General Science: Earth and Space Flashcards
6 cards from real AFCT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 General Science: Earth and Space flashcards as text
What causes the seasons on Earth?
Answer: The tilt of Earth's axis at 23.5 degrees relative to its orbital plane
Earth's seasons result from the 23.5-degree tilt of its rotational axis. As Earth orbits the Sun, different hemispheres receive more direct sunlight at different times of year, creating seasons.
What type of rock is formed from cooled and solidified magma or lava?
Answer: Igneous rock
Igneous rocks form when molten rock (magma underground or lava at the surface) cools and crystallizes. Examples include granite (intrusive/slow cooling) and basalt (extrusive/fast cooling).
What is the main composition of the Sun?
Answer: Hydrogen and helium
The Sun is composed of approximately 73% hydrogen and 25% helium by mass, with the remaining 2% being heavier elements. Nuclear fusion in the core converts hydrogen into helium, producing the Sun's energy.
What layer of Earth's atmosphere contains the ozone layer that protects life from harmful UV radiation?
Answer: Stratosphere
The ozone layer is found in the stratosphere, roughly 15-35 km above Earth's surface. Ozone (O3) molecules absorb most of the Sun's harmful ultraviolet-B and ultraviolet-C radiation.
What drives the movement of tectonic plates on Earth?
Answer: Convection currents in the mantle
Tectonic plates are driven primarily by convection currents in Earth's mantle. Heat from the core causes mantle rock to slowly circulate, with hotter material rising and cooler material sinking, dragging plates along.
What is a light-year a measure of?
Answer: Distance
A light-year is a unit of distance, not time. It is the distance that light travels in one year in a vacuum, approximately 9.46 trillion kilometers (5.88 trillion miles).