Physical Science
Exemplar Response: Maglev trains use electromagnets to achieve high-speed travel. To float, identical magnetic poles on the bottom of the train and on the track repel each other, pushing the heavy train up. To move forward, opposite magnetic poles pull the train from ahead, while matching magnetic poles push it from behind. Because the train floats, there is no rubbing friction with the track, allowing the train to slide smoothly and reach speeds over 300 miles per hour.
Life Science
Exemplar Response: Bioluminescence helps deep-sea creatures survive in the midnight zone. Hunters like the anglerfish use a glowing bait dangling in front of their mouth to entice prey. Other animals use bioluminescence for defense. For instance, deep-sea shrimp spit glowing blue slime when attacked, which blinds predators so the shrimp can escape. These specialized adaptations allow creatures to navigate, feed, and protect themselves without solar light.
Science Squad Field Journal Companion
EXEMPLARS 05 - 07
Page 3
Earth Science
Exemplar Response: Weathering and erosion are the processes that carve giant canyons over millions of years. Rivers carry rocks and gravel that act like sheets of sandpaper, scraping and wearing away the solid bedrock underneath. Rain also washes loose soil from canyon walls into the river, widening the chasm. Through continuous scraping and transport of sediments, flowing water is strong enough to slowly reshape the hardest stone on Earth.
Physical Science
Exemplar Response: Refraction is the bending and separation of light when it enters a new substance. White sunlight contains all colors combined. When sunlight enters a round raindrop, each color bends at a slightly different angle because of its wavelength; red light bends the least, and violet bends the most. The light then bounces off the back of the raindrop like a mirror and exits, separating into seven visible colored bands across the sky.
Life Science
Exemplar Response: Monarch butterflies use physical adaptations and smart behaviors to travel 3,000 miles. Because they weigh less than a paperclip, they conserve energy by riding rising currents of warm air, called thermals, to glide without flapping constantly. To navigate, they utilize an internal solar compass in their brains, looking at the Sun's position in the sky to ensure they always steer south toward the warmer forests of central Mexico.
Science Squad Field Journal Companion
EXEMPLARS 08 - 10
Page 4
Earth Science
Exemplar Response: Atmospheric rivers form when warm tropical sun evaporates water from the ocean into dense water vapor. Strong wind currents push this moisture-rich ribbon across the atmosphere. When this sky river hits cold mountain ranges on land, the vapor cools quickly and condenses. This turns the invisible steam back into liquid droplets, causing heavy rainstorms or severe winter blizzards that refill ground water reservoirs.
Physical Science
Exemplar Response: Potential energy is stored energy dependent on an object's height, whereas kinetic energy is the energy of actual motion. A roller coaster car relies on trading these two energy states. As the car climbs a hill, it accumulates potential energy. When it drops, gravity pulls it down and converts that potential energy into kinetic energy. At the bottom, kinetic energy is at its peak, providing the necessary speed to climb the next loop.
Life Science
Exemplar Response: When pests like caterpillars attack a plant, the plant releases chemicals called volatile organic compounds into the air. This scent acts like an SOS call that attracts predatory wasps, who fly to the plant and eat the caterpillars. Neighboring plants also detect this distress scent and start producing chemical defenses before caterpillars reach them, creating a shared community-wide defense system.
Science Squad Field Journal Companion
Detail how thermal energy from the Earth's core is transferred to the mantle. Explain how density differences drive the circular movement of convection currents.
Scientific Log (State your Claim, Evidence, and Reasoning)
Grade 7 Scientific Literacy Log • Systems Exploration
MS-PS1-3 • Chemical Reactions
Page 3
How humanity chemically re-engineers raw substances into high-performance polymers.
Everything in our modern world, from smart devices to heart stents, is built with synthetic materials. Unlike natural resources harvested straight from nature, synthetic substances are created through complex chemical reactions. By altering molecular alignments, chemists manipulate raw materials, like petroleum or plant oils, to form massive, long-chain molecules called polymers.
Synthetic plastics, nylon, and Kevlar are engineered specifically to possess properties not found in natural products. These materials are incredibly lightweight, waterproof, durable, and highly resistant to decay. While these characteristics make synthetic polymers exceptionally useful and cost-effective, they also generate major environmental challenges. Because they are designed to resist decay, synthetic materials do not naturally break down in landfills, creating a vital need for green chemistry solutions to design compostable polymers.
Analyze the societal benefits of engineering synthetic materials compared to using natural resources. Then, outline the long-term ecological consequences of their design.
Scientific Log (State your Claim, Evidence, and Reasoning)
Grade 7 Scientific Literacy Log • Systems Exploration
MS-LS1-2 • Cell Structure
Page 4
How microscopic organelles convert food into biochemical fuel.
Every breath you take and every muscle you flex is powered by tiny biological structures called mitochondria. These double-membrane organelles, found inside eukaryotic cells, are the sites where cellular respiration occurs.
Cellular respiration is a critical biochemical reaction that converts organic glucose from food into a usable energy molecule called ATP (adenosine triphosphate). Cells first break down glucose in the cytoplasm. Then, these fragments enter the mitochondria, where they react with oxygen. This reaction releases stored chemical bond energy, outputting carbon dioxide and water as waste products. Mitochondria act as microscopic power plants, ensuring the cell has continuous fuel to drive active transport, repair structural damage, and maintain homeostatic balances.
Describe the inputs and outputs of cellular respiration. Explain why organisms must breathe oxygen in order for mitochondria to keep cells alive.
Scientific Log (State your Claim, Evidence, and Reasoning)
Grade 7 Scientific Literacy Log • Systems Exploration
MS-ESS3-5 • Climate Change
Page 5
How planetary thermal energy balance is maintained by invisible atmospheric gases.
Without our atmosphere, Earth would be a frozen rock with an average surface temperature of -18 degrees Celsius. The comfort of our biosphere is sustained by the greenhouse effect, an essential global thermal system.
High-energy solar radiation crosses the transparent atmosphere, striking and warming Earth's surface. The ground then re-radiates this thermal energy as lower-frequency infrared light. Instead of escaping into outer space, this infrared light is absorbed by atmospheric greenhouse gases like carbon dioxide, methane, and water vapor. When these molecules absorb the energy, they vibrate and re-emit heat in all directions, trapping heat close to Earth. Today, human industrial activities have increased CO2 concentrations, trapping excess energy and causing global temperatures to steadily rise.
Explain the physics of the greenhouse effect. Explain how the atmosphere traps heat, and hypothesize the systemic changes that occur when greenhouse gas concentrations rise.
Scientific Log (State your Claim, Evidence, and Reasoning)
Grade 7 Scientific Literacy Log • Systems Exploration
MS-PS3-4 • Energy Transfer
Page 6
The molecular struggle of conduction, convection, and radiation.
Thermal energy is always on the move, seeking thermodynamic equilibrium by flowing from hot objects to cold objects. To stop this flow, scientists must block three distinct transfer mechanisms: conduction, convection, and radiation.
Conduction is the direct transfer of kinetic energy between colliding atoms, like heat traveling up a metal spoon. Convection is energy transfer within flowing fluids where hot, less dense pockets rise and cooler pockets sink. Radiation is energy transfer via electromagnetic infrared waves, requiring no physical matter to travel through. High-performance insulated vacuum flasks block all three: they use double-walled steel containers with a complete vacuum between them to block conduction and convection, and a shiny silver coating to reflect infrared radiation.
Differentiate between conduction, convection, and radiation. Explain how the mechanical features of a vacuum flask systematically prevent each type of heat transfer.
Scientific Log (State your Claim, Evidence, and Reasoning)
Grade 7 Scientific Literacy Log • Systems Exploration
MS-LS4-2 • Evolution
Page 7
The anatomical leftovers that reveal common ancestors in evolutionary history.
Living organisms possess physical structures designed precisely for survival. But sometimes, organisms contain anatomical structures with no apparent function at all. These are vestigial structures: biological remnants of an organism's evolutionary ancestry.
For instance, deep inside the bodies of modern baleen whales, you will find tiny hip and leg bones suspended in muscle. Whales do not have legs, nor do they walk, so why do these bones exist? They are evolutionary structural leftovers from ancient, four-legged land mammals that walked the Earth fifty million years ago before adapting to ocean environments. Similarly, cave-dwelling blind fish still develop non-functional, skin-covered eyes. These biological fossils prove that genes can linger long after lifestyles alter, serving as physical maps of an organism's lineage.
Explain what a vestigial structure is. Construct an argument showing how vestigial structures in modern species support the scientific theory of evolution and common ancestry.
Scientific Log (State your Claim, Evidence, and Reasoning)
Grade 7 Scientific Literacy Log • Systems Exploration
MS-ESS1-2 • Space Systems
Page 8
The invisible attraction structuring planets, stars, and massive galaxies.
Although we experience gravity as the force holding our feet to the floor, it is actually the principal architect of the cosmos. Gravitational force is an attractive force that exists between any two objects possessing mass. The strength of this attraction depends strictly on two key variables: the mass of the objects and the physical distance between them.
In space, gravity operates as a master orbital stabilizer. The Sun's enormous mass creates a deep gravitational well, trapping planets in stable circular and elliptical orbits. Because gravitational attraction drops off with distance, distant gas giants like Neptune orbit much more slowly than nearby rocky planets like Mercury. On a larger scale, gravity gathers billions of solar systems together into vast, spinning spiral galaxies, pulling matter inward to trigger stellar nursery births and form supermassive black holes at galactic centers.
Formulate an explanation detailing how mass and distance govern gravitational strength. Describe how these factors structure our planetary orbits and the shape of galaxies.
Scientific Log (State your Claim, Evidence, and Reasoning)
Grade 7 Scientific Literacy Log • Systems Exploration
MS-PS4-3 • Waves & Information
Page 9
The technological shift from vulnerable analog signals to reliable digital codes.
We live in an information age powered by wave transmission. To transmit voice, video, or data over long distances, engineers rely on physical waves using either analog signals or digital signals.
Analog signals represent information as continuous, undulating wave patterns that mimic real-world inputs, like a vinyl record groove mirroring sound pressure. However, as analog waves travel, they pick up environmental noise and structural interference, resulting in fuzzy static. In contrast, digital signals convert information into a series of discontinuous numerical pulses, usually binary code (zeros and ones). This numerical coding makes digital transmissions highly resistant to interference. Even if noise distorts a wave slightly, receiver computers can easily differentiate a clean "one" from a "zero," yielding highly clear audio, video, and data.
Compare analog and digital signals. Using wave interference as evidence, explain why digital signals are significantly more reliable for transmitting clear data over long distances.
Scientific Log (State your Claim, Evidence, and Reasoning)
Grade 7 Scientific Literacy Log • Systems Exploration
MS-ESS3-3 • Earth Resources & Human Impact
Page 10
The geologic and social consequences of overdrawing groundwater reserves.
Much of the fresh water sustaining global agriculture isn't stored in lakes or rivers, but in subterranean geologic formations called aquifers. An aquifer consists of layers of porous sand, gravel, or fractured bedrock that act as a sponge, holding vast reservoirs of groundwater accumulated over thousands of years.
When rainwater filters down through the soil, it gradually recharges aquifers. However, modern heavy machinery pumps water out of deep wells at rates significantly faster than natural cycles can replenish them. This severe overdraft triggers serious environmental issues. Beyond depleting agricultural water supplies, empty spaces within the geologic sediment can collapse under the weight of the land above. This physical collapse causes land subsidence—where the ground surface literally sinks—damaging roads, cracking building foundations, and permanently reducing the aquifer's storage capacity.
Explain the structure of a geological aquifer. Analyze the physical and ecological consequences that occur when groundwater extraction rates exceed recharge rates.
Scientific Log (State your Claim, Evidence, and Reasoning)
Grade 7 Scientific Literacy Log • Systems Exploration
MS-PS1-3
Exemplar CER Response: Claim: Synthetic polymers offer massive structural and medical advantages over natural resources, but their durability generates a long-term waste feedback loop. Evidence: Synthetic materials are created through chemical reactions that build strong, long-chain molecules (polymers). These properties yield cheap, lightweight, waterproof devices, but they do not naturally decay in landfills. Reasoning: Because the chemical bonds of synthetic polymers are engineered to be highly stable and resistant to environmental decomposers, they accumulate permanently, necessitating a shift toward biodegradable material designs.
MS-LS1-2
Exemplar CER Response: Claim: Eukaryotic cells rely on the chemical reactions of cellular respiration inside the mitochondria to generate biochemical fuel (ATP) to maintain homeostasis. Evidence: Inside the mitochondria, organic glucose from digested food reacts with oxygen to release stored chemical bond energy, outputting carbon dioxide, water, and ATP. Reasoning: Organisms breathe in oxygen because it acts as a critical reactant to break down glucose bonds. Without oxygen, cellular respiration stalls, halting ATP production, which causes cellular activities like active transport and structure repair to fail.
Middle School Science Series Companion
EXEMPLARS 05 - 07 (MS-ESS & MS-PS)
Page 3
MS-ESS3-5
Exemplar CER Response: Claim: The greenhouse effect is a vital thermal trap regulated by atmospheric gases, but rising concentrations of these gases overheat the planet. Evidence: High-energy solar radiation warms the ground, which then emits lower-frequency infrared heat. Greenhouse gases like carbon dioxide and methane absorb this infrared light, causing them to vibrate and re-radiate heat back to the surface. Reasoning: As humans emit excess CO2, more infrared heat waves are intercepted instead of escaping into space. This systematically traps excess energy within our atmosphere, leading to rising global temperatures.
MS-PS3-4
Exemplar CER Response: Claim: Insulated vacuum flasks successfully preserve internal temperatures by systematically blocking conduction, convection, and radiation. Evidence: Conduction transfers heat via direct atomic collisions, convection moves heat through fluid circulation, and radiation uses infrared electromagnetic waves. Flasks feature double-walled steel with a true vacuum in between and a shiny silvered inner wall. Reasoning: Because a vacuum contains no physical matter, atomic collisions (conduction) and fluid movement (convection) cannot occur across the barrier. Additionally, the shiny silver coating reflects radiating infrared waves, preserving temperature.
MS-LS4-2
Exemplar CER Response: Claim: Vestigial structures serve as physical evidence of evolutionary history, indicating that modern species descended and diverged from common ancestors. Evidence: Whales possess tiny leg and hip bones suspended in muscle that serve no swimming function. Blind cave fish still develop skin-covered eyes that cannot see light. Reasoning: These biological remnants only exist because the ancestors of these organisms had functional versions of these organs (four-legged land mammals for whales, sighted surface fish for cave fish). As environments altered, selective pressures changed, but structural genes lingered.
Middle School Science Series Companion
EXEMPLARS 08 - 10 (MS-ESS & MS-PS)
Page 4
MS-ESS1-3
Exemplar CER Response: Claim: Gravitational forces hold astronomical objects in stable orbits, structuring our solar system and entire galaxies according to mass and distance. Evidence: Gravity is an attractive force between objects with mass. The Sun's enormous mass traps planets in stable orbits. Since gravity weakens with distance, closer planets like Mercury travel faster than distant giants like Neptune. Reasoning: Because gravity operates as an attractive field, the orbital velocities must balance the pulling force. If planets traveled too slowly or if the Sun's mass dropped, gravity would pull objects inward or allow them to escape.
MS-PS4-3
Exemplar CER Response: Claim: Digital signals are fundamentally more reliable for long-distance data transmission than analog signals due to their resistance to wave interference. Evidence: Analog signals are continuous, repeating waves representing real inputs, which collect environmental noise and static during transport. Digital signals translate wave pulses into numerical codes (binary 0s and 1s). Reasoning: When waves experience interference, analog waveforms permanently warp and decay. However, because digital waves transmit numerical codes, receiver computers only have to identify if a pulse is high (1) or low (0), filtering out any accumulated noise.
MS-ESS3-3
Exemplar CER Response: Claim: Extracting groundwater from aquifers faster than natural recharge rates permanently reduces geologic water storage capacity and triggers ground collapse. Evidence: Aquifers are porous underground layers of sand, gravel, and rock that trap water. Pumping water out faster than rainwater filters down causes the empty sediment spaces to collapse, triggering land subsidence that cracks buildings. Reasoning: When water is removed, the physical buoyant support holding up the sediment grains vanishes. The pressure of the heavy soil above squeezes the pores closed permanently, meaning the aquifer can never hold groundwater again even if it rains.
Middle School Science Series Companion
