8th grade science STAAR

Speed & Acceleration (6.8C, 7.7A)

  • Speed Formula: Speed = Distance / Time

  • Acceleration Formula: Acceleration = (Final Speed - Initial Speed) / Time

  • Graphing Motion: Distance-time graphs show speed; steeper slope indicates faster speed.

    • Curved line signifies changing speed.

Review Questions:

  1. What happens to an object when forces are balanced?

  2. What is the formula for acceleration?

  3. How does Newton's Third Law apply to a rocket launch?

  4. Give a real-world example of an unbalanced force affecting motion.

Energy & Energy Transformations (3. Energy & Energy Transformations; 6.8A, 6.8A)

  • Potential Energy: Stored energy (gravitational, elastic, chemical, nuclear)

  • Kinetic Energy: Energy of motion, dependent on mass and velocity

  • Energy Transformations Example: Flashlight: Chemical (battery) → Electrical → Light

  • Law of Conservation of Energy: Energy is neither created nor destroyed, only transformed.

Review Questions:

  1. What is an example of kinetic energy?

  2. How does energy transform in a flashlight?

  3. What does the Law of Conservation of Energy state?

  4. How does energy transfer occur in a roller coaster ride?

Earth & Space (4. Earth & Space)

  • Seasons: Caused by Earth's tilt and revolution around the Sun; opposite seasons in the Northern & Southern Hemispheres.

Metals, Nonmetals, and Metalloids (6.6A, 6.6C)

  • Metals: Shiny (luster), good conductors of heat and electricity, malleable, ductile, high density.

  • Rare Earth Elements: Found in specific areas, utilized in technology such as electronics and magnets.

  • Nonmetals: Dull, poor conductors, brittle, low melting and boiling points.

  • Metalloids: Exhibit properties of both metals and nonmetals; classified as semiconductors.

Review Questions:

  1. How do metalloids differ from metals and nonmetals?

  2. What are three physical properties of metals?

  3. Why are rare Earth elements important in technology?

  4. What are two examples of how metals are used in everyday life?

Force & Motion (2. Force & Motion; Newton's Laws of Motion 8.6C, 8.7B)

  • 1st Law (Inertia): Objects in motion stay in motion unless acted upon by an unbalanced force; objects at rest stay at rest.

  • 2nd Law: Force = Mass x Acceleration (F = ma); greater mass requires more force to accelerate.

  • 3rd Law: Every action has an equal and opposite reaction; explains phenomena such as rocket launches and jumping.

  • Unbalanced Forces: Cause acceleration, changes in speed or direction, and deformations.

  • Balanced Forces: Result in no movement and constant velocity.

Review Questions:

  1. How do spring tides differ from neap tides?

  2. What causes the Seasons on Earth?

  3. Why does the Moon affect tides more than the Sun?

  4. How does the tilt of the Earth affect daylight hours throughout the year?

Weather & Climate (5. Weather & Climate)

  • Convection Currents: Sun heats air → warm air rises; cool air sinks, forming wind and ocean currents.

  • Global Winds & Weather Maps: High pressure equals clear skies; low pressure triggers storms.

  • Oceans & Weather: Warm ocean water fuels hurricanes; El Niño and La Niña affect global climate patterns.

Review Questions:

  1. What causes convection currents in the atmosphere?

  2. How do high and low pressure systems affect the weather?

  3. Why do hurricanes form over warm ocean water?

  4. How do ocean currents influence climate in coastal regions?

Organisms & Ecosystems (6. Organisms & Ecosystems; 8.11A, 8.11C)

  • Biodiversity = Sustainability: More biodiversity leads to a more stable ecosystem.

  • Ecological Succession:

    • Primary: No soil (e.g., from volcanoes, glaciers); takes longer to develop ecosystems.

    • Secondary: Soil remains (e.g., after fires, floods); recovers faster.

  • Human Impact on Oceans & Watersheds:

    • Negative: Pollution, overfishing, habitat destruction.

    • Positive: Artificial reefs, conservation efforts, protected marine areas.

Review Questions:

  1. How does biodiversity affect the sustainability of an ecosystem?

  2. What is the difference between primary and secondary succession?

  3. What are two human activities that negatively impact ocean ecosystems?

  4. How can humans help restore damaged ecosystems?

Cells, Genetics, & Human Body Systems (7. Cells, Genetics, & Human Body Systems; 7.12D, 7.12F, 8.13A, 6.13A)

  • Cell Theory:

    • All living things are made of cells.

    • Cells are the basic unit of life.

    • All cells come from preexisting cells.

  • Organelles & Functions:

    • Nucleus: Control center (DNA).

    • Mitochondria: Powerhouse (energy production).

    • Chloroplasts: Conduct photosynthesis in plant cells.

    • Vacuole: Storage.

Review Questions:

  1. What are the three main parts of the Cell Theory?

  2. Which organelle is known as the powerhouse of the cell?

  3. What is the function of chloroplasts?

  4. How does the cell membrane help maintain homeostasis?