Chapter 2: Science, Matter Energy and Systems Flashcards
Data Collection
Scientists gather information to answer specific questions
Hypothesis Formation
Based on the date, they propose a scientific hypothesis
Model Development
They might create a physical or mathematical simulation of a system
Theory Formation
A scientific theory is a well-tested and accepted hypothesis or set of hypotheses
3 Characteristics of Scientists
- Curiosity: Scientists have a natural desire to learn and understand
- Skepticism: They question everything and don’t accept facts without evidence
- Peer review: An essential feedback mechanism where other experts evaluate a scientist’s work
3 Guidelines for Scientific Thinking
- Critically analyse all information
- Use multiple reliable sources to evaluate evidence and hypotheses
- Recognize personal biases and differentiate between facts and opinions
Scientific Law
A consistent and universal description of observed phenomena in nature
Tentative Science
Early scientific results that haven’t undergone extensive testing or peer review
4 Limitations of Science
- Uncertainty: Absolute certainty is unattainable in science
- Human Bias: Scientists, being human, might have biases. Peer reviews help mitigate this
- Complex Systems: Many natural systems are complex with numerous variables. Mathematical models assist in understanding these
- Statistical Tools: They are used to interpret data and understand patterns
Matter
Anything that occupies space and has mass. It can exist in solid, liquid, or gas states and can be classified into elements and compounds based on its chemical composition
Element
A substance that cannot be broken down into simpler substances by chemical means. Examples include gold and mercury
Compound
A substance formed by the combination of two or more elements in fixed proportions. For instance, water (H20) is a compound
Atom
The smallest unit of an element that retains its chemical properties. It’s the foundational building block of matter
Each atom consists of three types of subatomic particles
- Neutrons: Neutral charge
- Protons: Positive charge
- Electrons: Negative charge
Nucleus
The central part of an atom containing protons and neutrons
Atomic Number
Represents the number of protons in an atom’s nucleus
Mass Number
The combined total of protons and neutrons in an atom’s nucleus
Isotopes
Variants of an element with the same atomic number but different mass numbers
Molecule
A combination of two or more atoms bonded together
Ion
An atom or group of atoms that has gained or lost electrons, resulting in a net positive or negative charge
pH Measure
Used to determine the acidity or basicity of a solution based on the concentration of H+ and OH- ions
Organic Compounds
Molecules containing carbon atoms, excluding simple carbon compounds like CO2
Macromolecules
Large organic molecules, including carbohydrates, proteins, nucleic acids, and lipids
Cell Theory
All living organisms are composed of cells
DNA
A molecule that carries genetic information. It’s composed of sequences of nucleotides called genes
Physical Change
A transformation in which the chemical composition of matter remains unchanged
Chemical Change
A transformation in which the chemical composition of matter is altered
Law of Conservation of Matter
States that matter cannot be created or destroyed, only transformed. This means that the number of atoms remains constant before and after any physical/chemical change
Energy
The ability to do work. Can be measured in units like joules, kilojoules, calories and kilocalories
Work
In scientific terms, work is the force applied to an object over a distance (work = force*distance)
Kinetic Energy
Energy associated with motion. Examples include flowing water, electric power and heat
Heat
Thermal energy that can be transferred through radiation, conduction and convection
Radiation
Transfer of heat energy through space via electromagnetic radiation, primarily infrared radiation
Conduction
Transfer of heat between two solid substances in direct contact
Convection
Transfer of heat in a fluid (liquid or gas) through the movement of the fluid itself
Potential Energy
Energy that is stored and potentially available for use, can be converted into kinetic energy
Renewable Energy
Derived from resources that are naturally replenished in a short time, e.g., solar, wind, and hydro energy
Non-Renewable Energy
Derived from resources that can be depleted and aren’t replenished quickly, e.g., fossil fuels like oil, coal, and natural gas
Commercial Energy
Energy sold in the marketplace, with 90% coming from non-renewable sources, primarily fossil fuels
Energy Quality
The capacity of energy to perform useful work. High-quality energy includes high-temperature heat, concentrated sunlight, and high-speed wind
First Law of Thermodynamics (Law of Conservation of Energy)
Energy cannot be created or destroyed, only transformed. In any energy conversion, the total amount of energy remains constant
Second Law of Thermodynamics
In any energy transformation, the quality of energy decreases, meaning it becomes less useful. This is often referred to as the increase in entropy or disorder
Energy Efficiency
A measure of how much useful work is achieved for each unit of energy input. Improving energy efficiency can reduce pollution and costs
System
A set of components that interact and function together in a regular way
3 Key Components of Systems
- Inputs: These are the matter, energy and information that a system receive from its environment
- Throughputs (or Flows): These are the processes within the system that transform the inputs using matter, energy, and information
- Outputs: These are the matter, energy, and information that a system releases into its environment after processing
Feedback
Feedback mechanisms are processes that can influence the behavior of a system. They can either amplify (positive) or dampen (negative) changes within the system
Positive Feedback Loop
This type of feedback amplifies changes in a system. E.g. the more the population grows, the more individuals can reproduce, leading to a high growth
Negative Feedback Loop
This type of feedback counteracts changes in a system, bringing it back to a state of equilibrium. E.g. A thermostat: when the room temperature rises above a set point, the heating system turns off, and when it is below a set point it turns on
Ecological Tipping Point
This is a point beyond which a system can undergo drastic changes, leading to severe degradation or even collapse. It’s the point where the system can’t return to its original state due to the changes being too significant. E.g. if a lake is too polluted, all fish might die, ecosystem could collapse
System Stability and Change
Systems can be stable, showing little change over time, or they can fluctuate. The stability of a system can be influenced by external factors and internal feedback loops. When systems are pushed too far from their stable state, they can undergo rapid and sometimes irreversible changes
