B. Key Science Concepts
......Key Science Concepts Menu
The scientifically literate person understands and accurately applies appropriate science concepts, principles, laws, and theories in interacting with society and the environment.
Among the key concepts of science are:
B1 change D(K-12)
It is the process of becoming different. It may involve several stages.
Examples:
An organism develops from an egg, matures, and eventually dies.
Stars use up their fuel and thus undergo change.
B2 interaction D(K-12)
This happens when two or more things influence or affect each other.
Example:
Within an ecosystem some animals have to compete for available food and space.
B3 orderliness D(K-12)
This is a regular sequence which either exists in nature or is imposed through classification.
Examples:
Crystal structures can be identified by diffraction techniques because of the regular arrangement of their atoms.
B4 organism D(K-12)
An organism is a living thing or something that was once alive.
Examples:
Whether or not a virus is a living organism is an interesting topic for scientific scrutiny.
Fossils found in sedimentary rock provide evidence of organisms which became extinct a long time ago.
B5 perception D(K-12)
Perception is the interpretation of sensory input by the brain.
Example:
Jet lag may impair the judgement of pilots during landing and takeoff.
B6 symmetry D(K-12)
This is a repetition of a pattern within some larger structure.
Example:
Some molecular structures and living organisms exhibit properties of symmetry.
B7 force P(K-1), D(2-12)
It is a push or a pull.
Example:
The weight of an object decreases at higher altitudes.
B8 quantification P(K-1), D(2-12)
Numbers can be used to convey important information.
Example:
The gravitational force of attraction between two objects can be calculated by using Newton's Law of Universal Gravitation.
B9 reproducibility of results P(K-2), D(3-12)
Repetition of a procedure should produce the same results if all other conditions are identical. It is a necessary characteristic of scientific experiments.
Example:
Heating a pure sample of paradichlorobenzene should cause it to melt at about 50 °C
B10 cause-effect P(K-2), D(3-12)
It is a relationship of events that substantiates the belief that natural phenomena do not occur randomly. It enables predictions to be made. The advent of chaos theory has caused some rethinking of this principle.
Examples:
The acceleration of a cart depends on the unbalanced force acting upon the cart.
Every event has a cause. It does not happen by itself.
B11 predictability P(K-3), D(4-12)
Patterns can be identified in nature. From those patterns inferences can be made.
Example:
When sodium metal reacts with water, the resulting solution turns red litmus paper blue.
B12 conservation P(K-4), D(5-12)
An understanding of the finite nature of the world's resources, and an understanding of the necessity to treat those resources with prudence and economy, are underlying principles of conservation.
Examples:
Insulating a home may reduce the amount of energy needed to heat it in the winter.
Smaller, more efficient internal combustion engines can be designed to use less fuel.
B13 energy-matter P(1-2), D(3-12)
It is the interchangeable and dependent relationship between energy and matter.
Example:
When a candle burns, some of the energy stored in the wax is released as heat and light.
B14 cycle P(1-2), D(3-12)
Certain events or conditions are repeated.
Examples:
The water cycle, nitrogen cycle, and equilibrium all serve as examples of cycles.
Change occurring in cycles or patterns is one of the twelve principles of Indian philosophy.
B15 model P(1-2), D(3-12)
It is a representation of a real structure, event, or class of events intended to facilitate a better understanding of abstract concepts or to allow scaling to a manageable size.
Example:
Watson and Crick developed a model of the DNA molecule which allowed people to gain a better understanding of genetics.
B16 system P(1-2), D(3-12)
A set of interrelated parts forms a system.
Example:
Chemical equilibrium can be established only in a closed system.
B17 field P(1-2), D(3-12)
A field is a region of space which is influenced by some agent.
Examples:
Similarly charged objects have a tendency to repel one another when they are in close proximity.
The sun is the source of a gravitational field which fills space. The Earth's motion is affected by the influence of this field.
B18 population P(3), D(4-12)
A population is a group of organisms that share common characteristics.
Example:
Wildlife biologists monitor white tail deer to determine the number of permits for hunting that will be issued in a particular zone.
B19 probability P(3-8), D(9-12)
Probability is the relative degree of certainty that can be assigned to certain events happening in a specified time interval or within a sequence of events.
Example:
The probability of getting some types of cancer increases with prolonged exposure to large doses of radiation.
B20 theory P(3-9), D(10-12)
A theory is a connected and internally consistent group of statements, equations, models, or a combination of these, which serves to explain a relatively large and diverse group of things and events.
Example:
As new experimental evidence becomes available, atomic theory undergoes further change and refinement.
B21 accuracy P(5-8), D(9-12)
Accuracy involves a recognition that there is uncertainty in measurement. It also involves the correct use of significant figures.
Example:
A stopwatch which measures to the nearest 1/10th of a second would be an inappropriate instrument for determining the duration of a spark discharge.
B22 fundamental entities P(6), D(7-12)
They are units of structure or function which are useful in explaining certain phenomena.
Examples:
The cell is the basic unit of organic structure.
The atom is the basic unit of molecular structure.
B23 invariance P(6), D(7-12)
This is a characteristic which stays constant even though other things may change.
Example:
Mass is conserved in a chemical reaction.
B24 scale P(6), D(7-12)
Scale involves a change in dimensions. This may affect other characteristics of a system.
Example:
A paper airplane made from a sheet of notebook paper may fly differently than a plane of identical design made from a poster-sized sheet of the same paper.
B25 time-space P(6-7), D(8-12)
It is a mathematical framework in which it is convenient to describe objects and events.
Examples:
An average human being has an extension in one direction of approximately 1 3/4 metres and in another direction of about 70 years.
According to general relativity, gravity is not a force, but a property of space itself. It is a curvature in time-space caused by the presence of an object.
B26 evolution P(6-8), D(9-12)
Evolution is a series of changes that can be used to explain how something got to be the way it is or what it might become in the future. It is generally regarded as going from simple to complex.
Example:
Organic evolution is thought to progress in small, incremental changes. Similarly, scientific theories undergo change to accommodate new data as they become available.
B27 amplification P(8), D(9-12)
Amplification is an increase in magnitude of some detectable phenomenon.
Example:
A loudspeaker produces an amplification of sound.
B28 equilibrium P(9), D(10-12)
Equilibrium is the state in which there is no change on the macroscopic level and no net forces on the system.
Examples:
Chemical equilibrium exhibits no change on the macroscopic level.
A first class lever in a condition of static equilibrium remains at rest. The sum of all of the moments of the forces acting is zero.
B29 gradient P(9), D(10-12)
A gradient is a description of a pattern or variation. The description includes both the magnitude and the direction of the change.
Examples:
Light intensity decreases in a predictable manner as the distance from the light source increases.
On a mountain, the direction in which the change of slope is smallest is the most desirable route to build a railroad line.
B30 resonance P(9), D(10-12)
It is an action within one system which causes a similar action within another system.
Examples:
A hollow wooden box can be used to amplify the sound of a tuning fork.
B31 significance P(9), D(10-12)
It is the belief that certain differences exceed those that would be expected to be caused by chance alone.
Example:
An analysis of Brahe's data led to the development of Kepler's First Law.
B32 validation P(9), D(10-12)
Validation is a belief that similar relationships obtained by two or more different methods reflect an accurate representation of the situation being investigated.
Example:
Carbon-14 dating can be used to check the authenticity of archaeological artifacts.
B33 entropy P(9-10), D(11-12)
Entropy is the randomness, or disorder, in a collection of things. It can never decrease in a closed system.
Example:
When solid sodium chloride dissolves in water, its particles are dispersed randomly.