Activity 4.1 heat science class 7 chapter 4
Activity 4.1 asks us to put one hand in cold water, another in cold water for some time and check how it feels when we put both hands in mixed water.
Here we feel different in both hands. The hand which was in hot water now feel cool in mixed water; while the other hand feel hot in mixed water.
Heat and cold are relative terms. For example, 40°C is hotter than 30°C but is colder than 50°C. A similar thing happens to our body and hands. We detect cold and warm through the same sensors present in our skin. Once our hand is in hot water, it feels chilly when we place the same hand to a slightly less hot mixture that is a mixed solution.
Next: Activity 4.2 Heat.
See also: Paheli Boojho Answer Chapter 4 Heat.
Exercise Solution Heat Class 7 Science Chapter 4.