How is the Solar Eclipse Formed?

Content Standards

Students understand that eclipses are alignment events involving the Sun, Earth, and Moon, where shadows cause the Sun to be obscured (solar eclipse) or the Moon to darken (lunar eclipse). They recognise how orbital tilt, umbra/penumbra, and apparent size determine what observers see (total, partial, annular, penumbral).

Performance Standards

Students will be able to:

Identify the correct line-ups for solar (Sun → Moon → Earth) and lunar (Sun → Earth → Moon) eclipses.
Explain why eclipses are not monthly (Moon’s orbital tilt and node alignment).
Distinguish umbra vs penumbra and relate them to total/partial/penumbral views.
State and follow safe solar-viewing practices (projection/approved filters).

Alignment Standards

Reference: NCERT Book Alignment

The lesson is aligned with the NCERT Grade 8 Science Textbook, Chapter 12: Earth, Moon, and the Sun, Section: 12.3.1 Solar eclipse

Learning Objectives

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

Describe, step by step, how solar and lunar eclipses occur.
Use apparent size to explain total vs annular solar eclipses.
Interpret umbra and penumbra and predict what an observer sees in each.
Outline safe solar-viewing approaches and when to use them.

Prerequisites (Prior Knowledge)

Basic ideas of orbits and phases (Moon around Earth; Earth around Sun).
Light travels in straight lines; shadows form behind objects.
Awareness that the Moon’s orbit is tilted relative to Earth’s orbit.

Introduction

In this session, students will explore the celestial alignments that cause solar and lunar eclipses, understanding why the Moon’s tilt prevents monthly occurrences. They’ll also learn how the Moon’s apparent size determines whether a solar eclipse appears total or annular, and discover essential safety practices for viewing these rare events.

Timeline (40 Minutes)

Title	Approximate Duration	Procedure	Reference Material
Engage	5	Hook with a totality clip or image. Prompt: “What must line up for the Sun to disappear in daytime?” Elicit Sun–Moon–Earth and set the goal: understand what different places on Earth see.	Slides
Explore	10	Shadow modelling. Using a torch (Sun), a small ball (Moon), and a globe (Earth), demonstrate the umbra (narrow totality) and penumbra (wider partial) on the globe. Learners predict what an observer in each region would see.	Slides
Explain	10	Build the concept. Define solar eclipse; contrast total vs partial vs annular using apparent size (Moon sometimes looks slightly smaller → ring). Explain why not monthly (orbital tilt; nodes). Emphasize safety: projection or certified solar filters only.	Slides + Virtual Lab
Evaluate	10	Students will attempt the Self-Evaluation task on LMS.	Virtual Lab
Extend	5	Apply & reflect. “If our town lies outside the umbra but inside the penumbra, what should we expect and how should we watch safely?” Share one correct safe-viewing method before closing.	Slides

How is the Solar Eclipse Formed?

Introduction

In this session, you will explore how a solar eclipse occurs when the Moon passes between the Sun and Earth, casting its umbra and penumbra on Earth’s surface. You will use alignment and apparent-size ideas to explain total, partial, and annular views, and apply safe solar-viewing methods (projection or certified filters).

Theory

Why learn this?

Have you seen videos where daylight fades to twilight for a few minutes?
Why does the Sun sometimes look like a dark disc with a bright ring?

Real-life link:
A solar eclipse is an alignment event. Knowing how line-ups and shadows work makes viewing safe and scientific.

This leads to the need to understand Sun–Moon–Earth alignment, umbra/penumbra, apparent size (total vs annular), and safe viewing methods.

A solar eclipse happens when the Moon passes between the Sun and Earth, and the Moon’s shadow falls on parts of Earth.

Key components:

Alignment: Sun → Moon → Earth (daytime event on Earth).
Shadows:
- - Umbra — dark, central shadow; observers here see totality.
  - Penumbra — lighter outer shadow; observers here see a partial eclipse.
Apparent size: The Moon can look the same size as the Sun because it is much closer; small distance changes decide total vs annular.

Quick example:
If the Moon appears slightly smaller than the Sun, a bright ring (annulus) remains — an annular solar eclipse.

Steps / Process / Rules

Solar eclipse process

Line-up occurs: Sun–Moon–Earth nearly in a straight line.
The Moon’s umbra sweeps a narrow path across Earth → total solar eclipse for observers along this path.
The penumbra covers a wider area → partial eclipse for nearby regions.
If the Moon is a little farther from Earth (appears smaller), the umbra does not reach the surface → annular eclipse (bright ring).

Why not every month?
The Moon’s orbit is tilted relative to Earth’s orbit, so perfect line-ups only happen near the nodes (where the orbits cross).

Solved examples

Q: What decides total vs annular solar eclipse?
A: The Moon’s apparent size. If it appears larger than the Sun → total. If smaller → annular (ring).
Q: What do people see outside the umbra but inside the penumbra?
A: A partial solar eclipse.

Applications / Why is it useful?

Safe viewing: use pinhole projection or certified solar filters (never look at the Sun directly).
Science opportunity: totality reveals the Sun’s corona and allows measurements not possible on normal days.
Geography/time links: helps explain why some places see totality while others see partial or none.

Vocabulary

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

Solar eclipse: the Moon blocks sunlight and casts a shadow on Earth.
Umbra: darkest, central shadow; total eclipse for observers here.
Penumbra: lighter outer shadow; partial eclipse for observers here.
Annular eclipse: Moon appears slightly smaller; a bright ring remains.
Totality: brief period when the Sun’s disc is fully covered.
Corona: the Sun’s hot outer atmosphere, visible during totality.
Nodes: points where the Moon’s orbit crosses Earth’s orbital plane.
Apparent size: how big an object seems due to distance and actual size.
Alignment: near-straight arrangement Sun–Moon–Earth causing the eclipse.

How is the Solar Eclipse Formed?

Introduction

This VR lab guides you through the Sun, Earth, and Moon to show how a solar eclipse is formed. You will read short on-screen notes and move through the scenes in order to see where each body is and what people on Earth observe during an eclipse.

Key Features

Clear, step-through screens with a Next button for easy navigation.
Short captions and large visuals that show the Sun, Earth, Moon, and their line-up.
Consistent icons/labels so you can recognize each body quickly.
Quick quiz at the end for a fast self-check (if enabled in your build).

Step-by-Step Procedure for VR Experience

Access the Virtual Lab using the provided link and press Start.
Follow the on-screen instructions on each screen and press Next to continue.
For Informative (this lab): browse the step-by-step screens below.
Screen: Introduction
Read: “Get introduced to the planets involved with the happening of solar eclipses.”
Action: Press Next.
Screen: Moon
Read: “Blocks Sun in solar eclipse. Tilt prevents monthly eclipse.”
Action: Press Next.
Screen: Earth
Read: “Orbits Sun, aligns with Moon.”
Action: Press Next.
Screen: Sun
Read: “Gives light for eclipses. Appears Moon-sized from Earth.”
Action: Press Next.
Screen: Transition
Read: “Let’s look at the positions of the celestial bodies during a solar eclipse.”
Action: Press Next.
Screen: Solar Eclipse
Use slider to adjust the Moon’s orbit and switch the view from the Earth for proper view.
Quiz (2 MCQs): Answer the MCQs and submit.