Henry Hudson discovered Hudson Bay in 1610. Aboard the Discovery, he felt the bay might really be the Northwest Passage to the Pacific Ocean. In November his ship became icebound in the bay, and the men wintered on shore. The next year his crew mutinied, and he, his son, and some crew members were set adrift in a small boat. Children can learn more at: Henry Hudson.
Declaration of Independence was officially signed in 1776. Most people believe the Declaration was signed July 4, 1776. However, only John Hancock and Charles Thompson signed a draft on that day. Fifty delegates were at the official signing on August 2. Five more people signed the document before the end of the year. One more person signed it the next year.
Census was taken in the United States for the first time in 1790. Idea: Children could take a mock census in their classrooms. Children could also learn more at: https://www.census.gov/schools/.
Positron was discovered by Carl D. Henderson in 1932. The positron is the anti-particle to the electron.