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84 lessons · 3rd Grade
The scientific method is a systematic approach to investigating questions. It involves making observations, forming hypotheses, conducting experiments, analyzing data, and drawing conclusions.
Variables in experiments include the independent variable (what you change), dependent variable (what you measure), and controlled variables (what you keep the same).
A hypothesis is a testable prediction about what will happen in an experiment. A good hypothesis is specific and based on prior knowledge or observations.
Models help scientists represent complex systems. Physical models (like a globe), mathematical models (like equations), and computer models all simplify reality to make it easier to study.
Engineers use the design process to solve problems: identify the problem, research, brainstorm solutions, build a prototype, test it, evaluate results, and improve the design.
Light travels in straight lines and can be reflected, refracted, or absorbed. Mirrors reflect light, lenses refract (bend) light, and dark surfaces absorb light.
Waves transfer energy without transferring matter. Transverse waves (like light) vibrate perpendicular to the direction of travel. Longitudinal waves (like sound) vibrate parallel.
The electromagnetic spectrum includes radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays, ordered by increasing frequency and energy.
Conservation efforts protect natural resources and biodiversity. Reducing waste, recycling, protecting habitats, and using renewable energy all help preserve Earth's resources.
Data analysis involves organizing, displaying, and interpreting information to find patterns. Scientists use tables, graphs, and statistics to make sense of experimental results.
Scientific arguments require a claim, evidence, and reasoning. The claim states what you believe, evidence provides data supporting it, and reasoning explains how the evidence supports the claim.
Renewable resources like solar panels and wind turbines generate clean energy. Human innovation in engineering continues to make these technologies more efficient and affordable.
Light behaves as both a wave and a particle. White light can be separated into a spectrum of colors using a prism. Each color has a different wavelength.
Sound is a vibration that travels through matter as a wave. It cannot travel through a vacuum. Sound travels fastest through solids and slowest through gases.
Sound waves have properties including amplitude (loudness), frequency (pitch), and wavelength. Higher frequency means higher pitch. Greater amplitude means louder sound.
Engineers must consider constraints (limitations like cost, time, and materials) and criteria (requirements the solution must meet) when designing solutions to problems.
Peer review is how scientists check each other's work. Before research is published, other experts evaluate the methods, data, and conclusions to ensure they are valid.
Technology is the application of scientific knowledge to solve practical problems. From simple tools to complex computers, technology shapes how humans interact with the world.
Climate data from ice cores, tree rings, and ocean sediments helps scientists understand past climate patterns and predict future changes.
Biodiversity—the variety of life in an ecosystem—makes ecosystems more resilient. Loss of biodiversity from human activities threatens ecosystem stability worldwide.