Why is radioactivity important

The main negative health effect that people often associate with radiation exposure is cancer. Whilst many believe that all it takes is a single exposure to radiation for cancer to develop, this is not true.

Because we are constantly surrounded by radiation, our bodies have developed sophisticated protection mechanisms against its effects.

The health impacts of radiation is well understood and studied. The relationship between radiation exposure and cancer has been researched extensively for more than years and it has been proven that radiation is only a weak carcinogen — in other words, it takes a very large amount of radiation to increase the risk of cancer only slightly. Exposure to radiation is the principal public concern in the event of a nuclear accident.

The worst nuclear accident in history, which took place at Chernobyl, caused the death of 28 nuclear plant and emergency workers who were exposed to lethal amounts of radiation. Many of them received doses above 10 Sievert 10, mSv within minutes or hours.

Since the accident in , Chernobyl also resulted in about thyroid cases — which would have been prevented if the authorities had stopped contaminated foodstuffs from entering the food chain.

These cases have, to date, resulted in 15 deaths. In comparison, air pollution from the use of coal kills about 80 people - every hour - in China alone. Neither of the accidents at Three Mile Island nor Fukushima Daiichi — the only other civil nuclear power plants that have suffered accidents resulting in a noteworthy release of radioactive material into the environment — resulted in any radiation-induced health effects. Every year, nuclear medicine helps doctors diagnose and treat tens of millions of people.

Radiation can also be used as a non-invasive alternative to brain surgery. Many artificial sources add to this, including medical procedures such as X-rays, smoke detectors, building materials and combustible fuels. In very high doses, radiation can cause sickness and death within hours. The effects of radioactivity have been felt on an even grander scale with the meltdown of nuclear power plants throughout history.

The heat is used to boil water and create steam, turning a turbine and generating electricity. Another radioactive process could provide a safe way to generate clean energy: fusion. In contrast to fission, fusion involves joining two atomic nuclei together. Becquerel died 12 years after his initial discovery at age 54, with burns and scars likely from handling radioactive materials, and Marie Curie died several decades later from leukemia.

Today our greater understanding of radioactivity allows us to use it much more safely. Accidents with radioactive materials have decreased in frequency and produce fewer fatalities due to stringent safety measures and thorough emergency responses. Originally published by Cosmos as What is radioactivity? Lauren Fuge is a science journalist at Cosmos. Cosmos is published by The Royal Institution of Australia, a charity dedicated to connecting people with the world of science.

Financial contributions, however big or small, help us provide access to trusted science information at a time when the world needs it most. Please support us by making a donation or purchasing a subscription today. Share Tweet. Instead, the probability of an atom disintegrating is constant, as if unstable nuclei continuously participate in a sort of lottery, with random drawings to decide which atom will next emit radiation and disintegrate to a more stable state.

The time it takes for half of the atoms in a given mass to "win the lottery"--that is, emit radiation and change to a more stable state--is called the half-life. Half-lives vary greatly among types of atoms, from less than a second to billions of years. For example, it will take about 4. Iodine , commonly used in medicine, has a half-life of only eight days. What is a radioactive decay chain? Stability may be achieved in a single decay, or a nucleus may decay through a series of states before it reaches a truly stable configuration, a bit like a Slinky toy stepping down a set of stairs.

Each state or step will have its own unique characteristics of half-life and type of radiation to be emitted as the move is made to the next state. Much scientific effort has been devoted to unraveling these decay chains, not only to achieve a basic understanding of nature, but also to design nuclear weapons and nuclear reactors.

The unusually complicated decay of uranium , for example--the primary source of natural radioactivity on earth--proceeds as follows: [88] U emits an alpha Thorium emits a beta Protactinium emits a beta Uranium emits an alpha Thorium emits an alpha Radium emits an alpha Radon emits an alpha Polonium emits an alpha Lead emits a beta Bismuth emits a beta Polonium emits an alpha Lead emits a beta Bismuth emits a beta Polonium emits an alpha Lead , which is stable How can radioactivity be caused artificially?

Radioactivity can occur both naturally and through human intervention. An example of artificially induced radioactivity is neutron activation.