CBSE NCERT Solutions for Class 7 Science Chapter 4

The answers for NCERT questions are given in a very easy to understand the language to help students easily comprehend them. Step by step solutions are provided for the numerical questions.

CBSE NCERT Solutions for Class 7 Science Chapter 4:

Question-1:

Discuss why wearing more layers of clothing during winter keeps us warmer
than wearing just one thick piece of clothing.

Solution:

We wear more layers of clothing during winter to keeps us warmer than wearing just one thick piece of clothing because because air gets trapped in between the two layers of blankets. This air prevents the flow of heat from our body to the cold
surroundings as air is bad conductor of heat.

Question-2:

State similarities and differences between the laboratory thermometer and the
clinical thermometer.

Solution:

Similarities:
(i) Both made up of uniform glass tube.
(ii) Both contain mercury.
(iii) Both have bulb at one end.
(iv) Both generally have Celsius scale.
Differences:
(i) Range of laboratory thermometer is from -10°C to 110°C while range of clinical
thermometer is from 35°C to 42°C.
(ii) Laboratory thermometer is used to take the reading of temperature in laboratory
while clinical thermometer is used to measure the temperature f human body.
(iii) Mercury level falls when removed from the source in case of laboratory
thermometer while in case of clinical thermometer

Question-3:

A wooden spoon is dipped in a cup of ice cream. Its other end
(a) becomes cold by the process of conduction.
(b) becomes cold by the process of convection.
(c) becomes cold by the process of radiation.
(d) does not become cold.

Solution:

(d) does not become cold. Wood is a bad conductor of heat.

Question-4:

Stainless steel pans are usually provided with copper bottoms. The reason for
this could be that
(a) copper bottom makes the pan more durable.
(b) such pans appear colorful.
(c) copper is a better conductor of heat than the stainless steel.
(d) copper is easier to clean than the stainless steel.

Solution:

(c) copper is a better conductor of heat than the stainless steel.