Which observation would support the idea that Earth is round?

Which observation would support the idea that Earth is round?

• A. The Earth is flat.
• B. The Earth is spherical.
• C. The Sun orbits the Earth.
• D. The Moon's phases change.

Answer: (B)

Think about what “round” means in this context—it refers to Earth having a curved, globe-like shape. A statement that the Earth is spherical directly asserts that shape, so it best supports the idea that Earth is round. This aligns with observations that imply curvature and a ball-like form, such as how ships disappear hull-first over the horizon and how lunar eclipses show a round shadow cast by Earth. In contrast, saying the Earth is flat would contradict roundness, claiming a flat surface; saying the Sun orbits the Earth describes a motion model rather than Earth’s shape; and the Moon’s phases pertain to the Moon’s orbit and sunlight, not to the Earth's own shape.

Think about what “round” means in this context—it refers to Earth having a curved, globe-like shape. A statement that the Earth is spherical directly asserts that shape, so it best supports the idea that Earth is round. This aligns with observations that imply curvature and a ball-like form, such as how ships disappear hull-first over the horizon and how lunar eclipses show a round shadow cast by Earth. In contrast, saying the Earth is flat would contradict roundness, claiming a flat surface; saying the Sun orbits the Earth describes a motion model rather than Earth’s shape; and the Moon’s phases pertain to the Moon’s orbit and sunlight, not to the Earth's own shape.