HiSET Science flashcards
HiSET Science · 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.
- Hypothesis
- A testable and falsifiable prediction or explanation about a natural phenomenon that can be supported or rejected by evidence from an experiment or observation.
- Independent variable
- The factor that a scientist deliberately changes or manipulates in an experiment to observe whether it affects the outcome being measured.
- Dependent variable
- The factor that is measured or observed in an experiment; it may change in response to the independent variable.
- Control group
- A comparison group in an experiment that does not receive the treatment or receives a standard condition, allowing researchers to isolate the treatment's effect.
- Correlation
- A relationship in which two variables change together; correlation alone does not prove that one variable causes the other to change.
- Scientific theory
- A well-supported explanation of a broad set of observations that has been repeatedly tested and is generally accepted by the scientific community.
- Mean
- The arithmetic average of a set of values, calculated by adding all the values and dividing the sum by the number of values.
- Peer review
- A process in which qualified scientists evaluate another researcher's methods, data, and conclusions before publication to check scientific quality and credibility.
- Newton's second law
- The acceleration of an object equals the net force acting on it divided by its mass, often written as F = ma.
- Speed
- The distance an object travels divided by the time it takes, commonly calculated as speed = distance ÷ time.
- Kinetic energy
- The energy an object has because of its motion; it increases with mass and with the square of speed, calculated as ½mv².
- Density
- The mass of a substance per unit volume, calculated as density = mass ÷ volume; denser objects sink in less dense fluids.
- Atomic number
- The number of protons in an atom's nucleus; it identifies the element and equals the number of electrons in a neutral atom.
- pH scale
- A scale from 0 to 14 that measures acidity or basicity; values below 7 are acidic, 7 is neutral, and above 7 are basic.
- Wave equation
- The relationship wave speed = frequency × wavelength; for a constant speed, higher frequency means shorter wavelength and lower frequency means longer wavelength.
- Conservation of mass
- In a closed system, the total mass before a chemical reaction equals the total mass after the reaction because atoms are rearranged, not created or destroyed.
- Cell theory
- The scientific principle that all living things are made of cells, cells are the basic unit of life, and new cells come from existing cells.
- Photosynthesis
- The process by which plants, algae, and some bacteria use light energy to convert carbon dioxide and water into glucose and oxygen.
- Cellular respiration
- The process by which cells release energy from glucose, using oxygen in aerobic respiration and producing carbon dioxide and water as waste products.
- Mitosis
- A type of cell division that produces two genetically identical daughter cells, usually for growth, repair, and replacement of body cells.
- Meiosis
- A type of cell division that produces four genetically varied haploid gametes, such as sperm or egg cells, with half the chromosome number of the parent cell.
- Natural selection
- The process by which individuals with inherited traits better suited to their environment tend to survive and reproduce more, increasing those traits in later generations.
- Food chain
- A sequence showing how energy and matter pass from producers to consumers and decomposers in an ecosystem, usually with about 10% energy transfer between levels.
- Homeostasis
- The maintenance of stable internal conditions in a living organism, such as temperature and pH, often controlled by negative feedback mechanisms.
- Plate tectonics
- The theory that Earth's lithospheric plates move over the asthenosphere, causing earthquakes, volcanoes, mountain building, and continental drift.
- Rock cycle
- The continuous processes that change rocks among igneous, sedimentary, and metamorphic types through melting, cooling, weathering, erosion, deposition, compaction, and heat or pressure.
- Water cycle
- The movement of water through evaporation, transpiration, condensation, precipitation, and runoff, cycling water between Earth's surface, atmosphere, and living things.
- Axial tilt
- The tilt of Earth's rotation axis, about 23.5 degrees, which causes seasons as different hemispheres receive more direct sunlight during the year.
- Moon phases
- The changing apparent shapes of the Moon caused by the changing angle between Earth, the Moon, and the Sun as the Moon orbits Earth.
- Solar system order
- The planets in order from the Sun are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune; the first four are rocky and the next four are gas or ice giants.
- Earth's atmosphere
- The layer of gases surrounding Earth, mostly nitrogen and oxygen, which protects life from harmful radiation and helps regulate surface temperature.
- Greenhouse effect
- The warming of Earth's surface when atmospheric gases absorb and re-emit infrared radiation, trapping heat that would otherwise escape to space.