Final Answer:
1. Newton observed an apple falling and used that to develop his law of universal gravitation, explaining that a force called gravity pulls objects toward Earth’s center.
Title: *How Newton Discovered Gravity from a Falling Apple*
2. Einstein and Hungarian scientists warned Roosevelt about Nazi atomic research, prompting the U.S. to build the atomic bomb—something Einstein later regretted as his greatest mistake.
Title: *Einstein’s Warning That Led to the Atomic Bomb—and His Regret*
3. Copernicus proposed the heliocentric (sun-centered) model of the universe, but delayed publishing it likely to avoid conflict with the Catholic Church, which still believed Earth was the center.
Title: *Why Copernicus Waited Centuries to Share His Sun-Centered Universe Idea*
Parent Tip: Review the logic above to help your child master the concept of main idea worksheets.
