Who invented the steam engine?

The correct answer is James Watt. He is credited with significantly improving the design of the steam engine in the 18th century, which played a vital role in the Industrial Revolution. While steam engines existed before Watt, his enhancements, such as the separate condenser, made them much more efficient and practical for use in various industries, including mining and manufacturing.

George Stephenson is known for developing the first successful steam locomotive, which further advanced the use of steam power in transportation, but he did not invent the steam engine itself. Isaac Newton made foundational contributions to physics and mathematics but was not involved in the development of the steam engine. Thomas Edison is primarily associated with electric power and inventions like the light bulb and phonograph, rather than steam engine technology.