Chapter 2 Vocabulary

Question 1

Data

Answer 1

Information needed to answer scientists questions.

Question 2

Scientific Hypothesis

Answer 2

A possible explanation of what scientists observe in nature or in the results of their experiments.

Question 3

Model

Answer 3

An approximate representation or simulation of a system.

Question 4

Scientific theory

Answer 4

A well-tested and widely accepted scientific hypothesis or a group of related hypotheses.

Question 5

Peer review

Answer 5

It involves scientists openly publishing details of the methods and models they used, the results of their experiments, and the reasoning behind their hypotheses for other scientists working in the same field (their peers) to evaluate.

Question 6

Scientific law (law of nature)

Answer 6

A well-tested and widely accepted description of what we find happening repeatedly in nature in the same way.

Question 7

Tentative science (frontier science)

Answer 7

Preliminary scientific results that capture news headlines that are controversial because they have not been widely tested and accepted by peer review. They are not yet considered reliable, and can be thought of as tentative science or frontier science. Some of these results will be validated and classified as reliable and some will be discredited and classified as unreliable.

Question 8

Reliable Science

Answer 8

Consists of data, hypotheses, models, theories, and laws that are widely accepted by all or most of the scientists who are considered experts in the field under study, in what is referred to as a scientific consensus.

Question 9

Unreliable Science

Answer 9

Scientific hypotheses and results that are presented
as reliable without having undergone the rigors of
widespread peer review, or that have been discarded as a result of peer review.

Question 10

Matter

Answer 10

Is anything that has mass and takes up space. It

can exist in three physical states—solid, liquid, and gas.

Question 11

Element

Answer 11

Is a fundamental type of matter that has a unique set of properties and cannot be broken down into simpler substances by chemical means.

Question 12

Compounds

Answer 12

Combinations of two or more different

elements held together in fixed proportions.

Question 13

Atom

Answer 13

The smallest unit of matter into which an element can be divided and still have its characteristic chemical properties.

Question 14

Atomic theory

Answer 14

The idea that all elements are made up of atoms and is the most widely accepted scientific theory in chemistry.

Question 15

Neutrons (n)

Answer 15

Subatomic particle with no electrical charge.

Question 16

Protons (p)

Answer 16

Subatomic particles with a positive electrical charge (+).

Question 17

Electrons (e)

Answer 17

Subatomic particles with a negative electrical charge (-).

Question 18

Nucleus

Answer 18

Each atom consists of an extremely small center
called this—containing one or more protons
and, in most cases, one or more neutrons—and one or more electrons in rapid motion somewhere around the nucleus.

Question 19

Atomic number

Answer 19

Is equal to the number of protons in the nucleus of its atom.

Question 20

Mass number

Answer 20

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

Question 21

Isotopes

Answer 21

The forms of an element having the same

atomic number but different mass numbers.

Question 22

Molecule

Answer 22

A combination of two or more atoms of the same or different elements held together by forces called chemical bonds.

Question 23

Ion

Answer 23

An atom or a group of atoms with one or more net

positive or negative electrical charges.

Question 24

Acidity

Answer 24

A chemical characteristic that helps determine how a substance dissolved in water will interact with and affect its environment; based on the comparative
amounts of hydrogen ions (H+) and hydroxide
ions (OH–) contained in a particular volume
of the solution.

Question 25

pH

Answer 25

Numeric value that indicates the relative
acidity or alkalinity of a substance on a scale
of 0 to 14, with the neutral point at 7. Acid
solutions have pH values lower than 7; basic
or alkaline solutions have pH values greater
than 7.

Question 26

Chemical formula

Answer 26

To show the number of each type of atom or ion in a compound. This shorthand contains the symbol for each element present and uses subscripts to show the number of atoms or ions of each element in the compound’s basic structural unit.

Question 27

Organic compounds

Answer 27

Plastics, as well as table sugar, vitamins, aspirin, penicillin, and most of the chemicals in your body are called this because they contain at least two
carbon atoms combined with atoms of one or more
other elements.

Question 28

Inorganic compounds

Answer 28

All other compounds that are not organic compounds. One exception, methane (CH4), has only one carbon atom but is considered an organic
compound.

Question 29

Cells

Answer 29

The fundamental structural and functional units of life.

Question 30

Genes

Answer 30

Within some DNA molecules are certain sequences of nucleotides called this. Each of these distinct pieces of DNA contains instructions, or codes, called genetic information, for making specific proteins.

Question 31

Trait

Answer 31

Each of these genes leads to a specific trait, or characteristic, passed on from parents to offspring during reproduction in an animal or plant.

Question 32

Chromosome

Answer 32

Thousands of genes make up a single one of this, a double helix DNA molecule wrapped around some proteins. Humans have 46 chromosomes, mosquitoes have 8, and a fish known as a carp has 104.

Question 33

Matter quality

Answer 33

Is a measure of how useful a form of
matter is to humans as a resource, based on its availability and concentration—the amount of it that is contained in a given area or volume.

Question 34

High-quality matter

Answer 34

Is highly concentrated, is typically found near the earth’s surface, and has great potential for use as a resource.

Question 35

Low-quality matter

Answer 35

Is not highly concentrated, is often located deep underground or dispersed in the ocean or atmosphere, and usually has little potential for use as a resource.

Question 36

Physical change

Answer 36

When a sample of matter undergoes this change, there is no change in its chemical composition.

Question 37

Chemical change (chemical reaction)

Answer 37

When this happens there is a change in the chemical composition of the substances involved. Chemists use a chemical equation to show how chemicals are rearranged in a chemical reaction.

Question 38

Nuclear change

Answer 38

Change in the nuclei of its (matter) atoms: radioactive decay, nuclear fission, and nuclear fusion

Question 39

Law of conservation of matter

Answer 39

Whenever matter undergoes a physical or chemical change, no atoms are created or destroyed.

Question 40

Energy

Answer 40

The capacity to do work or to transfer heat.

Question 41

Heat

Answer 41

(Another form of kinetic energy) The total

kinetic energy of all moving atoms, ions, or molecules within a given substance.

Question 42

Electromagnetic radiation

Answer 42

In which energy travels in the form of a wave as a result of changes in electrical and magnetic fields.

Question 43

Kinetic energy

Answer 43

Which is energy associated with motion. (Matter in motion has this)

Question 44

Potential energy

Answer 44

Energy which is stored and potentially available for use.

Question 45

Energy quality

Answer 45

Is a measure of the capacity of a type of energy to do useful work.

Question 46

High-quality energy

Answer 46

Has a great capacity to do useful work because it is concentrated.

Question 47

Low-quality energy

Answer 47

Is so dispersed that it has little capacity to do useful work.

Question 48

First law of thermodynamics (the law of conservation of energy)

Answer 48

According to this scientific law, whenever energy is converted from one form to another in a physical or
chemical change, no energy is created or destroyed.

Question 49

Fossil fuels

Answer 49

Fuels that were formed over millions of years as layers of the decaying remains of ancient plants and animals (fossils) were exposed to intense heat and pressure within the earth’s crust.

Question 50

Second law of thermodynamics

Answer 50

Whenever energy is converted from one form to another in a physical or chemical change, we end up with lower-quality or less useable energy than we started with.

Question 51

System

Answer 51

Is a set of components that function and interact in some regular way. The human body, a river, an economy, and the earth are all systems.

Question 52

Input

Answer 52

Matter, energy, or information entering a system (from the environment).

Question 53

Flows or Throughput

Answer 53

Rate of flow of matter, energy, or information through a system.

Question 54

Output

Answer 54

Matter, energy, or information leaving a system.

Question 55

Science

Answer 55

Is a human effort to discover how the physical world works by making observations and measurements, and carrying out experiments.

Question 56

Feedback

Answer 56

any process that increases (positive feedback) or decreases (negative feedback) a change
to a system

Question 57

Feedback loop

Answer 57

Occurs when an output of matter, energy, or

information is fed back into the system as an input and leads to changes in that system.

Question 58

Positive feedback loop

Answer 58

Causes a system to change further in the same direction.

Question 59

Negative or corrective feedback loop

Answer 59

Causes a system to change in the opposite direction from which is it moving.

Question 60

Tipping point (threshold level)

Answer 60

The point at which a fundamental shift in the

behavior of a system occurs.

Question 61

Synergistic interaction or synergy

Answer 61

Occurs when two or more processes interact so that the combined effect is greater than the sum of their separate effects.