8th grade science STAAR

Speed

The rate at which an object covers distance, calculated using the formula Speed = Distance / Time.

Acceleration

The rate of change of velocity of an object, calculated using the formula Acceleration = (Final Speed - Initial Speed) / Time.

Distance-time graph

A graph that represents the motion of an object; a steeper slope indicates a faster speed, while a curved line signifies changing speed.

Potential Energy

Stored energy based on position or configuration, including gravitational, elastic, chemical, and nuclear energy.

Kinetic Energy

The energy of a moving object, dependent on both mass and velocity.

Law of Conservation of Energy

A principle stating that energy cannot be created or destroyed, only transformed from one form to another.

Seasons

The divisions of the year caused by Earth’s tilt and orbit around the Sun, resulting in opposite seasons in the Northern and Southern Hemispheres.

Metals

Elements that are shiny (luster), good conductors of heat and electricity, malleable, ductile, and have high density.

Nonmetals

Elements that are dull, poor conductors of heat and electricity, brittle, and have low melting and boiling points.

Metalloids

Elements that have properties of both metals and nonmetals, often classified as semiconductors.

Unbalanced Forces

Forces that cause changes in motion, resulting in acceleration, changes in speed or direction, or deformation of objects.

Balanced Forces

Forces that are equal in size and opposite in direction, resulting in no motion or a constant velocity.

Convection Currents

Movements of air or water caused by warm air rising and cool air sinking, creating wind and ocean currents.

Biodiversity

The variety of life in a particular habitat or ecosystem, contributing to its sustainability.

Ecological Succession

The process by which ecosystems change and develop over time, either as primary succession (starting without soil) or secondary succession (with soil present).

Cell Theory

A foundational principle stating that all living things are made of cells, that cells are the basic unit of life, and that all cells come from preexisting cells.

Nucleus

The organelle in a cell that serves as the control center, housing the cell's DNA.

Mitochondria

Organelles known as the powerhouse of the cell, where energy production takes place.

Chloroplasts

Organelles found in plant cells that conduct photosynthesis, converting light energy into chemical energy.

Vacuole

A storage organelle within a cell that holds various substances, including nutrients and waste products.