How is the Lunar Eclipse Formed?

Content Standards

Students understand the positions of the Earth, Moon, and Sun.
They explore how a lunar eclipse occurs when Earth blocks sunlight from reaching the Moon.
They differentiate between lunar and solar eclipses.

Performance Standards

Students will be able to:

Identify the alignment of Earth, Moon, and Sun during a lunar eclipse.
Explain why a lunar eclipse does not occur every full moon.
Differentiate between total, partial, and penumbral lunar eclipses.
Relate the concept with real-life observation of eclipses.

Alignment Standards

Reference:

The lesson is aligned with the NCERT Grade 7 Science – Chapter 12 : Earth, Moon, and the Sun, Section : 3 How Lunar Eclipse is formed?

Learning Objectives

By the end of the lesson, students will be able to:

Understand rotation & revolution of Earth and Moon.
Explain the positioning of the Sun, Earth, and Moon during a lunar eclipse.
Differentiate types of lunar eclipses (total, partial, penumbral).
Explain why a lunar eclipse doesn’t occur every full moon.
Relate scientific reasoning with real-life observations and overcome superstitions

Prerequisites (Prior Knowledge)

Basic understanding of Earth’s rotation and revolution.
Knowledge that the Moon revolves around Earth and reflects sunlight.
Awareness of day and night caused by Earth’s rotation.

Introduction

In this session, students will explore the fascinating phenomenon of lunar eclipse. They will understand how the positions of Earth, Sun, and Moon cause the Moon to appear dark. With visual aids, they will connect textbook knowledge with real-life sky events.

Timeline (40 Minutes)

Title	Approximate Duration	Procedure	Reference Material
Engage	5	Ask: Why does the Moon sometimes turn red? If the Moon shines because of sunlight, what happens when Earth comes in between the Sun and the Moon? Demonstration: Switch on a torch (Sun), place a football (Earth) in front, and a tennis ball (Moon) behind it. Ask: “What happens to the Moon when Earth blocks the light?”	Slides
Explore	10	Virtual Lab	Slides and VR lab
Explain	10	Teacher explains with the help of XR visuals: Motions of Earth and Moon: Rotation, Revolution, Phases. Lunar Eclipse Formation → Sun → Earth → Moon in one line. Types of Lunar Eclipses: Total: Moon passes through Earth’s umbra (appears red). Partial: Only part of the Moon enters the umbra. Penumbral: Moon enters penumbra, appears slightly dim. Why not every full moon? → Moon’s orbit tilted 5°.	Slides and Virtual Lab
Evaluate	10	1.Conduct a MCQ to check understanding of the key concepts.	Virtual Lab
Extend	5	Scenario thinking: If Earth had no atmosphere, how would this look different? If the Moon’s orbit was not tilted, how often would we see eclipses?”	Slides

How is the Lunar Eclipse Formed?

Introduction

Have you seen the Moon sometimes turn dark or red when it’s full? That’s a lunar eclipse — it happens when Earth comes between the Sun and the Moon and casts a shadow on the Moon. Because the Moon’s orbit is tilted, this alignment doesn’t happen every month.

Theory

Motions of Earth & Moon

Rotation: Earth spins once around its own axis in about 24 hours → causes day and night.
Revolution: Earth revolves around the Sun once in about 365 days → causes seasons.
The Moon also revolves around Earth (≈ 27.3 days) and rotates on its axis at almost the same rate → hence the same side of the Moon always faces Earth.

Why the Moon Shines?

The Moon does not produce its own light.
It shines by reflecting sunlight.
When Earth’s shadow blocks this light, the Moon may appear dim or red.

What is a Lunar Eclipse?

A lunar eclipse occurs when Earth comes between Sun and Moon, and Earth blocks the sunlight which normally falls on the Moon.
This can only happen during a full moon phase.

Types of Lunar Eclipses

Total lunar eclipse: Entire Moon enters Earth’s umbra (the dark central part of its shadow). The Moon often appears red.
Partial lunar eclipse: Part of Moon enters umbra; rest of it is in penumbra or untouched.
Penumbral lunar eclipse: Moon only passes through Earth’s penumbra (lighter outer shadow), causing only subtle dimming.

Why Lunar Eclipses Are Not Monthly?

The Moon’s orbit is tilted by about 5° relative to Earth’s orbit around the Sun.
Because of that tilt, during many full moons, the Moon passes a little above or below Earth’s shadow → no eclipse.
Only when the full moon happens near alignment (at lunar nodes) do we get a lunar eclipse.

Why the Moon Looks Red in a Total Eclipse?

Earth’s atmosphere refracts (bends) sunlight.
Blue/shorter wavelengths are scattered out more; red/orange light bends through and reaches the Moon.
The effect is similar to sunset/sunrise colors.

Comparison: Lunar vs Solar Eclipse

Feature	Lunar Eclipse	Solar Eclipse
When in lunar phase	Full Moon	New Moon
Blocker	Earth between Sun & Moon	Moon between Sun & Earth
Visibility	Seen by many people wherever it is night on Earth	Seen in a much smaller area (path of Moon’s shadow)
Duration	Several hours possible	Usually few minutes of totality

Vocabulary

This is the list of vocabulary terms used throughout the lesson.

Term	Definition
Axis	An imaginary line through Earth (North–South poles) around which Earth rotates.
Orbit	The path one body takes around another (e.g. Moon around Earth, Earth around Sun).
Rotate / Rotation	Spinning of a body (Earth or Moon) on its axis.
Revolve / Revolution	Movement of a body completely around another body (Moon around Earth, Earth around Sun).
Full Moon	Lunar phase when the Moon is opposite the Sun from Earth and its face is fully illuminated.
New Moon	Phase when the Moon is between Earth and Sun; its illuminated side is away from Earth, so we don’t see it.
Shadow	Area behind an object where light is fully or partially blocked.
Umbra	The darker central region of a shadow where light is completely blocked.
Penumbra	The lighter outer region of a shadow where light is only partially blocked.
Lunar Eclipse	An event when the Earth comes between the Sun and Moon, casting its shadow on the Moon.
Total Lunar Eclipse	When the whole Moon passes through Earth’s umbra.
Partial Lunar Eclipse	When only part of the Moon passes through the umbra.
Penumbral Lunar Eclipse	When the Moon passes only through the penumbra and not into the umbra.
Syzygy	An alignment of three celestial bodies (Sun, Earth, Moon) in a straight line.
Celestial	Relating to the sky or outer space.
Phenomenon	A fact or event observed, especially one whose cause or explanation is in question.

How is the Lunar Eclipse Formed?

Introduction

In this XR/VR experience, students explore how a lunar eclipse occurs when Earth comes between the Sun and the Moon, casting a shadow on the Moon. By interacting with models and observing real-time simulations, learners understand the positioning of celestial bodies, different types of lunar eclipses, and why eclipses don’t happen every month.

Key Features

3D Interactive VR Environment showing Sun, Earth, and Moon alignment.
Dynamic Shadow Simulation to demonstrate umbra and penumbra formation.
Step-by-step breakdown of total, partial, and penumbral eclipses.
Orbit Tilt Demonstration explaining why eclipses are rare.
Blood Moon Effect visualized in real-time.
Quiz at the end for quick self-evaluation and revision.

Step-by-Step Procedure for VR Experience

Step 1: Enter the Virtual Lab

Students enter a 3D VR environment showing the Sun, Earth, and Moon in space.

Step 2: Celestial Bodies involved in Lunar Eclipse

Labels and brief descriptions appear to explain the Sun, Earth, and Moon, and their significance in the Lunar Eclipse.

Step 3: Explore Lunar Eclipse

Observe the position of the celestial objects and see the BLOOD Moon Effect.

Step 4: Evaluation

After interaction, students proceed to the quiz:
- 3 MCQs