Science Lesson Plan · Grades 4–6

Planet Mercury Lesson

Teach students about Mercury, the planet closest to the sun, with this printable science lesson. Covers Mercury’s short 88-day year, its unusually slow 59-day rotation, its heavily cratered moon-like surface, its lack of a protective atmosphere, and its extreme temperature range from very hot on the sun-facing side to extremely cold on the dark side. References the Mariner 10 spacecraft flybys in 1974–75. Includes comprehension questions and answer key.

Lesson Overview

Mercury: Closest Planet to the Sun

The lesson compares Mercury to Earth to help students grasp the scale of its differences — a year shorter than three Earth months, a day nearly 59 times longer than Earth’s, and surface temperatures that swing from over 400°C in sunlight to below −170°C in darkness. Without an atmosphere, there is nothing to retain heat or protect the surface.

The four-page lesson pairs a reading passage with comprehension questions. Students learn about the Mariner 10 mission that gave scientists their first close look at Mercury’s cratered terrain. A complete answer key is included.

How to Use This Lesson

1. Read the lesson passage together or have students read silently (pages 1–2). Ask students to list three ways Mercury differs from Earth.

2. Discuss why Mercury has such extreme temperatures despite being closest to the sun. Guide students to connect the lack of atmosphere to the temperature swings.

3. Assign the comprehension questions (page 3) independently. Review answers using the key on page 4.

Printable Resource

A classroom-ready PDF with everything in one printable resource.

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