Search
Showing results for “Radioactivity”
Jump to a topic
RadioactivityRadioactivity refers to the sudden ejection of particles from an unstable atomic nucleus. This instability arises from an imbalance in the forces holding protons and neutrons together at the center of an atom, leading to excess energy. By ejecting particles with this energy—a process called radioactive decay—the atomic nucleus becomes stabilized. These energetic particles comprise ionizing radiation, which, like gamma rays, X-rays, and high-energy UV light, can break chemical bonds and damage DNA.
The phenomenon was accidentally discovered by Henri Becquerel in 1896, when he noticed that uranium salts emitted radiation. Two years later, Marie and Pierre Curie coined the term "radioactivity" when studying similar radiation-emitting ores. After Ernest Rutherford and Frederick Soddy observed that radioactive thorium changed into radium, they theorized that radioactivity could transform one element into another. By 1903, Rutherford distinguished the three most common types of radioactive decay—alpha, beta, and gamma—and found that radioactive samples decay in a predictable, exponential way based on a value specific to the sample that he called half-life.
Subsequent research revealed the composition of these decay particles, alongside the existence of isotopes, protons, and neutrons. Collectively, these discoveries established the physics behind radiometric dating, nuclear power, and medical diagnostics and treatment, and more.Explore Radioactivity
What we've found
Learn about the applications of radioactivity in medical, academic, and industrial settingsBesides their use for radiometric dating by archaeologists and researchers at museums and universities, radioactive materials are used in sensors that help track ocean currents and analyze pollution, soil, and petroleum products. Radioisotope-based sensors also help measure air in ice cream and prevent spillovers when soda bottles are filled in factories. US Nuclear Regulatory CommissionA list of five everyday products that rely on radioactivity, including exit signs and gemstonesLike some glow-in-the-dark wristwatches, some exit signs contain sealed tubes of tritium—radioactive hydrogen gas—which emit low-energy beta particles that react with surrounding elements to produce light, making them visible without batteries. In smoke detectors, smoke particles disrupt the steady flow of ions generated by americium-241. US Department of EnergyDistinguishing between natural and artificial, or induced, radioactivityNaturally occurring radioactivity comes from radioactive elements underground, cosmic radiation from the sun and other objects in space, and radioactive atoms that make up the molecules we breathe, eat, and drink. Artificial radioactivity is predominantly generated for medical applications and industrial activities. European Nuclear SocietyWhy taking potassium iodide to protect against radioactivity is unlikely to be effectiveSince the thyroid gland cannot distinguish between radioactive and non-radioactive iodine, taking potassium iodide pills causes the thyroid to absorb the medication, leaving it unable to take up radioactive iodine from the environment. However, while this protects the sensitive gland against the most prominent radioisotope produced in nuclear accidents, it does not protect other body parts or shield against other radioactive substances. US Centers for Disease Control and PreventionWhere radon comes from and why it may be the most dangerous source of radioactivityReleased from underground bedrock before passing through soil, this radioactive gas is produced from the decay of uranium, thorium, and radium and accounts for about half of all human exposure to radiation. It is the leading cause of lung cancer among nonsmokers and can build up in enclosed spaces such as buildings without proper ventilation to dilute the gas. International Atomic Energy AgencyAn overview of radioactivity, which can spontaneously change one element into anotherUnstable atomic nuclei can transmute into a new element—an atom with a different number of protons—by emitting an alpha particle (two protons and two neutrons) or a beta particle (an electron). The electron can emerge from the nucleus when a neutron, which has no charge, suddenly transforms into a proton and an electron, thereby maintaining zero charge before and after the transformation, but altering the original element. TED-EdPaleontologists apply rules about rock layering, fossilization, and radioactivity to date geological samplesConcepts such as the understanding that older rock layers will form beneath newer ones allow scientists to compare the ages of samples from various layers. Although no geological site preserves evidence across all time, samples can be combined with fossils of known age, such as those dated by analyzing the decay of their radioactive isotopes, to reconstruct Earth's timeline. The Science of EverythingItems in the Curie Museum do not produce significant radioactivity todayIonizing radiation produced by elements such as uranium, polonium, and radium can damage living things, but the trace amounts found in the museum objects that Marie Curie once touched have been largely decontaminated, with more dangerous items stored in protective, lead-lined containers. SciShowMarie Curie's daughter Irene discovered artificial radioactivityThe discovery continued the family's Nobel legacy by winning the Nobel Prize in Chemistry in 1935 alongside her husband, Frederic Joliot. Their work laid the foundation for the use of radioisotopes in medicine, agriculture, and energy production. The ConversationHow the nuclear shell model explains the stability or radioactivity of atomic nucleiWhen the number of protons and neutrons completely fills shells within the nucleus, the binding energy that prevents these particles from being pulled apart increases. These are called "magic numbers," and they produce atoms with exceptionally stable nuclear configurations. SciShowThe Curies developed a way to measure radioactivity in an old medical dissecting roomDespite lacking proper laboratory conditions, Marie and Pierre built an ionization chamber and a piezoelectric quartz electrometer to measure the amount of charged particles released by radiation, with a sensitivity of ten-trillionth of an ampere. Substances with different emission rates indicated different elements. Google Arts & CultureRadioactivity was accidentally discovered when uranium left marks on photographic platesIn 1896, Henri Becquerel had been exploring phosphorescence—the emission of light of one color after an object is exposed to another color. He expected these emissions to come from objects exposed to sunlight, but he observed emissions after an overcast day. Scope TVPierre Curie's knowledge of electromagnetism helped decipher radioactivityAlongside his brother, he studied electric fields in crystals and the magnetic properties of substances, which required the construction of delicate electrometers. He would use this apparatus with Marie Curie to measure radioactive emissions and the presence of undiscovered radioactive elements. Nobel PrizeMarie Curie's research in radioactivity made her the first woman to win a Nobel PrizeOvercoming social and academic barriers, Curie's realization that radiation resulted from an intrinsic property of atoms reframed scientific understanding of the phenomenon. Her subsequent work in discovering two new elements—polonium and radium—earned her a second Nobel Prize. TED-EdMarie Curie pioneered radioactivity research, for which she won two Nobel PrizesMarie Curie and her husband isolated polonium and radium despite poor lab conditions and financial hardship. President Harding, on behalf of the women of America, presented her with one gram of radium in 1921 in recognition of her service to science. Nobel PrizeView the periodic table of radioactive elements, and a list of each's most stable isotopesTechnetium is the lightest artificial radioactive element, which is produced primarily as a byproduct of nuclear fission. Several unstable isotopes are commercially available to medical professionals and scientists, despite their radioactivity risks. ThoughtCoThe Gasbuggy Project detonated a nuclear bomb to fracture underground rock formationsPart of Project Plowshare—a program aimed at finding peaceful uses for nuclear devices—the 1967 experiment sought to extract natural gas trapped within shale in underground New Mexico. Gas radioactivity was found to be excessively high for use without expensive processing, and the project was deemed an economic failure. AAPGMore than 500,000 people worked to contain Chernobyl's falloutThe group—collectively referred to as "liquidators"—included firefighters, military troops, miners, engineers and sanitation crews. Beyond clearing radioactive debris and performing decontamination work, they confined radioactive material to prevent its spread into groundwater. Radioactivity.eu.comPolish chemist and physicist Marie Curie (1867–1934) on learning“Nothing in life is to be feared; it is only to be understood. Now is the time to understand more, so that we may fear less." Good ReadsHeat slowly moves through Earth's mantle like softened waxEnergy trapped during Earth's formation and released via the radioactivity of elements is carried by convection currents towards the surface, while cooler, denser material sinks. The planet's core is almost as hot as the sun's surface. MinuteEarthMisleading measurements and fear-based reporting often exaggerate radiation risksDaily exposure to radioactivity is common but occurs in low doses outside of locations near nuclear accidents like Chernobyl and Fukushima. Researchers have detected radiation in tuna, bananas, and the human body due to increasing instrumental sensitivity, not rising concentrations. FermilabThe Curies were buried in lead-lined coffins to contain their radioactive bodiesTheir discoveries of polonium and radium involved ongoing exposure to radioactive materials before shielding technology was developed. Their notebooks, furniture, and other belongings remain radioactive today, requiring researchers to sign a waiver and wear protective clothing to access. IFLScienceMarie Curie's work with radioactive materials left traces on her furniture and notesSome of Marie Curie's family heirlooms were radioactive and destroyed. Marie and Pierre Curie are entombed in lead coffins to block radiation. BBC
Try another search?