TEACHGYAN • CLASS 7 SCIENCE • CURIOSITY
Chapter 12 — Earth, Moon, and the Sun
Solar System • Rotation • Revolution • Moon Phases • Eclipses
🌟 Chapter at a Glance
The Sun, Earth and Moon form a system in which motion and relative positions explain familiar phenomena such as day and night, phases of the Moon and eclipses.
☀️ 1. The Sun
The Sun is a star and the major source of light and heat for Earth. Earth receives solar energy that drives many processes, including weather and the water cycle.
🌍 2. Rotation and Revolution
Earth rotates about its axis. This rotation produces the regular cycle of day and night. Earth also revolves around the Sun; together with the tilt of Earth’s axis, its revolution is related to seasonal changes.
| Motion | Meaning | Major effect |
|---|---|---|
| Rotation | Spin about its axis | Day and night |
| Revolution | Motion around the Sun | Year; with axial tilt, seasons |
🌙 3. Moon and Its Phases
The Moon does not produce its own visible light; it reflects sunlight. As the Moon moves around Earth, the portion of its sunlit half visible from Earth changes. These changing appearances are called phases.
🌘 4. Eclipses
An eclipse occurs when the Sun, Earth and Moon become aligned closely enough for one body to block or shadow the light reaching another. A solar eclipse occurs when the Moon comes between the Sun and Earth. A lunar eclipse occurs when Earth comes between the Sun and Moon.
🛰️ 5. Models Help Us Understand Space
Space distances and motions are difficult to observe directly in a classroom. Globes, balls, lamps and diagrams can model relative positions and help us reason about shadows and illumination. A model is useful but is not a perfect scale copy of the real system.
🧠 Worked Examples
- Day and night are caused by Earth’s rotation, not by the Sun travelling around Earth each day.
- The Moon appears bright because it reflects sunlight.
- A lunar eclipse requires Earth to be positioned between the Sun and Moon.
🧩 Interactive MCQs
- Earth’s rotation is mainly responsible for: A day and night B Moon phases only C tides only D eclipses every month
- The Moon shines because it: A reflects sunlight B produces sunlight C burns fuel D is a star
- A solar eclipse occurs when the: A Moon is between Sun and Earth B Earth is between Sun and Moon C Sun is between Earth and Moon D Moon disappears
- A lunar eclipse occurs when: A Earth is between Sun and Moon B Moon is between Sun and Earth C Sun is between Earth and Moon D Earth stops rotating
Answers: 1-A, 2-A, 3-A, 4-A
📌 Case-Based Learning — Classroom Space Model
A class uses a lamp as the Sun, a large ball as Earth and a smaller ball as the Moon. Students move the Moon around Earth and observe the illuminated portions.
- Which object should represent the light source?
- How can the model demonstrate Moon phases?
- What alignment would demonstrate a lunar eclipse?
- Why should students not interpret the model as a perfect scale model?
🔥 HOTS / Competition Corner
- Why don’t solar and lunar eclipses happen every month?
- Explain why the Moon’s visible shape changes even though the Moon itself remains approximately spherical.
- Design a model that demonstrates day and night without changing the lamp position.
📝 Five-Level Worksheet
| Level | Task |
|---|---|
| 1 | Define rotation, revolution, phase and eclipse. |
| 2 | Identify the positions involved in day/night and eclipses. |
| 3 | Explain Moon phases using a diagram. |
| 4 | Analyse a Sun-Earth-Moon model. |
| 5 | Design and explain a classroom model of the Earth-Moon-Sun system. |
🏆 Mastery Checklist
- ☐ I can distinguish Earth’s rotation and revolution.
- ☐ I can explain day and night.
- ☐ I can explain Moon phases.
- ☐ I can distinguish solar and lunar eclipses.
- ☐ I can use a model to explain space phenomena.
🔁 One-Minute Revision
Earth rotates → day and night. Earth revolves around the Sun → a year; axial tilt contributes to seasons. The Moon reflects sunlight → phases. Relative alignment of Sun, Earth and Moon → eclipses.