- Lesson #151: Lightning Rod
- Lesson #152: Glass Harmonica
- Lesson #153: Benjamin Franklin
- Lesson #154: Swivel Chair
Benjamin Franklin Inventions
Lightning Rod
Benjamin Franklin invented the lighting rod to protect buildings. He invented the lightning rod after making some studies with the Leyden jar. Lighting strikes were more common those days. People did not want to build tall buildings, only to have them struck by lightning. Lightning always strikes the highest object, so when you put a lightning rod on your building, the lightning goes to the highest point(, the rod), goes down the rod, through a wire, and into a ground rod where the bolt is discharged safely into the earth.
Glass Harmonica
The glass harmonica started as the glass harp, or a bunch wine glasses on a board, partially filled with water. The musician wets his/her fingers and rubs them in a circle on the rim of the glass to make a sound. Franklin tuned this whole operation on its side, and invented the glass harmonica. He reversed the turning so that the glass harmonica rotated and and the musician’s fingers stayed in place.
Benjamin Franklin’s Life
Franklin was born in Boston in 1706. Franklin did quite a bit of inventing. He invented the Franklin stove, bifocals, the lightning rod, and more. He had a lot of jobs at different times, for example, statesman, inventor, scientist, and farmer.
Thomas Jefferson Invention: Swivel Chair
Thomas Jefferson invented the swivel chair out of a regular chair. He wrote the Declaration Of Independence (1776) sitting in his swivel chair. He later sent it back to Monticello, where he added a writing paddle. It’s popularity increased, as Jefferson was famous for the Declaration. Swivel desk chairs are very common now, and I am even sitting in one as I write this essay.