PSSA Grade 5 Science cheat sheet

Scientific inquiry is a flexible cycle: ask a question, form a hypothesis, plan and run an investigation, collect and analyze data, draw conclusions, and communicate results.

The independent variable is the factor the experimenter purposely changes; the dependent variable is the factor measured in response to that change.

Controlled variables are factors held the same in every trial so they cannot influence the outcome.

A hypothesis must be testable and falsifiable; evidence can support or reject it, but never proves it absolutely.

Quantitative data are numbers with units (mass 12 g, length 5 cm); qualitative data are descriptions such as color, texture, or odor.

An observation is made with the senses or a measurement tool; an inference is an interpretation built from observations plus prior knowledge.

Repeating trials and using larger samples increase the reliability of results; a single trial may reflect measurement error or chance.

Common lab tools: metric ruler for length, graduated cylinder for liquid volume, pan balance for mass, thermometer for temperature.

Models such as diagrams, physical replicas, and computer simulations represent objects or processes that are too large, small, slow, or dangerous to observe directly.

The cell is the basic unit of structure and function in living things; plant cells have a cell wall and chloroplasts, while animal cells do not.

Photosynthesis: carbon dioxide + water + light energy produces sugar (glucose) + oxygen, with chlorophyll in chloroplasts capturing the light.

In a food chain energy begins with the Sun, passes to producers, then to consumers; decomposers break down dead organisms and recycle nutrients to the soil.

Biotic factors are the living parts of an ecosystem (plants, animals, fungi); abiotic factors are the nonliving parts (water, sunlight, soil, temperature).

Adaptations are inherited body structures or behaviors, such as camouflage, thick fur, or migration, that improve survival in a particular habitat.

Inherited traits are passed from parents through genes; learned behaviors are acquired through experience or observation.

Complete metamorphosis has four stages (egg, larva, pupa, adult); incomplete metamorphosis has three (egg, nymph, adult).

Organisms are classified by shared characteristics, for example vertebrates (fish, amphibians, reptiles, birds, mammals) versus invertebrates.

Major human body systems include circulatory, respiratory, digestive, nervous, and skeletal-muscular, each with organs that work together for a specific job.

Matter is anything with mass and volume; solids have a fixed shape and volume, liquids have fixed volume but take the container's shape, gases fill their container.

A physical change (melting, dissolving, tearing) does not create a new substance; a chemical change (burning, rusting, baking) produces a new substance with different properties.

Mixtures can be separated by physical means such as filtering, sifting, or evaporating; the parts of a compound can be separated only by chemical means.

Mass is conserved during changes of state and during chemical reactions: total mass before equals total mass after.

Forces are pushes or pulls; balanced forces do not change motion, while unbalanced forces change an object's speed or direction.

Gravity pulls objects toward Earth's center and keeps planets in orbit; friction opposes motion between touching surfaces; magnetism can act at a distance.

Energy forms include kinetic (motion), potential (position or condition), light, sound, thermal, and electrical; energy transfers between forms but is not created or destroyed.

The six simple machines are lever, pulley, wheel and axle, inclined plane, wedge, and screw; they change the size or direction of a force but add no extra work.

Light reflects off surfaces and refracts when it passes between materials; sound travels as vibrations and needs a medium such as air, water, or a solid.

Earth's layers from outside in are crust, mantle, outer core (liquid), and inner core (solid); the crust and upper mantle are broken into slowly moving plates.

Moving plates cause earthquakes along faults, volcanoes near plate boundaries, and the building of mountains where plates collide.

Rock cycle: igneous rock forms when magma or lava cools, sedimentary rock forms from compacted and cemented sediments, and metamorphic rock forms under heat and pressure.

Weathering breaks rock apart in place, erosion carries the pieces away by water, wind, ice, or gravity, and deposition drops them in a new location.

Water cycle stages: evaporation and transpiration, condensation into clouds, precipitation, then runoff and collection in bodies of water.

Earth's rotation on its axis takes about 24 hours and causes day and night; revolution around the Sun takes about 365.25 days and, combined with Earth's 23.5-degree tilt, causes the seasons.

The Moon's gravity causes ocean tides, and the Moon's phases repeat about every 29.5 days as it orbits Earth.

Planets in order from the Sun: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.

Weather is the short-term condition of the atmosphere, while climate is the long-term average weather pattern of a region.