I learned about one invention and three inventors. The invention is called calculus. The two inventors are Christiaan Huygens, Anton Van Leeuwhoek, and Isaac Newton. First, I learned about Christiaan Huygens. He discovered Saturn’s rings in 1655 and invented the pendulum clock in 1656. He also discovered the mathematical formula for centripetal force. Second, I learned about calculus. Calculus is the mathematical study of change. It explains music and motion and can be used in calculators and computers. Third, I learned about Anton Van Leeuwhoek. He is known for microscopic discoveries and he made his own microscopes. Google recognized his 384th birthday in front of millions of people on October 24, 2016. Last, I learned about Isaac Newton. He studied natural philosophy in college in 1665. Newton’s work revolutionized science and helped us put men on the moon. He discovered laws of motion, gravity, and also classical mechanics from motion.