Summary:
- Mark Twain was a steamboat pilot on the Mississippi River for a period of time.
- He took his pen name from the measurement of water depth (twelve feet, which was a safe depth for the boats) The boats got their power from steam – liquid water converted to a gas at high temperatures.
- A change of state can be brought about by putting heat into a system or removing it from the system.
- The temperature of a system will not change as long as the substance is a liquid or liquid as well as the reverse.