Earth Science Reading Lesson · Grades 3–5

The Vast Ocean

A reading comprehension lesson about Earth’s oceans — covering the four major oceans, how much of Earth they cover, ocean zones from surface to deep, and the amazing creatures that live there. Includes printable worksheet with questions and answer key.

Reading Passage

The Vast Ocean

Have you ever been to the ocean? Have you collected tiny shells that washed up on the endless shore? The ocean is one of Earth’s most remarkable features. The four oceans — the Pacific, the Atlantic, the Indian, and the Arctic — cover about 71% of Earth’s surface. Together, their area is approximately 140 million square miles.

The Pacific Ocean is the largest, covering more area than all the land on Earth combined. The Atlantic Ocean is the second largest and is known for its strong currents that affect weather in Europe and North America. The Indian Ocean is the warmest of the four. The Arctic Ocean, surrounding the North Pole, is the smallest and shallowest.

Scientists divide the ocean into zones based on depth and light. The sunlit zone near the surface is where most marine life is found, because sunlight allows plants to grow. Deeper down is the twilight zone, where light is very faint. The midnight zone is completely dark and extremely cold. Despite the harsh conditions, remarkable creatures live in every layer.

Humans have explored only a small fraction of the ocean’s depths. The Mariana Trench in the Pacific Ocean is the deepest known point on Earth, reaching about 36,000 feet below the surface. Scientists continue to discover new species and learn more about our planet by exploring the ocean.

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