8th Grade Science MCAS

Solar Eclipse

The moon blocks the Sun from being visible from the Earth

Lunar Eclipse

The moon is hidden in the Earth's shadow

Causes of Seasons

Earth's tilt and revolution around the Sun affect the amount of direct sunlght. Summer occurs when we are tilted towards the Sun and receive more direct sunlight. Winter occurs when we're tilted away from the sun and receive less direct sunlight.

Galaxy

A collection of gas, dust, and billions of stars held together by gravity.

Planet

An object that orbits a star, is large enough to be made a sphere by gravity, and has cleared its own orbit.

Solar System

A star and all of the planets and other objects that orbit it

Sun

A star at the center of a solar system

Universe

All of space and everything in it

The reason planets orbit the sun

Gravity causes planets to orbit

Transform Boundary

A plate boundary where two plates move past each other in opposite directions

Convergent Boundary

A plate boundary where two plates move toward each other.

Divergent Boundary

A plate boundary where two plates move away from each other.

The top layer of rock is _ compared to the _ layer.

The top layer is newer than the bottom layer. (As new sediment gets laid down on the Earth's surface older rock gets buried deeper and deeper)

Evidence of Plate Movement

Continents fit together, Fossil Evidence, Earthquakes, Volcanoes, Mountain Ranges

What happens when air masses collide

Warm air rises over the cold air. Water vapor in the rising air condenses into water and clouds are formed.

Characteristics of Plants

Multicellular, Eukaryotic, Cell Walls, Make their own food, , most can't move

Characteristics of Animals

Multicellular, Eukaryotic, Heterotrophic (need to eat food), Most take in oxygen, Most are motile, Most have organs

Characteristics of Bacteria

No organelles, Single-Celled, Most are microscopic

Characteristics of Fungi

Multicellular, Eukaryotic, Heterotrophic (need to eat food), Have cell walls, Reproduce sexually & asexually, Most are immobile, Most grow in soil

Reactants and Products of Photosynthesis

Reactants: Light Energy, Carbon Dioxide, Water

Products: Glucose, Oxygen

Reactants and Products of Cellular Respiration

Reactants: Glucose, Oxygen

Products: Energy, Carbon Dioxide, & Water Vapor

Plant Cell

Contains a cell wall, chloroplast and large vacuole; rectangular shape

Animal Cell

Does not have a cell wall or chloroplast and a small vacuole; rounded shape

Digestive System

Breaks down food to distribute energy and nutrients throughout the body

Respiratory System

Brings oxygen into the body. Gets rid of carbon dioxide.

Excretory System

Removes waste from the body

Circulatory System

Uses blood to transport oxygen, waste, nutrients, hormones, heat, etc… around the body

Muscular/Skeletal System

Muscles and bones working together to cause movement and support the body.

Nervous System

Sends messages to and from your brain, responding to stimuli and telling your body what to do.

Fats (Lipids)

Molecules that store energy in your body

Proteins

Molecules that your body uses to build and repair itself

Carbohydrates

Molecules that your body use for energy

Why organisms need food

For energy and growth

Environmental factors that influence the growth of organisms

Temperature and Nutrient Availability

Advantages of Sexual Reproduction

Diversity causes different weaknesses, Weaknesses are not always passed down, Evolution happens easier (in fewer generations)

Advantages of Asexual Reproduction

Saves time and energy, Don't need to find a mate, Beneficial traits are always passed down

Producer

Organism that makes its own food (typically through photosynthesis)

Consumer

An organism that obtains energy by consuming other organisms

Decomposer

Breaks down dead organisms

Change to a Gene

Mutation

Gene

A segment of DNA which tells the cell what protein to make

Allele

One version of a gene (can be dominant or recessive)

Chromosome

Bundles of DNA in the nucleus; make it easier to store DNA

Natural Selection

A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits.

Density

How packed together an objects' molecules are; Mass divided by volume

Solids turn into Liquids and Liquids turn into Gases when…

When heat energy is added

Gases turn into Liquids and Liquids turn into Solids when…

When heat energy is removed

Melting

When a solid turns into a liquid

Evaporation

When a liquid turns into a gas

Condensation

When a gas turns into a liquid

Freezing

When a liquid turns into a solid

When kinetic energy increases…

potential energy decreases

Gravitational Potential Energy

Increases when an object's height increases

Conduction

The direct transfer of heat from one substance to another substance that it is touching.

Convection

The transfer of heat by the movement of a fluid when the hot (less dense) fluid rises and the cooler (more dense) fluid sinks

Radiation

The transfer of heat through waves in space

Element

A pure substance made of only one kind of atom

Molecule

A group of atoms bonded together

Compound

A substance made up of atoms of two or more different elements joined by chemical bonds

Mixture

A combination of two or more substances that are not chemically combined

Amplitude

The distance from a wave's resting point to its peak; the "strength" of a wave

Energy

The sum of a wave's potential and kinetic energy

Frequency

The speed at which a wave repeats

Wavelength

The distance between the peaks in a wave

Absorb

The process in which light is taken into an object and converted into energy

Reflect

The bouncing back of light off a smooth surface

Refract

The bending of light when it travels between surfaces

Transmit

Light passing through an object

Potential Energy

stored energy

Kinetic Energy

energy of motion

Nucleus

Control center of the cell. Contains DNA.

Mitochondria

Powerhouse of the cell; makes energy by cellular respiration

Chloroplast

Organelle found in cells of plants that does photosynthesis

Vacuole

A sac inside a cell that acts as a storage area

Cell Membrane

thin, flexible barrier around a cell; regulates what enters and leaves the cell

Cell Wall

A rigid structure that surrounds the cell membrane and provides support to the cell