Free GED Science Earth and Space Science Practice Test Flashcards
35 cards from real GED practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 20 Free GED Science Earth and Space Science Practice Test flashcards as text
Which layer of the Earth is the thinnest?
Answer: Crust
Earth's crust is the outermost and thinnest layer — ranging from about 5 km under oceans to 35-70 km under continents.
What is the primary gas in Earth's atmosphere?
Answer: Nitrogen
Earth's atmosphere is approximately 78% nitrogen, 21% oxygen, and smaller amounts of other gases.
Which type of rock forms when molten rock cools and solidifies?
Answer: Igneous
Igneous rock forms from the cooling and solidification of magma (underground) or lava (on the surface).
What causes the seasons on Earth?
Answer: The tilt of Earth's axis as it orbits the Sun
Earth's seasons are caused by the 23.5° tilt of its axis. As Earth orbits the Sun, different hemispheres receive more direct sunlight at different times.
What is the name of the supercontinent that existed approximately 300 million years ago?
Answer: Pangaea
Pangaea was the single supercontinent that existed about 300-200 million years ago before breaking apart into today's continents.
Which of the following is the correct order of the planets from closest to farthest from the Sun?
Answer: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
The correct order (using the mnemonic 'My Very Educated Mother Just Served Us Nachos') is Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.
What is the water cycle process where liquid water becomes water vapor?
Answer: Evaporation
Evaporation is the process by which liquid water (from oceans, lakes, etc.) is converted to water vapor through solar energy.
A seismograph measures:
Answer: Earthquake intensity and seismic waves
A seismograph is an instrument used to detect and measure seismic waves caused by earthquakes or other ground movements.
Which layer of the Sun produces the light and heat we receive on Earth?
Answer: The photosphere
The photosphere is the visible surface of the Sun from which light and heat are emitted into space.
What is the primary cause of ocean tides on Earth?
Answer: The Moon's gravitational pull
Ocean tides are caused primarily by the Moon's gravitational pull, which creates bulges of water on the near and far sides of Earth.
Which of the following is an example of a renewable resource?
Answer: Solar energy
Solar energy is renewable because the Sun continuously produces energy. Coal, natural gas, and petroleum are fossil fuels — non-renewable resources formed over millions of years.
What type of boundary exists where two tectonic plates move away from each other?
Answer: Divergent boundary
At a divergent boundary, two tectonic plates move apart, allowing magma to rise and create new crust — as seen at the Mid-Atlantic Ridge.
What is the term for the point on Earth's surface directly above an earthquake's origin?
Answer: The epicenter
The epicenter is the point on Earth's surface directly above the focus (hypocenter), where the earthquake originates underground.
Which planet is known as the 'Red Planet'?
Answer: Mars
Mars is called the Red Planet because its surface is covered with iron oxide (rust), giving it a reddish appearance.
In the rock cycle, which process converts igneous rock into sedimentary rock?
Answer: Weathering, erosion, and deposition
Igneous rocks are broken down by weathering and erosion into sediments. These sediments are deposited and compacted over time to form sedimentary rock.
What is the greenhouse effect?
Answer: The warming of Earth's surface due to atmospheric gases trapping heat
The greenhouse effect occurs when greenhouse gases (CO₂, methane, water vapor) in the atmosphere absorb and re-emit infrared radiation, trapping heat near Earth's surface.
What is a light-year?
Answer: The distance light travels in one year
A light-year is a unit of distance equal to about 9.46 × 10¹² kilometers — the distance light travels in one year at 300,000 km/s.
What causes a solar eclipse?
Answer: The Moon passes between Earth and the Sun
A solar eclipse occurs when the Moon passes directly between Earth and the Sun, blocking the Sun's light from reaching parts of Earth.
Fossils are most commonly found in which type of rock?
Answer: Sedimentary rock
Fossils form in sedimentary rock. Organisms are buried in sediment which gradually hardens into rock, preserving the organism's remains or imprints.
Which of the following BEST describes the Milky Way?
Answer: A spiral galaxy containing our solar system
The Milky Way is a barred spiral galaxy containing billions of stars, including our Sun, along with our entire solar system.