I learned about two inventions this week and they are the astrolabe and the double entry bookkeeping. I also learned about two inventors named Luca Pacioli and Leonardo da Vinci. The first invention I learned about is the astrolabe. It was a two-handed instrument used to read angles above the horizon. It was combined with ancient star charts to figure out the latitude. The second invention I learned about is the double entry bookkeeping. It’s an accounting system in which each transaction is recorded twice. It helps keep everything balanced. The first inventor I learned about is named Luca Pacioli. Luca’s most famous book is a Practical Business Handbook. One of his biggest impacts was the spread of double entry accounting. The last artist I learned is named Leonardo da Vinci. He studied light mechanics and the human body. He was also an engineer. He drew designs for inventions and was an artist. He is mostly remembered for the Mona Lisa.