OST Grade 5 Science key terms

The carrying away of weathered rock, soil, or sediment by moving water, wind, ice, or gravity. It shapes valleys, moves beaches, and can remove valuable topsoil from farmland.

The breaking down of rocks and other materials at Earth's surface into smaller pieces. It can happen by physical means, such as freezing water splitting rock, or by chemical means, such as acid slowly dissolving limestone.

The dropping of eroded sediment when moving water, wind, or ice slows down or melts. Deposited material builds deltas, sand dunes, and layers of sedimentary rock over time.

Loose bits of rock, sand, silt, clay, or shell material that have been broken down and moved from their original place. Sediment settles in layers and may later harden into sedimentary rock.

Rock formed when layers of sediment are pressed and cemented together over long periods. Because it forms in layers, it often contains fossils that reveal what past environments were like.

The preserved remains or trace of a living thing, such as a bone, shell, leaf print, or footprint, usually found in sedimentary rock. Fossils give evidence about organisms and environments of the past.

The mixture of weathered rock particles, decayed plant and animal material, air, and water that covers much of Earth's land surface and supports plant growth. Its composition varies with climate and the rock beneath it.

The continuous movement of water among Earth's oceans, atmosphere, and land through evaporation, condensation, precipitation, and collection. The same water is recycled again and again through these processes.

The change of a liquid into a gas, which happens when water gains enough energy, usually from heat. In the water cycle, evaporation from oceans and lakes moves water vapor into the air.

The change of a gas into a liquid, which happens when vapor cools. In the water cycle it forms clouds and fog, and on a cold glass it forms droplets of water.

Water that falls from clouds to Earth's surface as rain, snow, sleet, or hail. It returns water that evaporated from oceans and land back to the ground.

The release of water vapor into the air from the leaves of plants. It is part of the water cycle and can add large amounts of moisture to the atmosphere over forests and croplands.

A natural resource that can be replaced or replenished by natural processes within a human lifetime, such as sunlight, wind, flowing water, and trees. Even renewable resources can be used up if they are consumed faster than they are replaced.

A natural resource that exists in limited amounts and cannot be replaced quickly, such as coal, oil, natural gas, and minerals. Once these are used, they are gone for practical purposes.

The careful use and protection of natural resources so they are not wasted or destroyed. It includes reducing use, reusing materials, recycling, and protecting habitats and water supplies.

All the living organisms in an area together with the nonliving parts of their environment, such as water, soil, air, and sunlight. Organisms and their surroundings interact and depend on one another.

An organism that makes its own food, usually by photosynthesis, using sunlight, water, and carbon dioxide. Plants, algae, and some bacteria are producers and form the base of most food chains.

An organism that cannot make its own food and must eat other organisms to get energy. Consumers may eat producers or other consumers and are grouped as herbivores, carnivores, or omnivores.

An organism, such as many fungi and bacteria, that breaks down dead plants and animals and returns nutrients to the soil. Decomposers recycle matter so it can be used again by producers.

A model showing the path of energy from one organism to the next as each is eaten by another, usually beginning with a producer. Arrows show the direction in which energy flows.

A diagram of several connected food chains that shows how organisms in an ecosystem feed on one another. It is a more realistic picture of feeding relationships than a single food chain.

The process by which green plants, algae, and some bacteria use sunlight, water, and carbon dioxide to make sugar and release oxygen. It is the main way energy from the Sun enters living systems.

A feature or behavior that helps an organism survive and reproduce in its environment, such as a thick coat in cold climates or camouflage. Adaptations develop in populations over many generations.

The particular place where an organism lives and finds the food, water, shelter, and space it needs. Different habitats, such as a pond or a forest, support different communities of organisms.

All the members of one species that live in the same area at the same time. Population size can change when food, water, space, or predators become more or less available.

The breakdown of dead organisms and wastes into simpler substances by decomposers such as bacteria and fungi. It releases nutrients into the soil so producers can use them again.

Anything that has mass and takes up space. Matter exists as solids, liquids, and gases and is made of particles too small to see with the naked eye.

A measure of the amount of matter in an object, usually measured in grams or kilograms with a balance. Mass stays the same when an object changes shape or location, unlike weight.

The amount of space that matter takes up, often measured in milliliters or cubic centimeters. For a solid object, volume can be found by measuring how much water it displaces.

A state of matter that has a definite shape and a definite volume because its particles are packed closely and vibrate in place. A solid keeps its shape unless a force changes it.

A state of matter that has a definite volume but takes the shape of its container because its particles can slide past one another. Liquids flow and form a flat surface at rest.

A state of matter that has no definite shape or volume because its particles spread out to fill any container. A gas can be compressed and expands when heated.

A combination of two or more substances that are physically mixed but not chemically joined, such as trail mix or salt water. Each substance keeps its own properties and can often be separated again.

A mixture in which one substance dissolves evenly in another, such as sugar dissolved in water. The dissolved substance is spread throughout and does not settle out.

The transfer of heat through direct contact between materials, as when a metal spoon in hot soup becomes hot. Energy moves from the warmer object to the cooler one.

The transfer of heat by the movement of a liquid or gas, in which warmer, less dense material rises and cooler material sinks. It drives boiling water currents and many weather patterns.

The ability to cause change or do work. It exists in forms such as motion, light, heat, sound, and stored chemical energy, and it can change from one form to another but is not created or destroyed.

A complete, closed path through which electric current can flow, usually including a power source, wires, and a device such as a bulb. If the path is broken, the current stops.

A testable prediction or possible explanation for an observation, stated clearly enough that an investigation could support or contradict it. It is often written as an if-then statement before an experiment begins.

Any factor in an investigation that can change or be changed. A fair test changes only one variable at a time while keeping all the others the same.

Information gathered by using the senses or by measuring with tools, such as noting a plant's height or the color of a liquid. Observations are the evidence on which scientific explanations are built.

The measurements, counts, and recorded observations collected during an investigation. Data are often organized in tables and graphs so patterns can be seen and interpreted.

A judgment about what the results of an investigation mean, based on the evidence collected and related back to the hypothesis. A good conclusion states whether the data supported the prediction and why.