Chapter 2 Vocabulary Flashcards
Data
Information needed to answer scientists questions.
Scientific Hypothesis
A possible explanation of what scientists observe in nature or in the results of their experiments.
Model
An approximate representation or simulation of a system.
Scientific theory
A well-tested and widely accepted scientific hypothesis or a group of related hypotheses.
Peer review
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.
Scientific law (law of nature)
A well-tested and widely accepted description of what we find happening repeatedly in nature in the same way.
Tentative science (frontier science)
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.
Reliable Science
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.
Unreliable Science
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.
Matter
Is anything that has mass and takes up space. It
can exist in three physical states—solid, liquid, and gas.
Element
Is a fundamental type of matter that has a unique set of properties and cannot be broken down into simpler substances by chemical means.
Compounds
Combinations of two or more different
elements held together in fixed proportions.
Atom
The smallest unit of matter into which an element can be divided and still have its characteristic chemical properties.
Atomic theory
The idea that all elements are made up of atoms and is the most widely accepted scientific theory in chemistry.
Neutrons (n)
Subatomic particle with no electrical charge.
Protons (p)
Subatomic particles with a positive electrical charge (+).
Electrons (e)
Subatomic particles with a negative electrical charge (-).
Nucleus
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.
Atomic number
Is equal to the number of protons in the nucleus of its atom.
Mass number
The total number of neutrons and protons in an atom’s nucleus.
Isotopes
The forms of an element having the same
atomic number but different mass numbers.
Molecule
A combination of two or more atoms of the same or different elements held together by forces called chemical bonds.
Ion
An atom or a group of atoms with one or more net
positive or negative electrical charges.
Acidity
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.
pH
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.
Chemical formula
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.
Organic compounds
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.
Inorganic compounds
All other compounds that are not organic compounds. One exception, methane (CH4), has only one carbon atom but is considered an organic
compound.
Cells
The fundamental structural and functional units of life.
Genes
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.
Trait
Each of these genes leads to a specific trait, or characteristic, passed on from parents to offspring during reproduction in an animal or plant.
Chromosome
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.
Matter quality
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.
High-quality matter
Is highly concentrated, is typically found near the earth’s surface, and has great potential for use as a resource.
Low-quality matter
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.
Physical change
When a sample of matter undergoes this change, there is no change in its chemical composition.
Chemical change (chemical reaction)
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.
Nuclear change
Change in the nuclei of its (matter) atoms: radioactive decay, nuclear fission, and nuclear fusion
Law of conservation of matter
Whenever matter undergoes a physical or chemical change, no atoms are created or destroyed.
Energy
The capacity to do work or to transfer heat.
Heat
(Another form of kinetic energy) The total
kinetic energy of all moving atoms, ions, or molecules within a given substance.
Electromagnetic radiation
In which energy travels in the form of a wave as a result of changes in electrical and magnetic fields.
Kinetic energy
Which is energy associated with motion. (Matter in motion has this)
Potential energy
Energy which is stored and potentially available for use.
Energy quality
Is a measure of the capacity of a type of energy to do useful work.
High-quality energy
Has a great capacity to do useful work because it is concentrated.
Low-quality energy
Is so dispersed that it has little capacity to do useful work.
First law of thermodynamics (the law of conservation of energy)
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.
Fossil fuels
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.
Second law of thermodynamics
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.
System
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.
Input
Matter, energy, or information entering a system (from the environment).
Flows or Throughput
Rate of flow of matter, energy, or information through a system.
Output
Matter, energy, or information leaving a system.
Science
Is a human effort to discover how the physical world works by making observations and measurements, and carrying out experiments.
Feedback
any process that increases (positive feedback) or decreases (negative feedback) a change
to a system
Feedback loop
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.
Positive feedback loop
Causes a system to change further in the same direction.
Negative or corrective feedback loop
Causes a system to change in the opposite direction from which is it moving.
Tipping point (threshold level)
The point at which a fundamental shift in the
behavior of a system occurs.
Synergistic interaction or synergy
Occurs when two or more processes interact so that the combined effect is greater than the sum of their separate effects.
