Science 8/9 Finals

Independent variable

The variable that stands alone and is not affected by other factors.

Dependent variable

The variable that is influenced by another factor; result of an independent variable.

Control variable

An element that remains unchanged throughout an experiment.

Constants

Variables that stay the same and cannot be controlled directly.

Electromagnetic radiation

Energy that travels in waves and includes visible light.

Speed of light

The speed at which light travels, approximately 3.00 x 10^8 m/s.

Ray model of light

Theory stating that light travels in straight lines.

Ray diagrams

Diagrams that show the path of light through different mediums.

Crest

The highest point of a wave.

Trough

The lowest point of a wave.

Wavelength

The distance between two matching points on a wave.

Amplitude

The height of a wave above or below its rest position.

Frequency

The number of wavelengths that pass a point in one second, measured in hertz (Hz).

Period

The time it takes for one complete cycle of a wave to pass.

Transverse waves

Waves that move up and down, like waves on a rope.

Compression waves (P waves)

Waves that move back and forth, like a spring.

Lens

A curved optical device that bends light.

Concave lens

A lens that is thinner in the center and causes light to diverge.

Convex lens

A lens that is thicker in the center and causes light to converge.

Focal point

The point where parallel rays of light converge or appear to originate from.

Focal length

The distance from the focal point to the center of the lens.

Magnifying glass

An optical device that uses a convex lens to create an enlarged image.

Virtual image

An image that cannot be projected onto a screen; seen by looking through an optical device.

Reflection

The bouncing back of light when it hits a smooth surface.

Law of Reflection

The principle stating that the angle of incidence equals the angle of reflection.

Plane mirror

A flat mirror that reflects light evenly.

Concave mirror

A mirror that curves inward and can magnify images.

Convex mirror

A mirror that curves outward and causes images to appear smaller.

Refraction

The bending of light rays as they pass from one medium to another.

Myopia

Nearsightedness; a condition where distant objects appear blurry.

Hyperopia

Farsightedness; a condition where close objects appear blurry.

Astigmatism

An eye condition caused by an imperfectly shaped cornea.

Laser eye surgery

A procedure to reshape the cornea to correct vision.

Cones

Photoreceptor cells in the retina that detect color.

Color blindness

A condition where a person cannot distinguish certain colors.

Visual acuity

The clarity or sharpness of vision, commonly measured as 20/20 vision.

Blind spot

An area in the visual field that cannot detect light.

Aqueous humor

The transparent fluid that maintains ocular pressure in the eye.

Cornea

The clear outer layer of the eye that refracts light.

Pupil

The opening in the center of the iris that allows light to enter the eye.

Retina

Light-sensitive tissue at the back of the eye that converts light into electrical signals.

Rods

Photoreceptor cells in the retina responsible for vision in low light.

Sclera

The white outer layer of the eye that provides structure.

Vitreous humor

The clear, jelly-like substance filling the space between the lens and the retina.

Tapetum

A reflective layer in the eyes of some animals that enhances night vision.

Kinetic Molecular Theory

Theory stating that matter is made of tiny particles in constant motion.

Atomic theory

The scientific theory that matter is composed of atoms.

Proton

A positively charged particle found in the nucleus of an atom.

Neutron

A neutral particle found in the nucleus of an atom.

Electron

A negatively charged particle that orbits the nucleus of an atom.

Periodic table

A table organizing elements according to their atomic number and properties.

Density

The mass per unit volume of a substance, typically measured in g/cm³.

Displacement

A method used to measure the volume of irregularly shaped objects.

Quarks

Elementary particles that make up protons and neutrons.

Leptons

A family of particles that includes electrons.

Cell membrane

The protective layer surrounding the cell that regulates movement of substances.

Cytoplasm

The jelly-like fluid inside a cell where organelles are located.

Cell wall

A rigid layer surrounding plant cells that provides structure.

Organelle

Specialized structures within a cell that perform specific functions.

Chloroplasts

Organelles in plant cells that capture light energy for photosynthesis.

Mitochondria

The powerhouse of the cell, producing energy from food molecules.

Ribosomes

Cellular structures that synthesize proteins.

Endoplasmic reticulum

Network of membranes involved in the production and transport of proteins and lipids.

Lysosomes

Organelles that contain digestive enzymes to break down waste.

Golgi apparatus

An organelle that modifies, sorts, and packages proteins and lipids.

Binary fission

A type of asexual reproduction where a single organism divides into two identical cells.

Budding

A form of asexual reproduction where a new organism grows off the parent.

Meiosis

The process of cell division that produces gametes with half the number of chromosomes.

Zygote

The fertilized egg that results from the union of sperm and egg.

Gametes

Haploid reproductive cells, such as sperm and egg.

DNA

Deoxyribonucleic acid, the molecule that carries genetic information.

Chromosome

A structure within cells that contains DNA and genetic information.

Mutation

A change in DNA that can affect gene function.

Insulators

Materials that do not allow electric charges to flow easily.

Conductors

Materials that allow electric charges to flow easily.

Static charge

An electrical charge that accumulates on an object.

Electric circuit

A pathway that allows current to flow.

Voltage

The measure of electric potential difference between two points in a circuit.

Current

The flow of electric charge, measured in amperes (A).

Ohm's Law

The principle relating voltage, current, and resistance, stating V=IR.

Seismic waves

Waves of energy that travel through the Earth, produced by earthquakes.

Volcano

An opening in the Earth's surface through which molten rock, ash, and gases escape.

Earthquake

The shaking of the ground caused by a sudden release of energy in the Earth's crust.

Tectonic plates

Large plates that make up the Earth's surface and move over the semi-fluid mantle.

Subduction

The process where one tectonic plate moves under another and sinks into the mantle.

Albedo

The fraction of solar energy reflected from the Earth back into space.

Greenhouse effect

The trapping of heat by greenhouse gases in the Earth's atmosphere.

Climate change

Long-term changes in temperature and typical weather patterns.

Global warming

An increase in Earth's average surface temperature due to rising levels of greenhouse gases.

Carbon cycle

The cycle through which carbon is exchanged among the atmosphere, land, ocean, and biosphere.

El Nino

A climate pattern characterized by warming ocean temperatures in the Pacific, affecting weather globally.

La Nina

A climate pattern characterized by cooling ocean temperatures in the Pacific.

Electromagnetic spectrum

The range of all types of electromagnetic radiation.

Visible light

The portion of the electromagnetic spectrum that is visible to the human eye.

Photosynthesis

The process by which green plants use sunlight to synthesize nutrients from carbon dioxide and water.

Cellular respiration

The process in which cells convert sugars and oxygen into energy, carbon dioxide, and water.

Antigens

Substances that induce an immune response, often found on the surface of pathogens.

Vaccine

A preparation used to stimulate an immune response against a specific disease.

Aerosol

Suspended particles or droplets in the air, often used in sprays.

Ozone layer

A region of Earth's stratosphere that absorbs most of the Sun's harmful ultraviolet radiation.