HEAT AND ITS EFFECTS-CLASS 07-CBSE-SCIENCE-SUPER NOTES-BEST NOTES FOR EXAMS
HEAT is a form of energy which causes sensation of hotness or coldness. Heat is measured in joules or calories . S. I. Unit of heat is joule. 1 kilojoule (KJ) = 1000 joules (J) 1 kilocalorie (KC) = 1000 calories (C) 1 cal= 4.184 J Effects of heat 1. Heat causes expansion. 2. Heat causes change in temperature. 3. Heat causes change in state. 1. Heat causes expansion All substances expand on heating and contract on cooling. Expansion in solid Molecules in solids are closely packed together and their positions are fixed . The space between the molecules of solids are almost negligible and the force of attraction between them is very strong . These molecules only vibrate in their mean positions. While heating, the movement of these particles increases result in an increase in dista...