NCERT Book Class 9 Science (Exploration) Chapter 4 Describing Motion Around Us

Chapter
Describing Motion
4 Around Us

Think It Over Everything in nature is in motion, from massive astronomical
objects to subatomic particles. And what a variety in motion we
y How much distance have in nature — flitting butterflies, slithering snakes, hopping
should we maintain hares, galloping horses, tendrils of climbers twinning around a
from the truck support, closing of flytraps, dancing dust particles in a sunbeam,
ahead to avoid
smoke particles moving in air, rising and falling of ocean tides, and
a collision if it
suddenly applies the gathering clouds!
brakes? Isn’t motion in nature wonderful? But how do we study the
y Does this distance wide variety of complex motions around us? As you have read in
depend upon the the first chapter, to explore a complex phenomenon, scientists first
speed with which study it in its idealised simplified forms. Such types of motion are
we are moving?
linear, circular, and oscillatory about which you learnt in Grade 6
earlier grades. In this chapter, you will learn more about Curiosity
Chapter 5
linear motion (motion in a straight line) and uniform
circular motion.
Earlier, you learnt about some physical quantities, Grade 7
Curiosity
such as distance, time and speed. Now, you will learn Chapter 8