Chemical Reactions
Geoscience
Ecosystems
Waves
Natural Selection
100
How many atoms of each element are in the following molecule?
2 NaC2H3O2
Na: 2
C: 4
H: 6
O: 4
100
What are tectonic plates?
Large pieces of Earth's crust that float on the mantle and move atop magma beneath the surface.
100
What is an ecosystem?
A community of living organisms plus their physical environment interacting as a system.
100
What is a wave? Give one example of a wave you can hear or see
A wave is a repeating disturbance that transfers energy through matter or space.
100
What is natural selection? Give one simple example of a trait that might help an animal survive.
Definition: Natural selection is the process where individuals with traits better suited to an environment are more likely to survive and reproduce, passing those traits to offspring.
Example traits: camouflage coloring, thick fur in cold climates, long beaks for getting food.
200
Give one observable sign that a chemical reaction has occurred.
Color change, Gas produced, Temperature change, solid formed, etc
200
Name the type of plate boundary where two plates move away from each other
Divergent Plate Boundary
200
Define producer and give one example from a typical terrestrial ecosystem.
an organism that makes its own food by photosynthesis. Example: grass or tree.
200
Name and briefly describe two properties of waves
Wavelength: distance between two corresponding points on consecutive waves (e.g., crest to crest).
Frequency: number of wave cycles that pass a point each second (higher frequency = more cycles/sec).
Amplitude: height of the wave from the middle to a crest (related to energy or loudness/brightness).
200
Explain in one sentence how genetic variation in a population can come from sexual reproduction.
Sexual reproduction mixes genes from two parents, producing offspring with combinations of traits that differ from each parent, increasing genetic variation.
300
This law explains why mass is conserved in a chemical reaction.
Law of conservation of mass
300
Who first theorized plate tectonics?
Alfred Wegener
300
What is biodiversity, and why is it important for ecosystem stability? (one–two sentences)
Biodiversity is the variety of life. Higher biodiversity usually increases resilience to change and disturbances.
300
How does the amplitude of a sound wave relate to what we hear? Explain in one sentence.
Higher amplitude sound waves are heard as louder sounds; lower amplitude waves are quieter. (Relates amplitude to energy and loudness.)
300
A population of beetles has green and brown individuals. Birds eat more green beetles because they are easier to see on the brown soil. Over several generations, more brown beetles appear. Explain why this change happens using natural selection.
Brown beetles are less likely to be eaten, so they survive and reproduce more; their genes become more common, increasing the proportion of brown beetles over generations.
400
Describe the difference between a chemical and a physical change
Chemical changes result in the physical properties of the substance changing, while a physical change keeps the physical properties
400
Sedimentary rock transforms into metamorphic rock by
Intense Heat and Pressure
400
Explain how energy flows through an ecosystem (name the direction: from ___ to ___ and give an example chain with three levels).
Energy flows from producers to consumers to decomposers.
Example: grass → rabbit → fox.
400
Describe, using scientific vocabulary, why sound can be heard on the other side of a wall and is significantly quieter than in the room of origin.
The sound waves are transmitted through various mediums (air, wall, air again). Wave energy is partially absorbed through the wall, which causes the wave amplitude to decrease, thus affecting the volume.
400
Name one piece of evidence that shows species have changed over long periods of time, and give a short sentence explaining how that evidence shows change.
Example evidence: fossils showing different organisms in older rock layers than in newer layers.
Explanation: Because older rocks have different fossils than newer rocks, the kinds of organisms on Earth have changed over time.
500
A student mixes two liquids in a closed container. Before mixing, the total mass is 80.0 g. After the reaction finishes, the student measures the mass and records 78.0 g. The student says mass was lost in the reaction. Explain why the student's conclusion is probably wrong and give one simple, realistic reason why the measured mass might be lower (even though mass is actually conserved).
Likely experimental reason for lower measured mass: The container might not have been fully closed and some gas escaped, or some liquid splashed out during mixing. Other simple reasons include evaporation or weighing errors.
500
The gradual breakdown of rocks into smaller pieces is called
Weathering
500
Describe one way human activity can reduce biodiversity and one action that can help protect it.
Habitat destruction reduces biodiversity. Action: Protect or restore habitats; establish conservation areas.
500
A student measures a sound wave in air and finds the frequency is 512 Hz. Using the approximate speed of sound in air 343 m/s, calculate the wavelength of this sound.
Wavelength = Speed / Frequency
Speed = Frequency * Wavelength
Wavelength = Speed / Frequency
Wavelength =(343 m/s) / (512 Hz) = 0.67 m
500
Describe how the advantages and disadvantages of sexual and asexual reproduction
Sexual: Offers genetic variation, but requires two parents and is slower
Asexua: Much faster, less biodiversity, only requires one parent