Easy:
1. What invention, initially used for communication, is now ubiquitous in everyday life? (Answer: The telephone)
2. What was the first animal to orbit Earth? (Answer: Laika, a Soviet dog)
3. Who developed the first working steam engine? (Answer: Thomas Newcomen)
4. What revolutionary scientific theory did Albert Einstein propose? (Answer: Theory of Relativity)
5. Which scientist discovered the laws of motion and universal gravitation? (Answer: Isaac Newton)
Medium:
1. What year did the first successful human spaceflight take place? (Answer: 1961)
2. Who invented the World Wide Web? (Answer: Tim Berners-Lee)
3. What breakthrough allowed for the development of the transistor? (Answer: The discovery of the semiconductor)
4. What medical breakthrough eradicated smallpox, a devastating disease? (Answer: The development of the smallpox vaccine)
5. What was the first artificial satellite to orbit Earth? (Answer: Sputnik 1)
Hard:
1. What was the name of the first programmable computer? (Answer: The Analytical Engine, designed by Charles Babbage)
2. What groundbreaking invention allowed for the mass production of automobiles? (Answer: The assembly line, pioneered by Henry Ford)
3. What scientific breakthrough led to the development of nuclear power? (Answer: Nuclear fission)
4. Who was the first woman to fly solo across the Atlantic Ocean? (Answer: Amelia Earhart)
5. What is the name of the first successful human heart transplant? (Answer: Performed by Christiaan Barnard in 1967)
Bonus:
1. What was the name of the first space shuttle? (Answer: Columbia)
2. What was the first successful flight of a heavier-than-air flying machine? (Answer: The Wright brothers' flight at Kitty Hawk, NC in 1903)
These are just a few examples, and there are many other fascinating milestones in science and technology. Enjoy exploring!