NB G6 Science key terms

Information gathered directly through the senses or with instruments, such as noting that a plant's leaves are yellow. Observations may be qualitative descriptions or quantitative measurements and form the evidence for scientific claims.

A logical explanation or conclusion drawn from observations and prior knowledge, such as guessing that yellow leaves mean too little water. Inferences go beyond what was directly seen and must be supported by evidence.

A testable, tentative statement predicting what will happen under certain conditions, often written as an if-then prediction. A good hypothesis can be supported or rejected by evidence collected in a controlled investigation.

Any factor in an investigation that can change or be changed, such as temperature, amount of light, or time. Scientists identify variables so they can control them and measure their effects accurately.

An investigation in which all conditions stay the same except the one factor being tested. This design lets scientists attribute changes in results to the tested factor rather than to other influences.

A quantitative observation expressed as a number with a unit, such as 12 centimeters or 25 degrees Celsius. Accurate measurement allows comparisons, data analysis, and repetition by other investigators.

Recorded observations and measurements collected during an investigation, often organized in tables, charts, or graphs. Patterns in data help scientists decide whether a hypothesis is supported.

Running the same test multiple times to reduce the effect of random error and increase confidence in results. Consistent results across trials suggest the findings are reliable rather than accidental.

A judgment about whether the evidence supports the hypothesis, based on analyzed data. Conclusions may also suggest improvements to the investigation or new questions to explore.

An organism that makes its own food, usually through photosynthesis, using sunlight, water, and carbon dioxide. Producers such as plants and algae form the base of food chains and supply energy to other organisms.

An organism that cannot make its own food and must eat other organisms for energy. Consumers include herbivores that eat plants, carnivores that eat animals, and omnivores that eat both.

An organism such as a fungus or bacterium that breaks down dead plants and animals, releasing nutrients back into the soil. Decomposers recycle matter and keep ecosystems from piling up waste.

A series of organisms in which each is eaten by the next, showing one path that energy and matter travel. Arrows point from the organism eaten toward the one that eats it.

A diagram of many overlapping food chains that shows how organisms in an ecosystem are connected. Food webs better represent real feeding relationships than a single chain does.

All the living organisms in an area together with the nonliving parts, such as soil, water, air, and sunlight, interacting as a system. Ecosystems can be small, like a pond, or very large.

All the members of one species living in the same area at the same time, such as all the frogs in a pond. Populations interact with other populations to form a community.

The particular place where an organism lives and finds the food, water, shelter, and space it needs. Different organisms are suited to different habitats.

A trait or behavior that helps an organism survive and reproduce in its environment, such as thick fur in cold climates. Adaptations develop over many generations through natural selection.

The process by which organisms with helpful inherited traits tend to survive and reproduce more, so those traits become more common over generations. It explains how populations adapt to their surroundings.

The process by which green plants, algae, and some bacteria use sunlight energy to combine water and carbon dioxide into sugar, releasing oxygen. It stores energy in food and supplies oxygen to ecosystems.

The process in cells that releases energy from sugar by combining it with oxygen and producing carbon dioxide and water. It powers life activities and works in a cycle with photosynthesis.

The smallest unit of life that can carry out basic life functions. Some organisms consist of a single cell, while others, including plants and animals, are made of many cells.

A body part made of different tissues working together for a specific function, such as the heart, lungs, or leaves of a plant. Organs cooperate within organ systems.

A group of organs that work together to perform a major function, such as the digestive system or circulatory system. Systems interact to keep an organism healthy and functioning.

A group of similar cells that work together to do a particular job, such as muscle tissue or the outer layers of a leaf. Tissues combine to form organs.

A characteristic passed from parents to offspring through genetic material, such as eye color or flower color. Inherited traits differ from learned or acquired traits, which come from experience or environment.

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

The amount of matter in an object, usually measured in grams or kilograms. Mass stays the same regardless of location, unlike weight, which depends on gravity.

The amount of space an object or substance occupies, often measured in milliliters, liters, or cubic centimeters. Volume of irregular solids can be found by water displacement.

How much mass is packed into a given volume, calculated as mass divided by volume. Objects less dense than water float, while denser objects sink.

A characteristic that can be observed or measured without changing the substance into a different substance, such as color, density, melting point, or hardness. Physical properties help identify materials.

A characteristic describing how a substance reacts with other substances, such as rusting, burning, or reacting with acid. Observing a chemical property produces a new substance.

A change in which one or more new substances form, often shown by color change, gas production, heat release, or a new smell. Rusting and burning are examples.

A change in size, shape, state, or appearance that does not create a new substance, such as melting ice or tearing paper. The material's identity stays the same.

A push or pull that can change an object's motion, direction, or shape, measured in newtons. Forces act in pairs and can be balanced or unbalanced.

A change in an object's position compared with a reference point over time. Motion is described using distance, direction, and speed.

The distance an object travels in a given amount of time, calculated as distance divided by time. Speed tells how fast position changes but not in which direction.

A force that resists motion when two surfaces rub against each other, producing heat and slowing objects. Rough surfaces create more friction than smooth ones.

The ability to cause change or do work. Energy exists in forms such as motion, light, heat, sound, and stored chemical energy, and it can transfer between objects.

The energy an object has because of its motion. A faster or more massive moving object has more kinetic energy than a slower or lighter one.

Stored energy an object has because of its position or condition, such as a ball held high above the ground or energy stored in food and batteries. It can convert into kinetic energy.

The continuous movement of water among Earth's oceans, atmosphere, and land through evaporation, condensation, precipitation, and collection. It redistributes fresh water and shapes weather and climate.

The process in which a liquid gains energy and changes into a gas at its surface, such as water turning into water vapor. Evaporation is a key step of the water cycle.

The process in which a gas loses energy and changes into a liquid, such as water vapor forming droplets on a cold glass. Condensation forms clouds and dew.

The movement of weathered rock and soil from one place to another by water, wind, ice, or gravity. Erosion can reshape landforms and deposit sediment elsewhere.

The breakdown of rocks and other materials into smaller pieces through processes such as freezing water, plant roots, wind, or chemical reactions. Weathered material may later be eroded away.

The dropping or settling of eroded sediment in a new location, such as sand building up at a river bend or on a beach. Deposition builds new landforms over time.

Small pieces of rock, sand, silt, or clay that have been broken down and moved by water, wind, or ice. Sediment may settle in layers and eventually form sedimentary rock.

The curved path an object follows as it revolves around another object because of gravity, such as Earth's yearly path around the Sun. Orbits can be nearly circular or elliptical.

The spinning of an object on its own axis. Earth's rotation once about every 24 hours causes day and night.

The movement of one object around another, such as Earth traveling around the Sun once each year. Revolution, together with Earth's tilt, causes the seasons.

A force of attraction between objects that have mass. Gravity keeps planets in orbit around the Sun and pulls objects toward Earth's surface.

The apparent shape of the Moon as seen from Earth, changing in a repeating cycle as the Moon orbits Earth and sunlight strikes different portions of its surface. Phases include new, crescent, quarter, and full.

The Sun and all the objects that orbit it, including eight planets, their moons, dwarf planets, asteroids, and comets. Gravity holds the system together.

Any human-made tool, system, or process designed to solve a problem or meet a need, ranging from simple tools to complex machines and computers. Technology is developed and improved through engineering.

A step-by-step process for solving problems that includes defining a need, brainstorming solutions, building a model, testing it, and improving it. It uses scientific knowledge and often repeats until a solution works well.

A first working model of a design built to test ideas and find problems before making a final product. Prototypes are often revised several times based on test results.

A material or energy source found in nature that people use, such as water, soil, timber, minerals, and sunlight. Some resources are renewable, while others are limited.

A natural resource that can be replaced or replenished within a reasonable time, such as sunlight, wind, or trees that are replanted. Using renewable resources can reduce harm to the environment.

The careful use and protection of natural resources so they last longer and stay healthy, such as reducing waste, recycling, and saving water. Conservation helps keep ecosystems balanced for the future.