Chapter 2: Science, Matter Energy and Systems

Question 1

Data Collection

Answer 1

Scientists gather information to answer specific questions

Question 2

Hypothesis Formation

Answer 2

Based on the date, they propose a scientific hypothesis

Question 3

Model Development

Answer 3

They might create a physical or mathematical simulation of a system

Question 4

Theory Formation

Answer 4

A scientific theory is a well-tested and accepted hypothesis or set of hypotheses

Question 5

3 Characteristics of Scientists

Answer 5

1. Curiosity: Scientists have a natural desire to learn and understand
2. Skepticism: They question everything and don’t accept facts without evidence
3. Peer review: An essential feedback mechanism where other experts evaluate a scientist’s work

Question 6

3 Guidelines for Scientific Thinking

Answer 6

1. Critically analyse all information
2. Use multiple reliable sources to evaluate evidence and hypotheses
3. Recognize personal biases and differentiate between facts and opinions

Question 7

Scientific Law

Answer 7

A consistent and universal description of observed phenomena in nature

Question 8

Tentative Science

Answer 8

Early scientific results that haven’t undergone extensive testing or peer review

Question 9

4 Limitations of Science

Answer 9

1. Uncertainty: Absolute certainty is unattainable in science
2. Human Bias: Scientists, being human, might have biases. Peer reviews help mitigate this
3. Complex Systems: Many natural systems are complex with numerous variables. Mathematical models assist in understanding these
4. Statistical Tools: They are used to interpret data and understand patterns

Question 10

Matter

Answer 10

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

Question 11

Element

Answer 11

A substance that cannot be broken down into simpler substances by chemical means. Examples include gold and mercury

Question 12

Compound

Answer 12

A substance formed by the combination of two or more elements in fixed proportions. For instance, water (H20) is a compound

Question 13

Atom

Answer 13

The smallest unit of an element that retains its chemical properties. It’s the foundational building block of matter

Question 14

Each atom consists of three types of subatomic particles

Answer 14

1. Neutrons: Neutral charge
2. Protons: Positive charge
3. Electrons: Negative charge

Question 15

Nucleus

Answer 15

The central part of an atom containing protons and neutrons

Question 16

Atomic Number

Answer 16

Represents the number of protons in an atom’s nucleus

Question 17

Mass Number

Answer 17

The combined total of protons and neutrons in an atom’s nucleus

Question 18

Isotopes

Answer 18

Variants of an element with the same atomic number but different mass numbers

Question 19

Molecule

Answer 19

A combination of two or more atoms bonded together

Question 20

Ion

Answer 20

An atom or group of atoms that has gained or lost electrons, resulting in a net positive or negative charge

Question 21

pH Measure

Answer 21

Used to determine the acidity or basicity of a solution based on the concentration of H+ and OH- ions

Question 22

Organic Compounds

Answer 22

Molecules containing carbon atoms, excluding simple carbon compounds like CO2

Question 23

Macromolecules

Answer 23

Large organic molecules, including carbohydrates, proteins, nucleic acids, and lipids

Question 24

Cell Theory

Answer 24

All living organisms are composed of cells

Question 25

DNA

Answer 25

A molecule that carries genetic information. It's composed of sequences of nucleotides called genes

Question 26

Physical Change

Answer 26

A transformation in which the chemical composition of matter remains unchanged

Question 27

Chemical Change

Answer 27

A transformation in which the chemical composition of matter is altered

Question 28

Law of Conservation of Matter

Answer 28

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

Question 29

Energy

Answer 29

The ability to do work. Can be measured in units like joules, kilojoules, calories and kilocalories

Question 30

Work

Answer 30

In scientific terms, work is the force applied to an object over a distance (work = force*distance)

Question 31

Kinetic Energy

Answer 31

Energy associated with motion. Examples include flowing water, electric power and heat

Question 32

Heat

Answer 32

Thermal energy that can be transferred through radiation, conduction and convection

Question 33

Radiation

Answer 33

Transfer of heat energy through space via electromagnetic radiation, primarily infrared radiation

Question 34

Conduction

Answer 34

Transfer of heat between two solid substances in direct contact

Question 35

Convection

Answer 35

Transfer of heat in a fluid (liquid or gas) through the movement of the fluid itself

Question 36

Potential Energy

Answer 36

Energy that is stored and potentially available for use, can be converted into kinetic energy

Question 37

Renewable Energy

Answer 37

Derived from resources that are naturally replenished in a short time, e.g., solar, wind, and hydro energy

Question 38

Non-Renewable Energy

Answer 38

Derived from resources that can be depleted and aren't replenished quickly, e.g., fossil fuels like oil, coal, and natural gas

Question 39

Commercial Energy

Answer 39

Energy sold in the marketplace, with 90% coming from non-renewable sources, primarily fossil fuels

Question 40

Energy Quality

Answer 40

The capacity of energy to perform useful work. High-quality energy includes high-temperature heat, concentrated sunlight, and high-speed wind

Question 41

First Law of Thermodynamics (Law of Conservation of Energy)

Answer 41

Energy cannot be created or destroyed, only transformed. In any energy conversion, the total amount of energy remains constant

Question 42

Second Law of Thermodynamics

Answer 42

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

Question 43

Energy Efficiency

Answer 43

A measure of how much useful work is achieved for each unit of energy input. Improving energy efficiency can reduce pollution and costs

Question 44

System

Answer 44

A set of components that interact and function together in a regular way

Question 45

3 Key Components of Systems

Answer 45

1. Inputs: These are the matter, energy and information that a system receive from its environment 2. Throughputs (or Flows): These are the processes within the system that transform the inputs using matter, energy, and information 3. Outputs: These are the matter, energy, and information that a system releases into its environment after processing

Question 46

Feedback

Answer 46

Feedback mechanisms are processes that can influence the behavior of a system. They can either amplify (positive) or dampen (negative) changes within the system

Question 47

Positive Feedback Loop

Answer 47

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

Question 48

Negative Feedback Loop

Answer 48

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

Question 49

Ecological Tipping Point

Answer 49

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

Question 50

System Stability and Change

Answer 50

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