Introduction to STEM and Chemistry Concepts

Unit 1: Introduction to STEM + Science Skills

• Scientific Method: A systematic approach to experimentation, including:
  • Question: The problem to be investigated.
  • Hypothesis: A testable prediction (If...Then...Because...).
  • Research: Gathering background information.
  • Experiment: Testing the hypothesis.
  • Conclusion: Interpreting the results.
• Independent Variable (IV): The factor changed in an experiment.
• Dependent Variable (DV): The factor measured as a result of the experiment.
• Control Variables (CV): Factors kept constant during the experiment.
• Qualitative Observation: Descriptive observation.
• Quantitative Observation: Measurement-based observation.
• Inference: A conclusion drawn from observation.

Unit 3: Chemistry | The Nature of Matter

• Chemical Properties: Describe how a substance reacts with other materials (e.g., reactivity with water, flammability, corrosiveness).
• Physical Properties: Describe the substance itself (e.g., hardness, malleability, ductility, melting/boiling points, solubility, viscosity, conductivity, clarity).
• Physical Change: A change in appearance or state without forming a new substance; reversible.
• Chemical Change: A change where a new substance is formed; not easily reversed.
• Atom Structure:
  • Shells: Regions surrounding the nucleus containing electrons.
  • Valence Electrons: Electrons in the outermost shell.
  • Octet Rule: Atoms tend to gain, lose, or share electrons to achieve a full outermost electron shell (2-8-8-2).
• Periodic Table Organization: Organized by the number of protons and electrons in a neutral atom.

Unit 2: Biology | Sustainable Ecosystems & Climate Change

• Ecosystem: A community of living organisms (biotic) interacting with their nonliving environment (abiotic).
• Sustainability: The ability of an ecosystem to maintain itself without collapsing.
• Dynamic Equilibrium: A state of balance in an ecosystem where all components have a role.
• Biodiversity: Variety of life (biotic and abiotic factors) in an ecosystem.
• Earth's Systems:
  • Atmosphere: Gases surrounding the Earth.
  • Lithosphere: Solid Earth's crust and upper mantle.
  • Hydrosphere: All water on Earth.
  • Biosphere: All living organisms and their environment.
• Photosynthesis & Cellular Respiration:
  • Photosynthesis: Plants use water, carbon dioxide, and sunlight to produce glucose (food) and oxygen.
  • Cellular Respiration: Living things use glucose and oxygen to release energy and produce carbon dioxide and water. Plants and animals do both.
• Nutrient Cycles: Nitrogen and Phosphorus are essential for life processes.
• Greenhouse Effect: Greenhouse gases trap heat in the atmosphere, warming the planet.
• Food Chains & Webs:
  • Food Chain: A linear sequence of organisms where each feeds on the previous one.
  • Food Web: A complex network of interconnected food chains. Food webs enhance sustainability.
• Trophic Levels: Feeding positions in a food chain or web.
  • Producers (plants)
  • Consumers (herbivores, carnivores, omnivores)
  • Decomposers
• Energy Transfer: Only ~10% of energy is transferred between trophic levels.
• Threats to Ecosystems:
  • Overexploitation: Overuse of resources.
  • Invasive Species: Introduction of non-native species.
• Sustainability Principles: Focuses on preserving ecosystems for future generations (e.g., the 7 generations principle).

Unit 4: Physics | Principles & Applications of Electricity

• Static Electricity: Stationary electric charge.
• Current Electricity: Flow of electric charge.
• Charging Methods:
  • Friction: Transfer of electrons by rubbing.
  • Contact: Direct transfer of electrons.
  • Induction: Temporary charge separation without direct contact.
• Electroscope: Device for detecting electric charges (e.g., positive or negative).
• Conductors & Insulators:
  • Conductors: Materials that allow electric current to flow easily.
  • Insulators: Materials that do not allow electric current to flow easily.
• Electric Current (I): The rate of flow of electric charge (measured in amperes).
• Voltage (V): The potential difference (measured in volts).
• Resistance (R): Opposition to the flow of electric current (measured in ohms).
• Ohm's Law: The relationship between voltage, current, and resistance (V = IR).
• Factors Affecting Resistance: Length, width, material, and temperature.

Explore essential concepts from Unit 1 and Unit 3 covering the scientific method and the nature of matter. This quiz tests your understanding of variables, observations, and the properties of substances in chemistry. Assess your knowledge and application of these fundamental scientific principles.