Explain Activity 1.3 NCERT Science Class 9

Activity 1.3 Explanation NCERT Science Class 9 Matter In Our Surroundings

Brief procedure: 

Activity 1.3 asks us to know about diffusion by comparing the smell of a burning incense stick with a non-burning incense stick.


We can smell the perfume of a burning incense stick from the far way location; while to smell a non-burning incense stick we need to go near to it.

Activity 1.3 Explanation NCERT Science Class 9
A burning incense stick lets its volatile particles escape and mix in air.

The difference in diffusion rate depends on the kinetic energy of the substance and the medium. Gas has high kinetic energy. Particles in the air are continuously moving in all directions. When we burn an incense stick, its volatile perfume mixes in air and start spreading fast into the surrounding. As a result, we can observe the smell of the burning incense stick from a long distance.

Order of kinetic energy: Sold<Liquid<Gas

Related facts:

Diffusion: We call this process of spreading of particles in a medium ‘Diffusion‘. Diffusion is a natural phenomenon and never stops. In our daily life, we make use of diffusion in many places. We add sugar in water to make tea or juices; here sugar molecule diffuses into the water through diffusion. A plant produces oxygen; this oxygen diffuse into the air and we get oxygen for breathing.

Next: Experiment to demonstrate different substance differ in diffusion rate: Activity 1.4.

Read also:

Experiment to show a particle consist of millions of smaller particles: Activity 1.2.


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