Explain Activity 1.5 NCERT Science Class 9

Activity 1.5 Explanation NCERT Science Class 9 Matter In Our Surroundings

Brief procedure:

Activity 1.5 asks us to put copper sulphate in hot water and cold water respectively and, observe the time it takes to dissolve.


Copper sulphate in hot water diffuses fast and dissolves faster than in a beaker containing cold water.


Activity 1.5 Explanation NCERT Science Class 9
Copper sulphate in crystal form.

All substances have some kinetic energy in it. When we heat a substance its kinetic energy increases. Heating water results in an increase in its kinetic energy, as a result, we see that copper sulphate crystal dissolves in much lesser time.


This experiment proves that heating increases the diffusion rate of a substance.


You can apply this rule on many objects. Sugar in cold water takes more time to dissolve, while in hot water it dissolves in no time.

Increase in kinetic energy changes the physical state of a substance. For example, heating copper to around 1100°C can make it liquid. A coppersmith utilizes this property to make a statue. He puts liquid copper into a mould and a statute forms.

Next: Arrangement of molecules in a substance: Activity 1.6 NCERT Science Class 9 Chapter 1.

See also:

Experiment to demonstrate different substance take different time to dissolve: Activity 1.4.

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