Physical Science Review Flashcards

A comprehensive review of Grade 6-8 Physical Science topics including energy, matter, water properties, atmosphere, biology, genetics, and physics principles.

Potential Energy

Energy that is not "in use" and is stored.

Kinetic Energy

Energy that is "in use" and in motion, depending on the mass and velocity of the moving object.

Renewable Resources

Energy resources that are replenished or replaced over a SHORT period of time.

Nonrenewable Resources

Energy resources that take LONG periods of time to be replaced and will eventually run out.

Electrical energy

Energy created by moving electric charges.

Thermal energy

Total energy due to movement or vibration of particles.

Chemical energy

Energy stored in chemical compounds, such as in food.

Radiant energy

Light energy that travels in electromagnetic waves.

Mechanical energy

Energy associated with the motion or position of an object.

Nuclear energy

Energy stored in the nucleus of atoms.

Convection

The rising of warm air or water (which is less dense) and the sinking of cool air or water (which is denser).

Greenhouse effect

The process by which gases hold or "trap" heat in the atmosphere, keeping it at a temperature suitable for most organisms.

Matter

Anything that has mass and takes up space.

Elements

Smaller particles of matter made of one kind of atom that cannot be broken down into other substances by chemical or physical means.

Atoms

The smallest units of an element that have the properties of that element, composed of protons, neutrons, and electrons.

Compounds

Pure substances made up of two or more elements that are chemically combined in fixed mass ratios.

Solution

A mixture of two or more substances in which the molecules are evenly distributed.

Solute

The substance that is dissolved in a solution, typically present in the smallest amount.

Solvent

The substance in which the solute dissolves, typically present in the largest amount.

Surface tension

The tightness across the surface of water caused by polar molecules pulling on one another, making the surface act like a solid.

Cohesion

The attractive force between water molecules; water's attraction to itself.

Adhesion

The attraction of water molecules to other substances.

Capillary action

The combined force of attraction among water molecules and the molecules of the surrounding material (Cohesion + Adhesion).

Specific Heat

The amount of energy needed to increase the temperature of something $1^{\circ}\text{C}$.; water has a high specific heat due to the strong attraction between molecules.

Physical Weathering

Also known as mechanical weathering, it is the process of rocks breaking into smaller pieces without changing their chemical composition.

Chemical weathering

The breakdown of rocks through chemical changes caused by water, oxygen, carbon dioxide, organisms, and acid rain.

Atmosphere

A mixture of gases surrounding the Earth, consisting of $78\%$ Nitrogen, $21\%$ Oxygen, and $1\%$ other gases.

Troposphere

The layer of the atmosphere closest to Earth's surface where virtually all weather occurs and life exists.

Stratosphere

The layer of the atmosphere above the troposphere that contains the ozone layer which absorbs ultraviolet radiation.

Mesosphere

The layer of the atmosphere where most meteors from space burn up, with temperatures decreasing to as low as $-93^{\circ}\text{C}$.

Thermosphere

The layer containing the ionosphere and where auroras occur, with temperatures that can soar to $1,727^{\circ}\text{C}$.

Exosphere

The outermost layer of the atmosphere that merges with the vacuum of outer space.

Watershed

The land that water flows across or through on its way to a stream, lake, wetland, or other body of water.

Wetlands

Transition zones between dry land and bodies of water that act like sponges to regulate water flow and maintain water quality.

Estuaries

Bodies of water found where rivers meet the sea, containing a mixture of fresh and salt water (brackish water).

Moons

Natural satellites that revolve around a more massive body because they are caught by a gravitational pull.

Comets

Large bodies of ice, gas, rock, and dust that travel around the sun in an elliptical orbit, often called "dirty snowballs."

Asteroids

Pieces of rock made of minerals similar to those on rocky planets, mostly found in a belt between Mars and Jupiter.

Astronomical Unit (AU)

A measurement of $150$ million kilometers, representing the average distance from the Earth to the sun.

Rotation

The spinning of an object on its axis.

Revolution

The travel of an object in a path around another object, such as the Earth's year-long path around the sun.

Spring Tides

Strongest gravitational forces occuring when the moon and sun are aligned, resulting in extremely high or low water levels during New and Full Moons.

Neap Tides

Weaker tides occurring when the moon and the sun are not aligned, during the 1st and 3rd Quarter Moons.

Heliocentric Model

The understanding that the sun is at the center of the Solar System, supported by Copernicus and Galileo.

Cell Theory

The theory stating all living things are composed of cells, cells are the smallest unit of life, and living cells come only from other living cells.

Mitochondria

Cell structures that break down sugar molecules to provide energy.

Chloroplasts

Plant cell organelles containing chlorophyll that use energy from the sun to make food (glucose) via photosynthesis.

Mitosis

The division of the nucleus producing two identical daughter cells for growth and repair.

Meiosis

The production of sperm and egg cells (gametes) that carry half the genetic material of the parent.

Unicellular

Organisms made up of only one cell (prokaryotes).

Multicellular

Organisms made of more than one cell.

Binomial nomenclature

A formal system of naming organisms developed by Carolus Linnaeus, consisting of the genus and the species names.

Genotype

The sum total of an organism's genes, representing its genetic make-up.

Phenotype

The characteristics of an organism that show up in its appearance, influenced by genetics and environment.

Alleles

Different forms of genes that can be either dominant or recessive.

Natural Selection

The process proposed by Charles Darwin where individuals best adapted to their environment are most likely to survive and reproduce ("survival of the fittest").

pH scale

A scale measuring hydrogen ion concentration ranging from $0$ to $14$, where less than $7$ is acidic, $7$ is neutral, and greater than $7$ is basic.

Neutralization Reaction

A chemical reaction between an acid and a base that produces a salt and water.

Ionic bond

A chemical bond created when atoms transfer electrons, resulting in oppositely charged ions that attract one another.

Covalent bond

A chemical bond formed when atoms with similar electronegativity share electrons.

Longitudinal waves

Waves like sound where oscillations are along the same direction as the direction of travel, showing areas of compression and rarefaction.

Refraction

The bending of waves and change in speed as they pass from one medium to another.

Law of Reflection

The principle stating that the angle at which waves approach a barrier equals the angle at which they reflect off the barrier.

Convex lenses

Lenses that converge or focus light rays.

Concave lenses

Lenses that diverge or spread out light rays.

Newton’s First Law of Motion

The law stating that an object at rest stays at rest and an object in motion stays in motion unless acted upon by a force.

Newton’s Second Law of Motion

The law stating that Force equals mass times acceleration ($F = ma$).

Newton’s Third Law of Motion

The law stating that for every action (force) there is an equal and opposite reaction (force).

Weight

A measure of the force due to gravity acting on a mass, measured in newtons.

Work

The product of force and distance ($W = F \times d$), done when an object moves in the direction of the applied force.

Resistance

A property of matter that affects the flow of electricity through a system.

Electric motor

A device that converts electrical energy into physical movement (mechanical energy).

Electric generator

A device that converts mechanical energy into electrical energy using induction.