Chapter IV review and final summary
Chapter IV dealt with heat phenomena. Heat is energy (J); its sources: the Sun, combustion, electric current, friction. Bodies expand when heated and contract when cooled (the distance between molecules changes); gases expand most, solids least; water contracts from 0 to 4 °C and is densest at 4 °C. Heat transfer: conduction (in solids; metals conduct well), convection (in liquids and gases), radiation (even in a vacuum; black surfaces absorb well). A thermos reduces all three. Al-Farabi linked temperature to the motion of particles; Beruni and Ibn Sina explained climate by the slant of sunlight. Temperature is measured with a thermometer on the Celsius scale: 0 °C — melting ice, 100 °C — boiling water, lower limit −273.15 °C. A medical thermometer covers 35–42 °C, the body is 36.6 °C. In all these processes energy is not lost, only transferred or converted.
“Heat quiz”: teams answer Chapter IV questions (type of transfer, expansion example, thermometer rule); points for each correct answer, and each answer must include an example.