True/False
The Sun is located at the center of our Solar System.
True
What keeps the planets in orbit around the Sun?
A) Magnetism
B) Gravity
C) Nuclear fusion
D) Friction
B) Gravity
Rotation
A) The path Earth follows around the Sun, taking about 365 days
B) Earth spinning on its axis, taking about 24 hours
C) The small shadow during an eclipse
D) The day when day and night are equal length
B) Earth spinning on its axis, taking about 24 hours
Explain how Earth’s rotation and revolution together cause day/night and the seasons.
Earth’s rotation is the spin on its axis every ~24 hours and causes day and night as different sides face the Sun. Earth’s revolution is its orbit around the Sun every ~365.25 days; because Earth is tilted about 23.5°, different hemispheres receive more direct sunlight at different times of year, producing seasons and changing day length.
Gravity is a force that only pulls objects downward on Earth.
False — Gravity is a universal attractive force between all objects with mass.
Which layer of the Sun is responsible for nuclear fusion?
A) Chromosphere
B) Corona
C) Core
D) Photosphere
C) Core
Revolution
A) Earth's movement around the Sun, taking about 365.25 days
B) The process of hydrogen fusing into helium
C) The bright outer layer of the Sun
D) A small rocky object orbiting the Sun
A) Earth's movement around the Sun, taking about 365.25 days
Describe nuclear fusion in a star and why it produces so much energy.
Nuclear fusion in a star’s core fuses hydrogen nuclei into helium under extreme heat and pressure. A tiny amount of mass is converted into a large amount of energy (E = mc²), which is released as light and heat that can warm and power planets.
Nuclear fusion in stars converts hydrogen into helium, releasing enormous energy.
True
Which of the following is classified as a gas giant?
A) Mercury
B) Mars
C) Earth
D) Saturn
D) Saturn
Umbra
A) The outer atmosphere of the Sun that is visible during an eclipse
B) The partial shadow during an eclipse
C) The total, darkest part of a shadow during an eclipse
D) The shape of the Moon during a quarter phase
C) The total, darkest part of a shadow during an eclipse
Define gravity and explain why inner planets orbit faster than outer planets.
Gravity is the attractive force between objects with mass; its strength increases with mass and decreases with distance. Inner planets feel a stronger pull from the Sun because they are closer, so they must move faster to balance that pull and stay in orbit, while outer planets feel less pull and orbit more slowly.
The Moon produces its own light, which is why we can see it at night.
False — The Moon reflects sunlight; it does not generate its own light.
What causes the day/night cycle on Earth?
A) Earth's revolution around the Sun
B) The Sun moving around Earth
C) Earth's rotation on its own axis
D) The Moon blocking sunlight
C) Earth's rotation on its own axis
Habitable Zone
A) The area around a star where liquid water can exist on a planet's surface
B) The region where planets have rings
C) The distance at which a planet has zero gravity
D) The inner core of a star where fusion happens
A) The area around a star where liquid water can exist on a planet's surface
Explain why eclipses don’t happen every month even though the Moon orbits Earth monthly.
Answer: The Moon’s orbit is tilted about 5° relative to Earth’s orbit, so the Sun, Earth, and Moon usually are not perfectly aligned at new or full moon. Eclipses only occur when a new or full moon happens near the orbit’s nodes, where the two orbital planes cross.
Earth's seasons are caused by its changing distance from the Sun.
False — Seasons are caused by Earth's 23.5° axial tilt, not its distance.
Which factor most directly explains why seasons occur on Earth?
A) Earth's changing distance from the Sun during its orbit
B) The tilt of Earth's axis relative to its orbit around the Sun
C) Variations in the Sun’s energy output throughout the year
D) The Moon’s gravitational pull on Earth
B) The tilt of Earth's axis relative to its orbit around the Sun
Waxing vs. Waning (choose the correct pair)
A) Waxing = lit area shrinking; Waning = lit area growing
B) Waxing = lit area growing; Waning = lit area shrinking
C) Waxing = new moon only; Waning = full moon only
D) Waxing = Moon getting farther; Waning = Moon getting closer
B) Waxing = lit area growing; Waning = lit area shrinking
A planet is in the habitable zone but has no atmosphere and spins once every 4 hours. Is it a good candidate for life? Explain with three reasons.
No — without an atmosphere there is no temperature regulation or protection from radiation, so liquid water can’t stay stable. Rapid rotation could cause extreme winds and unstable surface conditions. Also, no atmosphere means no gases needed for life’s chemistry, so being in the habitable zone alone is not enough.