Unit8 Lesson22 Famous Discoveries课件 2022-2023学年北师大版英语九年级全册

Unit 8 Lesson 22 Famous Discoveries www.515ppt.com 1 Antibiotics DNA X-rays www.515ppt.com 2 1.What discovery do you think is the most interesting one? I think X-rays are the most interesting discovery. Warm-up Example www.515ppt.com 3 Antibiotics DNA X-rays Wilhelm Roentgen , a German scientist , was the first to study and name X-rays in 1895 and in 1901,he was awarded the first-ever Nobel Prize in Physics for this discover . X-rays go right through some things , like skin and wood , but are stopped by others , such as bones or metal . This means that they can be used to see broken bones in people or things inside suitcases . With X-rays machines doctors can treat broken bones much more easily. Reading DNA is the building block of the life and was discovered in 1869.Over many years , scientists have slowly learned more and more about DNA . In 1928,scientists discovered that DNA passed on certain characteristics from parents to children . In 1953,the famous structure of DNA was discov