• Question: what is radio activity?

    Asked by howtaunk1 to Adam, Catherine, Karen, Leila, Nazim on 15 Mar 2012.
    • Photo: Leila Battison

      Leila Battison answered on 15 Mar 2012:

      Radioactivity is what you get when an unstable atom breaks down. It can come as a wave or a particle, and can damage your DNA if it gets into your body.

      Some elements, like uranium or potassium, can get quite big and have too many neutrons in their nucleus, making them unstable. They might break apart, or a few neutrons and protons might break off, making radioactivity. This is what is used in nuclear reactors to make energy, but it can eb dangerous if you are exposed to it for a long time.

    • Photo: Adam Stevens

      Adam Stevens answered on 15 Mar 2012:

      Some atoms are unstable. This can either be because they’re so totally an absolutely massive, or because they have too many protons /or/ neutrons (an equal amount is just about best), or actually if they’re just really excited.

      If an atom is too big (like Uranium-238, which has 238 protons and neutrons) it will shoot off an alpha particle, which is 2 neutrons and 2 protons, to lose some of this mass.

      If the atom has either too many protons or two many neutrons what happens is that it tries to turn one into the other to make them even. This gives off a beta particle, which can be either an electron, or the antimatter version of an electron (a positron). It also gives off a neutrino. An example of this would be Sodium-22, which wants to turn a proton into a neutron, leaving you with Neon-22.

      If the atom is just excited (it has too much energy) it wants to get rid of some of that energy, so it will give off a gamma ray. This normally happens at the same time as another type of decay like alpha and beta.

      Most radioactive substances, like Uranium, tend to give off lots of different kinds of radiation, making themselves more and more stable until they’ve decayed all the way to something like Lead, which is really stable.

      “Radioactivity” is the property the substance that means it will give off one of these types of radiation.

    • Photo: Karen Masters

      Karen Masters answered on 18 Mar 2012:

      It’s the name we give for atoms which are unstable and break apart. When they do this they can give off different kinds of particles which can be dangerous to humans. They were called alpha, beta and gamma particles (A, B, C in Greek alphabet), and we now know they are helium nuclei, electrons, and very high frequency photons (light).

    • Photo: Nazim Bharmal

      Nazim Bharmal answered on 21 Mar 2012:

      Essentially, some elements can become more stable by breaking up (slightly). In doing this, they release energy as either tiny bits (alpha and beta radiation) or as gamma photons (gamma radiation). All these types of radiation from elements breaking down are called radioactivity.

      The name comes from two Latin words: radius, meaning beam of light (because early experiment were done with photographic paper and seeing where the radiation landed on the paper) and active, which means the same in English.

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