Insert the prepositions wherever necessary.

1. Thermodynamics deals ______ the conversion ______ mechanical energy _____ thermal energy. 2. The production ______ heat _____mechanical means may be illustrated ______ the phenomenon ______ friction. 3. A heat engine is a machine ______ transforming heat _______ mechanical energy. 4. To transform energy ______ any ______ its numerous forms ______ heat is a comparatively simple process. 5. ______the case ______ the ideal reversible process, there is no change ______ the quantity ______ available energy. 6. No change ______ a system ______ bodies that takes place ______ itself can increase the available energy ______ the system. 10. Make up dialogues on the following topics using the introductory and connective words.