Science semester 2 final

Magma

Hot, melted rock found under Earth's surface.

Lava

Magma that has reached the surface and is flowing out of a volcano.

Mineral

A natural, solid substance with a certain chemical makeup, like quartz or salt.

Rock

A solid material made of minerals.

Grains

Small pieces or particles that make up a rock.

Weathering

The breaking down of rocks into smaller pieces by wind, water, or other forces.

Erosion/Deposition

Erosion is the movement of rock pieces by water, wind, or ice. Deposition is when those pieces get dropped in a new place.

Pangaea

A supercontinent that included all Earth's land long ago before it split apart.

Seafloor spreading

New ocean floor forms as magma rises and pushes old seafloor away at mid-ocean ridges.

Plate Tectonics

A theory that Earth's outer layer is made of big pieces (plates) that move.

Continental Drift Hypothesis

The idea that continents slowly move across Earth's surface.

Alfred Wegener

The scientist who proposed the continental drift idea.

Convergent plate boundary

A place where two plates move toward each other (can form mountains or cause volcanoes).

Divergent plate boundary

A place where two plates move away from each other (often seen at mid-ocean ridges).

Transform plate boundary

A place where two plates slide past each other (often causes earthquakes).

Tension

A force that pulls rocks apart.

Compression

A force that pushes rocks together.

Shear

A force that causes rocks to slide past each other.

Isostasy

A balance between Earth's crust and the mantle that keeps the crust floating.

Convection

Movement of hot material rising and cooler material sinking, like boiling soup (happens in Earth's mantle).

Slab Pull

When a heavy, sinking tectonic plate pulls the rest of the plate down with it.

Basal Drag

Friction from the moving mantle that drags the plate above it.

Ridge Push

When new rock at a mid-ocean ridge pushes older rock away, helping move tectonic plates.

Subduction

When one plate slides under another and sinks into the mantle.

Earthquake

A sudden shaking of the ground caused by movement of Earth's plates.

Plate boundaries

The edges where tectonic plates meet.

Faults/fault zone

Cracks in Earth's crust where movement happens.

Epicenter

The point on Earth's surface directly above where an earthquake starts.

S-Waves

Earthquake waves that move slower and shake side to side.

P-Waves

Faster earthquake waves that move in a push-pull motion.

Richter Scale

Measures how strong an earthquake is (how much energy it releases).

Moment Magnitude Scale

A more modern way to measure earthquake strength using size and movement.

Triangulation

A way to find the earthquake's epicenter by using data from three different places.

Spectroscope

A tool that breaks light into colors to show what stars are made of.

Luminosity/absolute magnitude

How bright a star really is.

Apparent Magnitude

How bright a star looks from Earth.

Astronomical unit (AU)

The distance from Earth to the Sun (about 93 million miles).

Light-year

The distance light travels in one year.

Outer Planets

Jupiter, Saturn, Uranus, Neptune (farther from the sun, gas giants).

Inner Planets

Mercury, Venus, Earth, Mars (closer to the sun, rocky planets).

Terrestrial planet

A rocky planet like Earth.

Gas giant

A large planet made mostly of gas, like Jupiter.

Comet

A space object made of ice, dust, and rock that orbits the Sun.

Black hole

A space object with gravity so strong that not even light can escape.

Asteroid

A rocky object orbiting the Sun, mostly in the asteroid belt between Mars and Jupiter.

Constellations

Patterns of stars that people have named.

Galaxy

A huge group of stars, gas, and dust held together by gravity.

Spiral galaxy

A galaxy shaped like a pinwheel (the Milky Way is one).

Elliptical galaxy

A round or oval-shaped galaxy with mostly older stars.

Irregular galaxy

A galaxy with no clear shape.

Milky Way

The spiral galaxy where our solar system is.

Local Group

A group of nearby galaxies, including the Milky Way.

Parallax

The way a star's position appears to change as Earth moves, used to measure distance.

Orbit

The path one object takes around another in space.

Revolution vs. rotation

Revolution is one object going around another (Earth around the Sun); rotation is spinning (Earth spinning on its axis).

Dwarf planets

Small, round planets that orbit the Sun but don't clear other objects from their path (like Pluto).

Engineering practice: Know/Needs to know development

Figuring out what you already know and what you still need to find out to solve a problem.

Engineering practice: Requirements and constraints

Requirements are what your design must do. Constraints are the limits like time, materials, or cost.

Stanford Design Cycle

A process for solving problems: Empathize, Define, Ideate, Prototype, Test, and Improve.

Renewable resources

Can be replaced (solar, wind, water).

Non-renewable resources

Can run out (oil, coal, natural gas).

Beam bridge

Short spans.

Arch bridge

Medium spans, strong with curves.

Suspension bridge

Long spans, uses cables.

Truss bridge

Uses triangles for strength.

Shallow foundation

For smaller buildings.

Deep foundation

For tall/heavy buildings to go into stronger ground.

Earth's position ideal

Earth is just the right distance from the Sun (not too hot or cold). Protected by gas giants from too many asteroid hits. Located in a calm part of the Milky Way (not near a black hole or explosion zones).