Hello every one in this video I'm going to tell you about the most radioactive metal on Earth that is about Radium. This metal is about a million times more radioactive than Uranium, however let's first talk about the discovery of this metal, that is about Marie Skłodowska Curie and her husband; Pierre Curie and also about how their discovery of Radium affected their health and life Marie Curie’s career in science began in 1897 when she entered The City of Paris Industrial Physics and Chemistry Higher Educational Institution When working at the laboratory she came across very interesting results of
Henri Becquerel’s experiments with uranium. Becquerel noticed that the element emitted
mysterious glow which was not known as radiation yet. Marie Curie dedicated her doctoral dissertation to studying these strange invisible rays uranium emitted. Soon Marie’s
husband Pierre Curie joined her in this research. The first task these two scientists had was to somehow measure the amount of this strange radiation emitted by uranium and its ore, uranyl. which this metal extracted from. This is when Pierre Curie’s knowledge were of great help as earlier
he had discovered piezoelectricity. The first device for measuring radioactivity was
based of this discovery. First of all, you need to understand the principle of piezoelectricity. If you don't know what is that, it might surprise you that you observe this effect, everyday. when using piezo lighters. They have a special
mechanism which works using the electric charge, we can see as a streak of electricity in the electrode, produced as a result of applying pressure
to a piece of quartz with the help of igniter end cap. This effect can be observed not only in
quartz crystals, but also in other dielectrics, for instance in ceramic coatings of
piezoelectric speakers. If to solder a light emitting diode and to strike the ceramic, its deformation will cause an electric potential difference. which makes the light
emitting diode glow for a short time. Thanks to his discovery of the piezoelectric effect Pierre Curie assembled such a device for measuring radiation. There is a piece of pure monocrystalline quartz inside the piezo electrometer, but not the like the ones you see on the screen, rather in the shape of a cuboid. A small platform is attached to a piece of quartz fixed in a place. It is loaded with weights, stretching makes the crystal release its electrons, which pass to the capacitor through the electric chain. Thus different weights on the platform produce different electric pressure in the crystal which passes to the second part of the electrometer through the coaxial cable, which has a small mirror Increasing of the electric charge in the capacitor, slightly offsets the mirror, making the beam of light reflect along a certain line. In order to neutralize the charge and put the mirror back, the energy contained within the capacitor needs to be released somehow. That is why the last part of the device contains an ionization chamber where a radioactive material is put. Radioactive decay of heavy atoms produces charged particles, these particles hit the air molecules and create ions, which can conduct electricity and make the air around the radioactive material slightly conductive. Capacitor releases electrons and they can travel through the ionized air thus returning the beam of light back to the beginning of the line. Marie Curie held a watch in her hand, which measured how much time it would take for the radioactive specimen to ionize air in the chamber and to compensate the charge created by the piezoelectric material. By alternating weight and time periods you can measure the amount of charge created by a certain specimen. For instance a piece of pure metallic uranium produced charge of just 24 picoamperes, some uranium ores however, were much more radioactive than pure uranium. The Curie’s family assumed that there was something else more radioactive in the ore than uranium or thorium which had been discovered by that time. To confirm their assumptions of discovering a previously unknown element, Pierre and Marie Curie decided to buy with their own money a few hundred kilograms of uranium ore They chemically extracted the new element from the uranium ore. During 4 years Marie and Pierre Curie were purifying 7 tons of uranium ore in stock room of the university to extract the new precious metal from it which then they also purified. Chemical properties of the unknown highly radioactive metal were similar to those of barium. Its sulfate was also poorly soluble in water although its chloride dissolved well. The device invented by Pierre was showing higher and higher readings of radioactivity.
Finally, in 1902 the Curie’s family managed to obtain one tenth of gram of pure radium chloride and precisely calculate atomic mass of the newly discovered element. The newly discovered element radium is formed in the process of decay of naturally occuring uranium 238 and in contrast to other radionuclides it can accumulate in the ore, because it has the longest half-life, which is more than 1600 years. Just a year later the science community of Paris accepted the scientific discovery of Marie Curie with high regard and she received her first Nobel prize in physics the same year, which she couldn’t even get personally, because of her deteriorating health after four years of exposure to radiation that resulted from radium purification. Back then no one knew the terrible effects of radiation on health Up to this day many of Marie Curie belongings are highly radioactive because of having been contaminated by isotopes. According to Marie’s measurements radium turned out to be more than a million times more radioactive than uranium. This strong radiation even tarnished tools used for handling radium. Take a look at this desiccator.
After being awarded a Nobel prize and tragic death of her husband in a road accident Marie Curie was given her own laboratory where in 1910 she obtained pure metallic radium with the help of electrolysis of radium chloride. This metal looks a lot like barium. It is slightly more chemically active and also its compounds give burners’ flames bright red colour. Radium’s solutions and compounds glow blue in the dark because of radioluminescence. In 1911 Marie Curie was awarded another Nobel prize this time in chemistry for discovering radium and studying its properties. After discovering the element with an atomic number 88 people began to use it in medicine for radiotherapy treatment of cancerous tumors. Radium institute founded under Marie Curie’s supervision studied health benefits of the newly discovered element. Even back then it was known that cancerous tumors irradiated by radium chloride were more likely to heal. However, by 1920-th most people had got to know about radium’s curative properties and began to use in all possible ways. Its compounds were added to cigarettes, perfumes toothpastes. It was added to all sorts of products in attempts to cash in on common people. Those of you who have watched “Blade Runner 2049” probably remember the emanator the main character had. In reality though devices that were called emanators looked like siphons, which were used in 1920-th for enriching water with supposedly magic particles, which in reality were by products of radium 226 decay, for example the radiactive gas radon, which back then used to be called radium emanation. People used to drink such water and believe that it could cure them. Back in those days because of high demand for radium, its price skyrocketed and one gram of radium could cost up to 20 kilograms of pure gold which is about 1 million US dollars now. It will just suffice to mention the infamous radium self-luminous paint which had been used up until 1970-th. The thing is if radium chloride is combined with zinc sulfide, activated by silver, because of the alpha radiation radium emits, zinc sulfide starts glowing, this is how self-luminous paint of permanent action is produced. It can glow for years on end until zinc sulfide layer decays. Starting from 1920-th people began applying it to hands of clocks. This job was done by industrious women at numerous factories. For the sake of convenience the women pointed brushes on their lips to give them a fine point every time they applied it. Thus they constantly ingested radium compounds which later led to a huge scandal. Now old devices and clocks with radium self-luminous paint are considered extremely dangerous In the 20-th there even were sold kits with radium dust for making a Wilson cloud chamber for tracking alpha particles at home. Back in those days nobody knew of the dangers of radiation and especially that of radium on organism.
Nowadays radium is still used as a radioisotope medical treatment. Speaking of Marie Curie she fell victim to her own discovery. All the years of exposure to ionizing radiation took a toll on her health and she died at the age of 66 from leukemia. I am pretty much sure that it is a myth that she wore an ampoule with radium in her pocket or on her neck because it is extremely easy to get a painful radiation burn. I think she wasn’t so silly as to always have such a thing in her pocket. And finally, Marie Curie’s studying of the most radioactive element in nature gave science fresh impetus and propelled the world into the atomic 20-th century.
