What is the difference between James Watt and Thomas Newcomen steam engines?

James Watt's steam engine improved upon Thomas Newcomen's design primarily by introducing a separate condenser, which increased efficiency by allowing the steam engine to operate at a lower temperature and pressure. While Newcomen's engine used steam to create a vacuum and drive a piston, it was relatively inefficient and consumed a lot of fuel. Watt's modifications also included a rotary motion, making his engine more versatile for various applications. Overall, Watt's innovations significantly advanced steam engine technology and contributed to the Industrial Revolution.