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Science Final Vocab
This is the vocabulary for the 8th grade Science Final
Term | Definition |
---|---|
Force | A push or pull exerted on an object |
Friction | The force that two surfaces exert on each other when they rub against each other; the transfer of electrons from one uncharged object to another uncharged object by rubbing. |
Weight | a measure of the force of gravity acting on an object |
Speed | The distance an object travels per unit of time |
Velocity | Speed in a given direction |
Acceleration | the rate at which velocity changes |
Sliding Friction | Friction that occurs when one solid surface slides over another |
Rolling Friction | Friction that occurs when an object rolls over a surface |
Static Friction | Friction that acts between objects that are not moving |
Fluid Friction | Friction that occurs as an object moves through a fluid |
Work | Work = Force * distance |
Power | Power = work/time |
Gravitational Potential Energy | Gravitational potential energy is energy an object possesses because of its position in a gravitational field. |
Kinetic Energy | Energy that object has due to its motion |
Altitude | Elevation above sea level |
Weather | The condition of Earth's atmosphere at a particular time and place |
Atmosphere | The relatively thin layer of gases that form Earth's outermost layer |
Water vapor | water in the form of a gas |
Electromagnetic radiation | The energy transferred through space by electromagnetic waves |
UV rays | Electromagnetic waves with wavelengths that are shorter than visible light but longer than X-rays |
Infrared Radiation | Electromagnetic waves with wavelengths that are longer than visible light but shorter than microwaves |
Greenhouse effect | The trapping of heat near a planet's surface by certain gases in the planet's atmosphere |
Scattering | Reflection of light in all directions |
Optical Telescope | A telescope that uses lenses or mirrors to collect and focus visible light |
Nonoptical Telescope | A telescope that collects and focuses different types of electromagnetic radiation |
Parallax | The apparent change in position of an object when seen from different places |
Lightyear | The distance that light travels in one year, about 9.5 trillion kilometers |
Penumbra | The part of a shadow surrounding the darkest part |
Umbra | The darkest part of a shadow |
Newton's First Law | Inertia; an object in motion will stay in motion, an object at rest will stay at rest unless acted upon by an outside unbalanced force |
Newton's Second Law | F=ma; the acceleration of an object as produced by a net force is proportional to the magnitude of the net force and inversely proportional to the mass of the object |
Newton's Third Law | for every action there is an equal and opposite reaction |
Thermosphere | Top layer of atmosphere; aurora borealis |
Mesosphere | Second to top layer of atmosphere; Catches meteors |
Stratosphere | Second to bottom layer of the atmosphere; planes; weather |
Troposphere | Bottom layer of the atmosphere; we live here |
Ionosphere | Bottom layer of the Thermosphere |
Exosphere | Top layer of the Thermosphere. |
Mercury Barometer | Measures air pressure with a bowl of mercury. Air pressure pushes the mercury down and it rises up a tube with a vacuum at the top. |
Aneroid Barometer | cylindrical device that measures air pressure and indicates it by moving a needle |
EM Spectrum | Radio Waves, Microwaves, Infrared Radiation, Visible Light, Ultraviolet Radiation, X-rays, Gamma Rays |
What causes wind? | a difference in air pressure |
Classification of stars | Temperature; Composition, Size, Brightness, Color |
H-R diagram compares.... | Temperature and Brightness |
Formation of a star | Contracting dust and gas --> Nuclear fission --> Protostar |
Lifespan of a star | Less mass --> Longer lifespan, and vice versa |
Death of a low mass star | Star --> Expands to red giant --> outer layers drift away: white dwarf |
Death of a high mass star | Star --> Supergiant --> explodes to supernova --> can form a neutron star (spinning = pulsar) |
Spiral Galaxy | Disc shaped; bulge at middle; arms contain dust, gas, stars |
Elliptical Galaxy | Round; no arms; little gas or dust |
Irregular | Smaller; young stars; lots of gas and dust; no identifiable shape |
Big Bang Theory | The universe formed in an instant billions of years ago. It is expanding forever |
Hubble's Law | Evidence for big bang; Discovered by Edwin Hubble; Farther away galaxies are, the faster they are moving away |
Cosmic Radiation | Evidence for big bang; discovered by arno penzias and robert wilson; picked up leftover thermal energy from the big bang |
Reasons for the Seasons | God; tilt of axis; Earth's revolution around the sun; Parts of earth receive more direct sunlight than others |