Question

give four ways to demonstrate that earth is spherical.
ships sailing away on the ocean disappear starting at the bottom and moving to the top.
the shadow cast by the earth on the moon is round.
objects roll downhill.
the sun is at different altitudes in the sky for different longitudes.
the shape of the sun in the sky is circular.
photographs taken by orbiting satellites show that earth is round.
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Explanation:

• Ships sailing away: As Earth is spherical, the hull disappears first (curvature).
• Lunar eclipse shadow: Earth’s shadow on Moon is round, implying a spherical shape.
• Satellite photos: Direct visual proof of Earth’s roundness.
• Sun’s altitude (for different longitudes, though latitude is more accurate, but the option is given; the variation in Sun’s position with location supports a spherical Earth).

Objects rolling downhill relates to gravity/slope, not Earth’s shape. Sun’s circular shape doesn’t relate to Earth’s shape.

Answer:

• Ships sailing away on the ocean disappear starting at the bottom and moving to the top.
• The shadow cast by the Earth on the Moon is round.
• The Sun is at different altitudes in the sky for different longitudes.
• Photographs taken by orbiting satellites show that Earth is round.