NB Grade 8 Scientific Literacy flashcards
NB Grade 8 Scientific Literacy · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Independent variable
- The factor that the experimenter deliberately changes or manipulates in an investigation, so its effect on the measured outcome can be observed and compared.
- Dependent variable
- The factor that is measured or observed in an experiment; it responds to changes in the independent variable and provides the data used to judge the hypothesis.
- Control group
- The group in an experiment that receives no treatment or a placebo, providing a baseline for comparison with the experimental group.
- Hypothesis
- A testable, falsifiable prediction about the relationship between variables, stated so that collected evidence could support or contradict it.
- Reliability
- The consistency of repeated measurements or trials; a reliable procedure yields similar results when repeated under the same conditions.
- Observation vs. inference
- An observation is a direct reading from the senses or an instrument; an inference is a conclusion or explanation drawn from those observations.
- Cell theory
- The principle that all living things are made of cells, cells are the basic unit of structure and function, and new cells arise from existing cells.
- Mitochondria
- Organelles in eukaryotic cells that release usable energy from food through cellular respiration; often called the powerhouse of the cell.
- Chloroplast
- The plant-cell organelle containing chlorophyll that captures light energy and carries out photosynthesis, producing glucose and releasing oxygen.
- Prokaryote vs. eukaryote
- Prokaryotes lack a membrane-bound nucleus and organelles; eukaryotes have a nucleus and membrane-bound organelles such as mitochondria.
- Mitosis vs. meiosis
- Mitosis produces two identical body cells for growth and repair; meiosis produces four genetically varied gametes with half the chromosome number.
- Levels of organization
- The hierarchy of living structures: cells form tissues, tissues form organs, organs form organ systems, and organ systems form an organism.
- Homogeneous mixture
- A mixture with uniform composition throughout, such as salt water, in which the individual components are not visibly distinguishable.
- Density formula
- Density equals mass divided by volume (D = m/V); objects denser than their surrounding fluid sink, and less dense objects float.
- Filtration
- A separation technique that uses a porous barrier to trap solid particles while allowing a liquid or gas to pass through.
- Physical change
- A change in a substance's size, shape, or state that does not alter its chemical identity, such as melting or dissolving.
- Chemical change
- A change that produces a new substance with different properties, often signaled by color change, gas, precipitate, or energy release.
- Conservation of mass
- The principle that in a closed system the total mass before a change equals the total mass after it; matter is neither created nor destroyed.
- Newton's first law
- An object at rest or moving at constant velocity stays that way unless a net external force acts on it; this property is inertia.
- Newton's second law
- The net force on an object equals its mass times its acceleration (F = ma); greater mass under the same force accelerates less.
- Newton's third law
- For every action force there is an equal and opposite reaction force acting on a different object; forces always occur in pairs.
- Speed formula
- Speed equals distance divided by time; velocity is speed in a stated direction, and acceleration is the rate of change of velocity.
- Kinetic energy
- The energy of motion, calculated as one-half mass times velocity squared (KE = 1/2 mv^2); doubling speed quadruples kinetic energy.
- Balanced vs. unbalanced forces
- Balanced forces cancel to zero net force and do not change motion; unbalanced forces produce acceleration in the direction of the net force.
- Earth's layers
- Earth consists of a rocky crust, a hot slowly flowing mantle, a liquid outer core, and a solid inner core made mostly of iron and nickel.
- Igneous rock
- Rock formed when molten magma or lava cools and solidifies; slow cooling underground produces large crystals, rapid cooling produces fine crystals.
- Sedimentary rock
- Rock formed when weathered sediments are deposited, compacted, and cemented together over time; it often contains fossils and layers.
- Metamorphic rock
- Rock that has been changed by intense heat and pressure while remaining solid, often producing new mineral alignment or banding.
- Rock cycle
- The continuous set of processes, including melting, cooling, weathering, erosion, deposition, and metamorphism, that transforms rock among the three types.
- Seasons cause
- Seasons result from Earth's tilted axis as it revolves around the Sun, changing the angle and duration of sunlight at each latitude.
- Renewable resource
- A natural resource, such as solar, wind, or hydro energy, that is replenished by natural processes on a human timescale.
- Engineering design cycle
- A repeating process of defining a problem, researching, designing, building and testing a prototype, then evaluating results and redesigning to improve.