FTCE Middle Grades Science 5-9 (004) flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Hypothesis

A testable, falsifiable proposed explanation for an observation, stated so that an experiment can support or refute it using measurable evidence.

Independent variable

The factor the researcher deliberately changes or manipulates between trials, so its effect on the measured outcome can be evaluated.

Dependent variable

The factor that is measured or observed in response to the independent variable; its value is the data recorded during the experiment.

Control group

A comparison group that does not receive the experimental treatment, or receives a placebo, establishing a baseline against which results are judged.

Accuracy versus precision

Accuracy is how close a measurement is to the true value; precision is how close repeated measurements are to one another.

Scientific theory

A well-substantiated explanation of natural phenomena supported by extensive, repeated evidence and accepted by the scientific community, not a mere guess.

Percent error

A measure of deviation calculated as the absolute difference between measured and accepted values, divided by the accepted value, times 100.

Newton's second law

The net force on an object equals its mass times its acceleration (F = ma), so greater force or smaller mass produces greater acceleration.

Kinetic energy

The energy of motion, calculated as one-half mass times velocity squared; doubling velocity quadruples kinetic energy.

Density

Mass per unit volume of a substance; an object floats in a fluid when its density is lower than the fluid's density.

Buoyant force

An upward force on an object in a fluid equal to the weight of the fluid the object displaces, as described by Archimedes' principle.

Conduction

Heat transfer through direct contact, in which faster-moving particles pass energy to slower neighbors without bulk movement of the material.

Convection

Heat transfer by circulation of a fluid, where warmer, less dense material rises and cooler, denser material sinks, forming currents.

Radiation

Heat transfer by electromagnetic waves, which requires no physical medium and can travel through the vacuum of space from the Sun.

Valence electrons

Electrons in the outermost energy level of an atom; they determine bonding behavior and chemical properties of the element.

Law of conservation of mass

In a closed system, matter is neither created nor destroyed in a chemical reaction, so total mass of reactants equals total mass of products.

pH scale

A logarithmic scale from 0 to 14 measuring hydrogen ion concentration; below 7 is acidic, 7 is neutral, and above 7 is basic.

Cell theory

The principle that all living organisms are composed of cells, cells are the basic unit of life, and new cells arise from existing cells.

Mitosis

Cell division producing two genetically identical diploid daughter cells, used for growth, repair, and asexual reproduction in many organisms.

Meiosis

Cell division producing four genetically varied haploid gametes, involving crossing over and independent assortment to increase genetic diversity.

Base pairing rule

In DNA, adenine pairs with thymine and guanine pairs with cytosine; in RNA, adenine pairs with uracil instead of thymine.

Photosynthesis

The process in chloroplasts where plants use light energy to convert carbon dioxide and water into glucose and oxygen.

Cellular respiration

The process in mitochondria that breaks down glucose to release stored energy as ATP, consuming oxygen and producing carbon dioxide and water.

Natural selection

The mechanism of evolution in which heritable traits that improve survival and reproduction become more common in a population over generations.

Homeostasis

The maintenance of stable internal conditions in an organism through feedback mechanisms, such as regulating body temperature and blood glucose.

Carrying capacity

The maximum population size of a species that a given environment can sustain indefinitely with available resources and space.

Plate tectonics

The theory that Earth's lithosphere is divided into moving plates whose interactions at boundaries cause earthquakes, volcanoes, and mountain building.

Rock cycle

The continuous process by which igneous, sedimentary, and metamorphic rocks form and transform through melting, cooling, weathering, erosion, and heat and pressure.

Erosion

The transport of weathered rock and soil particles from one location to another by agents such as water, wind, ice, or gravity.

Seasons

Annual variations in sunlight angle and day length caused by Earth's 23.5-degree axial tilt as it revolves around the Sun.

Spring tide

An unusually high and low tide occurring at new and full moons, when the Sun, Earth, and Moon align and their gravitational effects combine.

Law of superposition

A relative dating principle stating that in undisturbed sedimentary rock layers, older layers lie below younger layers unless later forces overturn them.