Science Flashcards

A student observes that a dropped ball accelerates downward and then hits the ground. Which force is primarily responsible for this acceleration?

Answer: Gravity

Gravity is the attractive force between Earth and the ball that causes it to accelerate downward at approximately 9.8 m/s².

During photosynthesis, plants convert light energy into chemical energy stored in which molecule?

Answer: Glucose

Plants use light energy to convert carbon dioxide and water into glucose (C₆H₁₂O₆), storing energy in its chemical bonds.

Which of the following best describes a physical change?

Answer: Ice melting into liquid water

Melting ice is a physical change because only the state of matter changes; the chemical composition of water (H₂O) remains the same.

The rock cycle describes how rocks change over time. Which process transforms igneous rock into sedimentary rock?

Answer: Weathering, erosion, and compaction

Igneous rock is broken down by weathering and erosion into sediments, which are then compacted and cemented to form sedimentary rock.

A food web shows the feeding relationships in an ecosystem. What happens to the population of rabbits if all the foxes are removed from the ecosystem?

Answer: Rabbit population initially increases due to less predation

Without fox predation, the rabbit population would initially increase rapidly, though this could later cause resource depletion and population crash.

Which layer of Earth's structure is responsible for generating Earth's magnetic field?

Answer: Outer core

Earth's magnetic field is generated by the movement of molten iron and nickel in the liquid outer core, creating electric currents.

A student tests the effect of sunlight on plant growth by growing two identical plants, one in sunlight and one in the dark. What is the independent variable in this experiment?

Answer: Presence or absence of sunlight

The independent variable is what the experimenter deliberately changes — in this case, the presence or absence of sunlight.