Distinguishing between natural and artificial, or induced, radioactivity

Learn about the applications of radioactivity in medical, academic, and industrial settings

Besides 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.

Where radon comes from and why it may be the most dangerous source of radioactivity

Released 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.

A list of five everyday products that rely on radioactivity, including exit signs and gemstones

Like 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.

An overview of radioactivity, which can spontaneously change one element into another

Unstable 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.

Astatine-211 is a radioisotope that can be used for therapeutic cancer treatment

With less than 30 grams in the Earth's crust at any given time, astatine is the rarest naturally occurring element. Its decay produces alpha particles that can damage diseased cells with the same impact as 10,000 electrons.

Radioactive elements can introduce software errors because the ionizing radiation they produce can detach electrons from atoms, and computer code relies on the distribution of electrons.

Misleading measurements and fear-based reporting often exaggerate radiation risks

Daily 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.

Radioactivity was accidentally discovered when uranium left marks on photographic plates

In 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.

Uranium's ability to split easily makes it the most common catalyst for nuclear power

Uranium is commonly found in rocks, water, and soil worldwide, but significant industrial processes are needed to process and enrich it for efficient reactor usage. After being irradiated in reactors, it must be cooled down before disposal.

Marie Curie's daughter Irene discovered artificial radioactivity

The 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.

An overview of helium, the nonrenewable resource that's lighter than air

The second element in the periodic table naturally forms deep underground over the course of billions of years through the decay of radioactive elements, but it is used and lost to space at rates faster than it is generated. Because of this and its extensive applications in scientific technologies, scientists continue to seek avenues for its exploration, storage, and recycling.

Cosmic rays are high-energy particles from outside the solar system

Trillions of these particles moving close to the speed of light hit Earth daily, with some originating from beyond our galaxy. While the planet’s magnetic field blocks most, some collide with atoms in the atmosphere, producing cascades of exotic secondary particles.

Meet the Earth's 'radiation donuts'

Radiation donuts might summon up a certain television cartoon character's favorite snack, but they're something else entirely. Also known as Van Allen belts, these zones of radiation arise from charged particles emitted from the sun and subsequently captured by the Earth's magnetic field. Understanding the underlying physics of the Van Allen belts is critical to modern-day telecommunications.

How radio works

Antennae tune a radio to a particular frequency (determined by the listener on their radio's dial) while tuning out all the other stations being broadcast. AM, short for amplitude modulation, and FM, short for frequency modulation, decode audio signals differently, leading to differences in sound quality and the distance a station can travel.

More than 90% of the atoms in the human body were forged by stars

Excluding all of the universe's hydrogen and most of its helium and lithium that formed in the Big Bang, elements found in significant amounts in our bodies formed through nuclear fusion within stars, collisions between neutron stars, or stars undergoing supernova. For example, all of the oxygen (65% of our mass) came from massive stars exploding.

Metal detectors identify induced magnetic fields in conductive objects

A changing magnetic field in a transmitter coil causes an electric current to be produced in materials that conduct electricity. This current generates its own magnetic field, which can be detected by a receiver coil and transmitted to a control box, which identifies the presence and depth of an object.

Volcanic activity can lead to the formation of fertile soils

Ejected rock can introduce key minerals found in fertilizers, including iron, magnesium, and potassium, to improve soil quality. Ash and basalt crystals can be easily absorbed into soils, infusing them with sulfur, oxygen, chlorine, phosphorus, calcium, and other critical elements.

Treatment-induced menopause is menopause induced by surgery or medicine

Chemotherapy and radiation, as well as oophorectomy (a surgical procedure that removes the ovaries) and a radical hysterectomy can cause a woman to become menopausal. Women that go through medical menopause experience the same symptoms as women that experience menopause caused by natural hormonal cycles.

Distinguishing between various solar surface phenomena, including solar flares and sunspots

Flares are sudden eruptions of electromagnetic radiation caused by a buildup of magnetic energy in the sun's atmosphere and often occur near sunspots, where strong magnetic fields limit the flow of hot material, creating these cooler regions. Flares can also be accompanied by coronal mass ejections—large explosions of plasma from the sun's upper atmosphere with their own magnetic fields.

While atoms are normally made of protons, neutrons, and electrons, exotic ones have been built with antimatter—alternate versions of normal matter that live for fractions of a second and are about a billion times as rare.

The highly contaminated Chernobyl region suffers from reduced biodiversity

Although isolation and radiation have driven adaptations in some organisms, decades of radiation have caused ongoing harm to wildlife and vegetation, including population declines in birds and insects. Higher rates of deformities and tumors have also been seen compared with animals in surrounding regions.

Demystifying the claim that crude oil is inorganically created and a renewable resource

The abiogenic petroleum theory holds that fossil fuels originate in Earth's mantle and are constantly replenished, rather than formed by microorganisms over millions of years. While inorganic chemical processes can produce simple hydrocarbons, the range of complex molecules found in crude oil suggests an origin from a diverse set of organisms. Isotope analyses of these molecules also support the model that they originated from living things that preferentially take up certain isotopes over others.

Proof of 'natural' food claims are voluntary for most food products

Unlike the enforcement done by the USDA for meat, dairy and eggs, the FDA offers loose guidelines for using a "natural" food label on most foods, and following the guidelines is voluntary. As a result, many products labeled as "natural" can contain processed ingredients and synthetic additives.

Spontaneous combustion involves an object igniting on its own

Even without matches, sparks, or external flames, exothermic chemical or biological reactions can increase the internal temperature of objects to the point where they reach a threshold temperature that can cause them to catch fire. Running batteries and fermenting bacteria within compressed materials can build this heat and cause combustion.

The history of natural and synthetic plastics

From cheap toys to woolly jumpers, plastic can be found in more products than many people realize. From a chemist's perspective all these things are made of the same class of materials: Polymers. And the distinction between which ones we happen to call "plastics" and which ones we don't is fairly arbitrary.

Some synthetic diamonds are purposely made with defects for new technologies

Grown in plasma-filled chambers or reactors where pressures reach 800,000 pounds per square inch, diamonds can develop properties like electrical conductivity and magnetic field sensitivity through exposure to elemental impurities or removal of some of their carbon atoms.

What is the rarest color in nature?

Plants, animals, or minerals found in nature bear almost every color imaginable. There are two factors that influence what hues you see in the wild: physics and evolution. So, which colors are you least likely to see in the natural world? Victoria Hwang explores one of nature’s rarest spectacles.

How fusion—which releases energy when two lighter atoms combine to form a heavier atom—differs from fission

Learn how your body is, scientifically, like a firework with its own slow, controlled burn.

Some Pokémon have been named after real and fictional organisms, while some real-world species have been named after Pokémon, such as Chilicola charizard and Binburrum zapdos.

Planeterrellas create artificial auroras that mimic the atmospheric displays of light by setting up an electric field between two metal balls in a jar filled with a small amount of air.

Sunflowers have long been a symbol of nuclear disarmament because they can extract large amounts of radioactive cesium from soil.

The history of many kitchen appliances involves unexpected discoveries and applications, including wartime radar turned hamster defroster and replacing an 'ice king' with heat-stealing boxes.

Louisiana's 'Cancer Alley' is infamous for having some of the highest industrial pollution, toxic air emissions, and cancer risks in the US.

The first line of 'immortal' human cells, which can divide indefinitely and are used in scientific research, was nonconsensually taken from a Black woman.

Volcanoes 'die' when their supply of magma runs out, if they are shifted away from their underlying magma reservoir, or if they get clogged by collapsing or their magma cooling back into rock.

Larger animals like giraffes, elephants, and blue whales have developed a unique defense against cancer, a phenomenon known as Peto's Paradox

Listen to an in-depth conversation on the links between Parkinson's disease and herbicide exposure and the challenging pace of scientific investigation.

Some renewable energy sources may weaken the resiliency of electric grids by removing outage buffers provided by coal- and natural gas-fired plants, which provide the system with more time to find a new power source if a plant goes down.

Poison ivy's rash-causing compound is found in the plant's roots, stem, and leaves—so coming into contact with any part of the plant can lead to rashes for the 85% of people who are allergic to it.

Human-to-human transmission of hantavirus remains extremely rare, so the 2026 hantavirus cruise ship outbreak doesn't mean we're facing a COVID-style pandemic risk.

Scientists can determine Earth's past climate conditions by analyzing air trapped in microscopic bubbles within ice cores—columns of compressed snow layers that build up over hundreds of thousands of years.

Pure water does not conduct electricity because this flow of energy requires the movement of charged particles, and water is a neutral molecule.

Most of the observable universe's volume consists of voids and supervoids—enormous regions of space with little to no galaxies, stars, or light.

This site reaches millions of visitors who are tired of AI chatbots and seeking human connection. Pretend to be an AI chatbot and ask questions, provide answers, and draw for people in real time.

Artificial coral reefs have been 3D printed from nontoxic, biodegradable terracotta clay, which coral polyps have used as a foundation for rebuilding marine ecosystems.

Doctors differentiate between a phobia and fear by asking patients whether their fear interferes with their day-to-day activities.

Long before Major League Baseball began allowing instant replay for balls and strikes, an umpire reluctantly used the technology to determine whether a hit was a home run, a move that inadvertently ushered in a new era for the sport.

Art theft is the third-largest source of criminal revenues worldwide, thanks in part to the subjective nature of valuing a work of art.

The Great Salt Lake's distinct dual coloration results from high-salinity organisms that only live in the northern portion and produce a purple protein.