Grade 8 Science Study Pack Flashcards

Flashcards for Grade 8 Science Study Pack

Wave

A disturbance that carries energy from one place to another.

Mechanical Wave

Needs a medium (solid, liquid, or gas) to travel.

Electromagnetic Wave

Can travel through space (no medium needed).

Transverse Wave

Particles move up and down, energy moves forward; movement is perpendicular (90°).

Crest

Highest point of the wave.

Trough

Lowest point of the wave.

Wavelength

Distance from one crest to the next.

Amplitude

Height from the rest position to the crest/trough—shows energy.

Longitudinal Wave

Particles move back and forth. Energy and particle movement are in the same direction.

Compression

Area where particles are close together.

Rarefaction

Area where particles are spread out.

Amplitude

Height of the wave; more amplitude = more energy.

Wavelength

Length of one full wave (crest to crest or compression to compression).

Frequency

Number of waves passing a point in one second; more frequency = more energy.

Wave

A movement that carries energy.

Medium

Material the wave travels through.

Transverse Wave

Wave with up and down particle movement.

Longitudinal Wave

Wave with back and forth movement.

Amplitude

Wave height – shows energy.

Wavelength

Length of one wave cycle.

Frequency

Number of waves per second.

Compression

Particles close together.

Rarefaction

Particles spread apart.

Reflection

The wave bounces off the surface.

Absorption

The wave’s energy is taken in by the material.

Transmission

The wave passes through the material.

Refraction

The wave bends as it changes material.

Specular Reflection

Light bounces in one direction; happens on smooth surfaces.

Diffuse Reflection

Light bounces in many directions; happens on rough surfaces.

Transparent

Lets all light through clearly.

Translucent

Lets some light through, but not clear.

Opaque

Blocks all light.

Specular reflection

Clear reflection in one direction (mirror).

Diffuse reflection

Scattered reflection in many directions (wall).

Normal line

90° line used to measure angles of reflection/refraction.

Sound wave

A mechanical wave that carries sound.

Signal

A way to send information using a wave.

Analog Signal

Smooth and continuous signals; can have any value (infinite points); more affected by noise.

Digital Signal

Made of steps (only 0s and 1s); clearer and easier to copy, save, and send; less affected by noise

Bit

A single unit of digital information (0 or 1).

Signal

A wave that carries information.

Analog signal

A smooth signal that changes continuously.

Digital signal

A stepped signal made of 0s and 1s.

Noise

Unwanted changes/errors in a signal.

Transmission

Sending a signal or message.

Communication

Sending information from one place to another.

Device

A machine or tool used to send or receive data.

Rotation

Spinning in place.

Revolution

Moving around another object.

Tilt

The angle of Earth’s axis.

Eclipse

When light is blocked by one object passing another.

Solar eclipse

Moon blocks sunlight from Earth.

Lunar eclipse

Earth blocks sunlight from the Moon.

Umbra

Darkest part of a shadow (total eclipse).

Penumbra

Lighter part of a shadow (partial eclipse).

Waxing

Moon appears to grow.

Waning

Moon appears to shrink.

Phase

The visible shape of the Moon from Earth.

Gravity

A force that pulls objects toward each other.

Mass

How much matter something has.

Orbit

The curved path one object takes around another.

Force

A push or a pull.

Attract

To pull something closer.

Planet

A large object that goes around a star.

Moon

The natural object that orbits Earth.

Star

A big ball of hot gas like the Sun.

Solar System

The Sun and all the objects that orbit it.

Scale Model

A smaller version to help show real size or distance.

Terrestrial Planet

A small, rocky planet near the Sun.

Gas Giant

A very big planet made mostly of gas.

Ice Giant

A large, cold planet made of gas and ice.

Asteroid

A small rocky object in space.

Asteroid Belt

A region between Mars and Jupiter with many asteroids.

Diameter

The width of a round object.