Steam engines are external combustion engines, where the working fluid is separate from the combustion products. Non-combustion heat sources such as solar power, nuclear power or geothermal energy may be used. The ideal thermodynamic cycle used to analyze this process is called the Rankine cycle. In the cycle, water is heated and transforms into steam within a boiler operating at a high pressure. When expanded through pistons or turbines, mechanical work is done. The reduced-pressure steam is then condensed and pumped back into the boiler. 

The first commercially successful true engine, in that it could generate power and transmit it to a machine, was the atmospheric engine, invented by Thomas Newcomen around 1712. It was an improvement over Savery's steam pump, using a piston as proposed by Papin. Newcomen's engine was relatively inefficient, and in most cases was used for pumping water. It worked by creating a partial vacuum by condensing steam under a piston within a cylinder. It was employed for draining mine workings at depths hitherto impossible, and also for providing a reusable water supply for driving waterwheels at factories sited away from a suitable "head". Water that had passed over the wheel was pumped back up into a storage reservoir above the wheel.

What are the answers to this following set of questions:

1. What is a true engine?
2. What does it mean to be a "true engine"?
3. Who made the first successful one?
4. Was that in the 19th century?
5. When?
6. Was it any better than the previous steam pump?
7. What made it better?
8. Whose idea was that?
9. What was this engine used for mostly?
10. Where was it used?
11. Anywhere else?
12. Was it an efficient engine?
13. What kind of engine would a steam engine be classified as?
14. Is the fluid in the same compartment as the combustible ingredients?
15. Could a steam engine work with nuclear power?
16. What about energy from the sun?
17. How about from the moon?
18. What is the perfect thermodynamic cycle called?
19. What happens to the water in this cycle?
20. Does it change form?

Numbered answers:
1. atmospheric engine
2. it could generate power and transmit it to a machine
3. Thomas Newcomen
4. no
5. around 1712
6. yes
7. used a piston
8. Papin
9. pumping water
10. mine workings
11. factories
12. no
13. external combustion engines
14. no
15. yes
16. yes
17. unknown
18. Rankine cycle
19. water is heated
20. yes