Radiation

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Radiation
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Radiation

• When you see or hear this word what do you think
  about? What do you think it means?
• Share your thoughts with me by writing on the
  post it what you think about when you see this
  word. Do not put your name on the post it.

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Radiation is all around us

• It comes from the Earth and from outer space.
• Many forms of radiation are invisible -- we can't
  feel it, see it, taste it, or smell it.
• Yet, it can be detected and measured when
  present.

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Everyday we are exposed to Radiation

• Called natural or background radiation.
• Natural radiation accounts for about half of our
  total annual exposure.
• Man-made sources mostly medical procedures make
  up the other 50.

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Natural or Background Radiation

• Radon, a radioactive gas from uranium found in
  soil dispersed in the air Today Show - Radon
  Gas
• Radioactive Potassium in our food and water
• Uranium, Radium, and Thorium in the Earth's
  crust
• And from Cosmic Rays and the Sun.

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Man-made radiation sources

• tobacco,
• television,
• medical x-rays,
• smoke detectors,
• lantern mantles,
• nuclear medicine,
• and building materials.

Click Image to calculate your radiation exposure
according to the American Nuclear Society.
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Measuring Radiation

• A Geiger counter has a negatively charged Cu tube
  with a positively charged wire running through it.

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Measuring Radiation

• The tube is filled with gas at low pressure.
• Radiation knocks electrons off the gas which are
  attracted to the wire producing a current.

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Measuring Radiation

• An amplifier strengthens the current producing a
  clicking sound or a flashing light.
• The number of clicks or flashes per second tell
  how strong the radiation is.

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Watch and Learn

• Everyday Radiation Clip
• Radon Radiation
• Facts About Radiation
• Interactive Sources of Radiation
• Show Geiger Counter Demos
• Whys Guy shows some everyday radioactive
  materials. 424 min
• Fiesta Ware Info

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But what is radiation?

• Radioactive materials are composed of atoms that
  are unstable.
• An unstable atom gives off its excess energy
  until it becomes stable.
• The energy emitted
• is radiation.

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Know this

• While there are several different forms of
  radiation, we're going to concentrate on just
  three that result from the decay of radioactive
  isotopes
• alpha,
• beta,
• gamma.

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Lets Review What You Already Know

• What are isotopes?
• Element that have the same number of protons, but
  a different number of neutrons. Chemist call
  isotopes Nuclide
• What are radioactive isotopes?
• Isotopes that are radioactive.

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Lets Review

• A radioactive isotope emits particles and energy.
• When the process occurs, the radioactive isotope
  goes through nuclear decay producing
• An entirely new element or
• Another isotope of same element

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Nuclear Radiation

• Nuclear radiation matter and energy released
  when a radioactive isotope decays

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What happens when an element undergoes
radioactive decay?

• During radioactive decay an unstable nuclei of an
  isotope emits particles and releases energy, to
  become a stable isotope.

NUCLEAR
To radiate means to give off
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Non Ionizing Radiation

• Radiation that has enough energy to move atoms in
  a molecule around or cause them to vibrate, but
  not enough to move electrons.
• We take advantage of the properties of
  non-ionizing radiation for common tasks
• microwave radiation telecommunications and
  heating food
• infrared radiation --infrared lamps to keep food
  warm in restaurants
• radio waves-- broadcasting

My electrons vibrate!
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Electromagnetic Radiation

• Energy given off by an atom due to an
  acceleration of the atoms electrons

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Ionizing Radiation

• Radiation that falls within the ionizing
  radiation" range has enough energy to remove
  tightly bound electrons from atoms, thus creating
  ions.
• This is the type of radiation that people usually
  think of as 'radiation.'
• We take advantage of its properties to generate
  electric power, to kill cancer cells, and in many
  manufacturing processes.

You make my electrons leave!
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Nuclear Radiation

• A release of energy and particles from the
  nucleus of an atom

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The energy of the radiation shown on the spectrum
below increases from left to right as the
frequency rises.

• Type of Radiation
• Effects
• Source

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Three types of Ionizing Radiation

1. Alpha Particles
2. Beta Particles
3. Gamma Rays

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Alpha Particles (think charged particle Helium)

• What is it? Helium Nucleus
• Energy Low Energy
• Speed Varies
• Range 5 m (15ft.) in air, can be stopped by
  paper or skin
• Shielding required None
• Biological Hazard None unless in large
  quantities- Least Harmful

• Atomic Changes
• Mass number (decrease) -4 (2p 2n)
• Atomic number -2 (protons)

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The emission of a helium nucleus 2 protons
and 2 neutrons
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Alpha Decay
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Alpha Decay
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Beta Particle (think electron and transmutation)

• What is it? High Speed Electron- A neutron splits
  into a proton and an electron
• Energy Varies
• Speed Varies
• Range 5 m in air, can be stopped by clothes or
  wood
• Shielding required moderate clothing
• Biological Hazard Superficial Skin injury

• Atomic Changes
• Mass number no change
• Atomic number 1 (protons)

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Beta Decay
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Beta Decay
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Beta Decay
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A neutron in the nucleus of the atom becomes a
proton and emits an electron. Note a neutron is
not made of a proton and an electron.
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Gamma Rays (think wave or high energy light)

• What is it? Electromagnetic Energy High Energy
  Radiation- NOT MADE of MATTER
• Energy Varies
• Speed Travels at the speed of Light
• Range 500 m in air, can be stopped by lead or
  many feet of concrete
• Shielding required dense material such as
  concrete, steel plate, earth
• Biological Hazard Dangerous to living things

• Atomic Changes
• No change
• A Gamma Ray (?) is produced

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Gamma Rays
No Atomic Changes
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Gamma Rays
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Dont worryunless your name is Bruce.
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Review
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Nuclear Radiation
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(No Transcript)
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• Alpha, Beta, and Gamma. Which objects can travel
  through video. 58 min

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Electromagnetic Spectrum
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Lets Practice
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Lets Practice
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Lets Practice
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Lets Practice
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Lets Practice
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Challenge with a partner

• Use Atomic notation like the problems from the
  previous slides and create an alpha decay with
  the nuclide (isotope) of your choice

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Challenge with a partner

• Use Atomic notation like the problems from the
  previous slides and create an beta decay with the
  nuclide (isotope) of your choice

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