In the chapter's own words, what are 'the phases of the Moon'?
Hint. The definition sits right after the waxing/waning discussion in section 11.1.1.
✦ 'The changing shapes of the bright portion of the Moon from one day to another as seen from the Earth are called the phases of the Moon.'
Define the waxing and waning periods of the Moon, and name their Indian terms.
Hint. One period is bright-portion-shrinking, the other is bright-portion-growing — match each to its Sanskrit-derived name.
✦ The waning period is the roughly two-week stretch after full Moon when the bright portion shrinks to nothing at new Moon — and, because the bright portion is shrinking, in India this is called Krishna Paksha. The waxing period is the roughly two-week stretch after new Moon when the bright portion grows back to a full circle — in India this is called Shukla Paksha. The cycle alternates between the two in a continuous loop, one full Moon to the next taking about a month.
Distinguish Purnima from Amavasya.
Hint. One is the day of the full bright circle, the other the day it disappears entirely.
✦ Purnima (full Moon day) is when the Moon appears as a full bright circle; Amavasya (new Moon day) is when the Moon's bright portion is not visible at all.
Why is the full Moon nearly opposite the Sun in the sky, such that it rises around when the Sun sets?
Hint. Think about which side of the Moon has to face Earth for us to see its ENTIRE illuminated half at once.
✦ We see the Moon's full illuminated face only when Earth is positioned between the Sun and the Moon along their shared line, so the Moon and Sun sit on nearly opposite sides of the sky as seen from Earth — which is exactly why, on a full Moon day, the Sun rising in the East coincides with the Moon almost setting in the West, and vice versa at sunset.
At what phase is the Moon overhead at sunrise, and why is that useful to know?
Hint. The chapter states this exact fact while tracking the Moon's shifting position across the waning fortnight.
✦ 'When the bright part of the Moon decreases to a half circle shape, the Moon is overhead at Sunrise.' This is why knowing the current phase alone lets an observer predict roughly where to look for the Moon on a given morning.
A step further: many people believe the Moon always rises exactly when the Sun sets. Is this true, and what does checking real moonrise times over several days reveal?
Hint. The chapter points to checking newspaper or Positional Astronomy Centre moonrise timings across consecutive days — what pattern shows up?
✦ No — this is a common misconception. Checking actual moonrise times over consecutive days shows the Moon rises about 50 minutes later each day, so it is frequently NOT rising exactly at sunset; moonrise can even fall in the afternoon (around 2:00–4:00 p.m.), letting the Moon be spotted in the eastern sky in broad daylight, roughly 30 minutes after the listed moonrise time once it has climbed high enough to see.
Solutions written by the tuition.in editorial team and checked against NCERT Curiosity — Textbook of Science for Grade 8, Chapter 11 (hecu111.pdf), Reprint 2026-27, pages 170-189. Questions are referenced from the NCERT textbook for identification.
Pair self-study with a tutor, a live course or a coaching centre.
