USVI NGSS Science Grade 5 flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Particle model of matter

The idea that all matter is made of tiny particles too small to see. This model explains how matter behaves when it is heated, cooled, dissolved, or mixed without disappearing.

Conservation of matter

In a closed system, the total mass of matter stays the same during melting, dissolving, mixing, or a reaction; matter is neither created nor destroyed, only rearranged.

Density

The amount of mass packed into a given volume, calculated as mass divided by volume. A denser material has more mass in the same amount of space.

Evidence of a new substance

Signs that two materials reacted to form a new substance include gas bubbles, a color change, a new smell, a solid forming, or a temperature change not caused by heating.

Gravity

A force that pulls every object toward Earth's center, no matter how heavy the object is or whether it is moving. It also acts between all objects in space.

Air resistance

A force that pushes against objects moving through air and slows them down. In a vacuum with no air, all objects fall at the same rate.

Balanced and unbalanced forces

When forces on an object are balanced, its motion does not change. When they are unbalanced, the object speeds up, slows down, or changes direction.

Mass versus weight

Mass is the amount of matter in an object, measured in grams. Weight measures how strongly gravity pulls on that mass and changes if gravity changes.

Energy transfer

Energy can move from place to place or change from one form to another, such as light energy becoming chemical energy stored in the food a plant makes.

Food energy comes from sunlight

The energy stored in food originally came from sunlight. Plants capture light energy and animals get that energy by eating plants or other animals.

Forms of energy

Energy appears as motion, light, sound, heat, electric current, and chemical energy. When energy transfers, some of it usually becomes heat that spreads out.

What plants need to grow

Plants need light, water, air, and minerals. They make their own food in their leaves, and most of the material that makes a plant grow comes from water and air.

Plant structures and functions

Roots take in water and minerals, stems carry materials up and down the plant, and leaves capture the sunlight used to make food.

Photosynthesis

The process in which plants use light energy, water, and carbon dioxide from the air to make their own food, releasing oxygen as a product.

Food web

A model of the feeding relationships in an ecosystem, where arrows show the direction energy flows from the organism being eaten to the organism that eats it.

Decomposers

Organisms such as fungi and bacteria that break down dead plants and animals and animal wastes, releasing nutrients back into the soil for producers to use again.

Producers

Organisms, mainly green plants and algae, that make their own food using sunlight. They are the first source of energy for the rest of a food web.

Effects of removing an organism

Removing one organism affects the whole food web. A population with no predator can grow until its food runs short, then decline.

Day and night

Earth spins on its axis once about every 24 hours. The side facing the Sun has daytime, and the side facing away from the Sun has nighttime.

Shadow length

Shadows are long in early morning and late afternoon and shortest near noon, because shadow length depends on how high the Sun appears in the sky.

Stars are distant suns

Stars look like tiny points of light because they are extremely far away. The Sun is a star that looks large and bright only because it is much closer to Earth.

Cause of seasons

Earth's tilted axis combined with its yearly orbit changes how high the Sun appears and how long daylight lasts, producing seasonal patterns.

Earth's four spheres

Earth's systems are the geosphere of rock and land, the hydrosphere of water, the atmosphere of air, and the biosphere of living things; they constantly exchange matter.

Water cycle

Water moves through evaporation, condensation, precipitation, and runoff, driven by energy from the Sun and repeated endlessly among the ocean, air, and land.

Distribution of Earth's water

Most of Earth's water is salty ocean water. Only a small share is fresh water, and much of that fresh water is frozen in glaciers and ice caps.

Erosion

The moving of weathered rock and soil by water, wind, or ice. Erosion can carve valleys and carry material that settles somewhere else as deposition.

Renewable resource

A resource such as sunlight, wind, or flowing water that natural processes replace within a human lifetime. Coal, oil, and minerals are nonrenewable.

Human effects on environments

Activities such as clearing forests, building roads, farming, and releasing waste can change the water, air, soil, and organisms living in an area.

Conserving resources

Reducing, reusing, and recycling materials lowers the amount of natural resources taken from the environment and the amount of waste left behind.

Criteria and constraints

Criteria are what a design must do to be successful. Constraints are the limits on a design, such as time, cost, available materials, safety, and space.

Engineering design process

Engineers define a problem, brainstorm solutions, build and test a model, evaluate the results, then improve the design through repeated cycles of testing and revision.

Fair test

A test in which only one variable is changed while all other conditions stay the same, so results from different designs can be compared reliably.