Marie Curie (1867- 1934), a French and Polish scientist, studied radioactive phenomena and found two radioactive elements, radium and polonium, and won the Nobel Prize twice in her life.
Madame Curie and the Discovery of Radium
Maria Skoro Dovskaya, a famous Madame Curie, is known as "the mother of radium". She was born on10.7 in Warsaw, the capital of Poland, under the rule of Russian czar invaders. Her father is a physics professor at Warsaw University, which made her interested in scientific experiments since she was a child.
189 1 year, she went to Paris for further study and obtained two master's degrees. After finishing her studies, she planned to return to the motherland to serve the enslaved Polish people, but her acquaintance with the young French physicist pierre curie changed her plan. 1895, she married Pierre. 1897, she gave birth to a daughter, a future Nobel Prize winner.
Madame Curie noticed the research work of French physicist becquerel. Since Roentgen discovered X-ray, becquerel discovered another kind of "uranium ray" when he was checking a rare mineral "uranium salt", which his friends called Becquerel ray.
The ray discovered by Bekkerel aroused great interest of Madame Curie. Where does the energy of radiation come from? Madame Curie saw that no one in all laboratories in Europe had studied uranium rays in depth at that time, so she decided to enter this field.
At Pierre's repeated requests, the headmaster of the physics and chemistry school allowed Madame Curie to use a damp hut for physics and chemistry experiments. At the room temperature of 6 degrees Celsius, she devoted herself to the study of uranium salts.
Madame Curie received a strict advanced chemistry education. When studying uranium salt ore, she thinks there is no reason to prove that uranium is the only chemical element that can emit radiation. She determined the elements one by one according to Mendeleev's periodic law of elements. As a result, she soon discovered that another thorium compound can automatically emit rays, which are similar to uranium rays and have similar intensity. Madame Curie realized that this phenomenon is not just the characteristics of uranium, and it must be given a new name. Madame Curie called it "radioactivity", and uranium, thorium and other substances with this special "radioactivity" function were called "radioactive elements".
One day, Madame Curie thought, are minerals radioactive? With Pierre's help, she identified all the minerals that could be collected in a few days. She found that pitchblende was much more radioactive than expected.
After careful study, Madame Curie had to admit that the contents of uranium and thorium in these pitchblende can never explain the radioactivity she observed.
Where did this unusually high radioactivity come from? There is only one explanation: these bituminous minerals contain a small amount of new elements that are more radioactive than uranium and thorium. Madame Curie has checked all the known elements in her previous experiments. Madame Curie concluded that this is a new element that humans have not yet known, and she wants to find it!
Madame Curie's discovery caught Pierre's attention, and the Curies marched into the unknown elements together. In the damp studio, through the joint efforts of the Curie couple, in July 1898, they announced the discovery of this new element, which is 400 times more radioactive than pure uranium. To commemorate Madame Curie's motherland-Poland, the new element was named polonium (meaning Poland).
1898 to 65438+February, the Curies announced the discovery of a second radioactive element, which is more radioactive than polonium. They named this new element "Radium". However, at that time, no one could confirm their discovery, because according to the tradition of chemistry, when a scientist announces the discovery of a new element, he must get the physical object and accurately determine its atomic weight. However, in Madame Curie's report, there are no atomic weights of needles and radium, and there are no samples of radium at hand.
The Curies decided to prove it with real objects. At that time, pitchblende containing polonium and radium was a very expensive mineral, mainly produced in the San Joachimstahl mine in Bohemia. People refine this mineral and extract uranium salts to make colored glass. For the poor Curie couple, how can they afford the necessary expenses for this job? Their wisdom constitutes financial resources. They predict that after uranium is extracted, new radioactive elements contained in minerals will definitely still exist, so they can be found in mineral residues after uranium salt extraction. After many twists and turns, the Austrian government decided to give the Curie couple a ton of slag, and promised that if they needed a lot of slag in the future, they could supply it on the most favorable terms.
The laboratory conditions of the Curies are extremely poor. In summer, because the ceiling is glass, it is sunburned like an oven. In winter, people are freezing with cold. The Curies overcame unimaginable difficulties and tried to extract radium. Madame Curie immediately threw herself into the extraction experiment. She melted more than 20 kilograms of waste residue in a smelting pot, stirred the boiling substance with a thick iron bar for several hours, and then extracted only one millionth of trace substances from it.
They work from 1898 to 1902. After tens of thousands of times of refining, they treated dozens of tons of ore residue and finally got 0.l gram of radium salt, whose atomic weight was determined to be 225.
Radium was born!
The Curie couple confirmed the existence of radium, which made the whole world pay attention to the radioactive phenomenon. The discovery of radium triggered a real revolution in the scientific community.
Madame Curie finished her doctoral thesis entitled (Research on Radioactive Substances). 1903, Madame Curie received a doctorate in physics from the University of Paris. In the same year, the Curies and becquerel jointly won the Nobel Prize in Physics.
After the discovery of radium, other new radioactive elements, such as actinium, have been discovered one after another. Exploring the law of radioactive phenomena and the nature of radioactivity has become the primary research topic in the scientific community.