Activity 2.5 Class 9 Science|Is Matter Around Us Pure
In this
post, you will find NCERT Science Class 9 Chapter 2 Activity solutions. In
Class 9 science chapter 2 Is Matter Around Us Pure consists of NCERT Activity
2.5 Class 9 Science Explanation with a conclusion.
Activity 2.5 NCERT Class9 Science Is Matter Around Us Pure
You are
suggested to study NCERT activity 2.5 class 9 science Is matter around us pure
explanation with a conclusion so that you can attempt questions based on the
activity 2.5 class 9 science. Activity 2.5 class 10 science will be very useful
for you.
Activity
2.5 Class 9 Science
·
Take some full cream milk in a test tube.
·
Centrifuge it by using a centrifuging machine for two minutes. If a
centrifuging machine is not available in the school, you can do this activity
at home by using a milk churner, used in the kitchen.
·
If you have a milk dairy nearby, visit it and ask (i) how they separate
cream from milk and (ii) how they make cheese (paneer) from milk.
After performing the activity, answer the following questions
1 What do you observe on churning the milk?
2 Explain how the separation of cream from milk takes place?
Observation
Activity 2.5 Class 9 Science
When we centrifuge
the cream milk or churn with a churner, fat or cream floats on the surface of
the milk.
Explanation
Activity 2.5 Class 9 Science
Centrifugation
is based on the principle when a machine
or churner rotates at a very high speed then the denser solid particles
settle down faster and lighter particles float on the surface of the liquid.
So, particles
of cream are lighter so float on the surface.
Conclusion
Activity 2.5 Class 9 Science
This activity
is based on the difference between densities(high or low) of particles of the mixture
Answer to
the above questions
1.
On churning the milk, the solid denser particles remain at the bottom
and lighter particles are collected at the top of the test tube.
2. The milk is rotated at high speed in a container. The cream is separated and floats on the surface. This happens due to the difference between
the densities of the particles present in the mixture.
Related Topics for you
1. Next Activity - Activity 2.6 Class 9 Science
2. Previous Activity-Activity 2.4 Class 9 Science
