Lesson 60-65

Bonjour, today we will be learning about jackhammers, pin-tumbler locks, safety pins and the gyroscopes. Sounds delightful.

Jackhammers (Lesson 61)

Early jackhammers, inspired by the steam engine. It was developed by 1806. Jonathan Couch invented the modern jackhammer in 1848. Jackhammers can run on electricity. It slits rock and concrete.

Pin-Tumbler Locks (Lesson 62)

Linas Yale, Sr was born in Connecticut in 1797. He invented the pin-tumbler lock in 1843. The key lines up easy to the re-key.

Safety Pin (Lesson 63)

Walker Hunt was born in New York in 1796. Hunt invented a version of the sewing machine in 1832. He invented the safety pin in 1849. Safety Pin are simple fading needles.

Gyroscopes (Lesson 64)

Leon Foucault was born in Paris in 1819. He invented the gyroscopes in 1852. Gyroscope is a sinning disc set inside gimbals. Gimbals allow rotation. It resist forces that try to turn them. The gyroscopic compass was built in 1904.