquid, gas.
Covers $ \frac{3}{4} $ of Earth’s surface, influencing weather, climate, and shaping the surface.
Most common molecule in living things.
Evaporation of water cools surroundings as it requires much energy.
Water is the universal solvent.
Acids, Bases, and pH
Acid: Compound that releases hydrogen ions ($H^+$) in a solution.
Base: Compound that accepts hydrogen ions ($H^+$) in a solution.
pH Scale: Measures hydrogen ion concentration; inverse and logarithmic.
$7 =$ neutral
$0-6 =$ acidic (fewer than )
$8-14 =$ basic (more than )
Inorganic and Organic Matter
Organic matter: Molecules containing carbon atoms usually bonded in rings or chains, containing large amounts of chemical energy.
All living things contain organic compounds.
Chemical Reactions in Living Things
Photosynthesis: Plants convert inorganic material into organic material using light.
Respiration: Uses oxygen to break down large, organic molecules into smaller inorganic ones, releasing energy.
All organisms perform some form of respiration to obtain energy.
Energy Principles
Energy: The ability to perform work.
FORMS OF ENERGY
Kinetic energy: Energy associated with motion.
Thermal energy: Kinetic energy from random movement of atoms or molecules (Heat is thermal energy in transfer).
Potential energy: Energy due to location or structure.
Chemical energy: Potential energy available for release in a chemical reaction.
Energy can be converted from one form to another.
States of Matter
The state of matter depends on the amount of kinetic energy in molecules.
Solids: Low kinetic energy, molecules vibrate in place, close together.
Liquids: Moderate energy, molecules farther apart, able to exchange places.
Gases: High kinetic energy, molecules very far apart, move rapidly.
First and Second Laws of Thermodynamics
First Law: Energy cannot be created or destroyed; it can only be changed from one form to another.
Second Law: When converting energy, some useful energy is lost.
Entropy: Energy that cannot be used to do useful work.
Environmental Implications of Energy Flow
Heat produced during energy conversion dissipates into the environment.
High-quality energy: Can perform useful work (e.g., electricity).
Low-quality energy: Cannot perform useful work (e.g., heat in the ocean).
Low-quality energy still has significance (e.g., moderates coastal climates, affects weather/ocean currents).
New technologies can convert low-quality energy (e.g., light, wind) to high-quality energy (electricity).
Pollution: A consequence of energy conversion (e.g., brake wear, power plant emissions).
Reducing energy use helps lessen waste heat and pollution, as high-quality energy is limited.