NCERT Book Class 7 Science (Curiosity) Chapter 7 Heat Transfer in Nature

Heat Transfer
7 in Nature
Pema and her brother Palden reside in Gangtok. On a cold winter
evening, they are sitting around a fireplace. Palden shares his
experiences of visiting Kerala during the winter vacation. He
says that compared to Gangtok, winter in Kerala is comparatively
warm and humid. Both Pema and Palden are curious about why
some places are so cold and others quite hot.
Hearing them express their curiosity, their grandfather, a
retired science teacher, says, “Kerala is closer to the equator than
Sikkim and it also has a long coastline, which results in warmer
and more humid weather conditions”. Palden replies, “Yes, we
learnt in Grade 6 Science and Social Science that for us on the
Earth, the Sun is the main source of heat and light, and around
the equator, the climate is generally hot”.
As they are talking, Pema is keenly observing her grandmother
cooking thukpa (a traditional Sikkimese dish) in a large metal
pan. Pema asks, “Why are cooking utensils generally made of
metals?” Palden immediately responds that they had studied
in the chapter ‘The World of Metals and Non-metals’ that such
materials are good conductors of heat.