The Many Uses of Radiation

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The Many Uses of Radiation
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Nuclear Power Plants

• 104 operating nuclear power plants in the U.S.
• 20 electricity in U.S.

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Medicine

• Sterilization of Medical Products
• New Drug Testing
• Diagnosis
• Cancer Therapy

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Nuclear Research in Cancer Therapy

• Boron neutron capture therapy
• Recent advances in killing malignant brain tumors
  (extensive work at Ohio State)
• Cell directed radiation therapy
• Direct injection into tumors
• Hyperactive Thyroid and Graves Disease control
  (I-131)

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Food and Agriculture

• Food irradiated
• Kill pathogens and extend shelf life
• Reduce Needs for Fertilizers and Water
• Speed Breeding of Improved Crops
• Greater yields
• Better nutritional value
• Increased disease resistance for
• development
• Insect Control

Co-60 food irradiator
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Public Safety, Crime Fighting, Science

• Fighting terrorism
• Lighting (airports, exit signs, traffic control)
• Homes (smoke detectors)
• Gun Powder Residue Analysis
• DNA Fingerprinting
• Art Counterfeiting
• Dating
• How old is the earth? How old is a bone sample?

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How do we tell how old something is??

• Is this painting real or a forgery??
• Scientists use radioactive elements to determine
  age!
• How? Radiometric Dating Half-Life!

Woman Reading Music
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How it Works Nuclear Decay

• When radioactive elements emit particles, they
  are no longer the same atom. For example, if an
  atom emits a proton, its atomic number has
  changed.
• Example A Potassium isotope loses a proton, so
  its atomic number changes from 19 to 18. It
  decays to become an Argon isotope.
• What type of decay is this?

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Rates of Decay

• How quickly/slowly do atoms lose particles (or
  decay)?
• Its different for each isotope.
• Half-life the amount of time required for half
  of a radioactive substance to decay.
• When we say DECAY, do we mean that the substance
  rots or goes away? What do we mean?
• The substance CHANGES into new atoms.

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Decay Rates

• Tennis player original radioactive substance
  (aka parent)
• Little girl CHANGED/NEW atoms (aka daughter)
• Remember, half-life is the amount of TIME
  required for HALF of the substance to DECAY or
  CHANGE.

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Lets Take A Closer Look
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Explanation

• So with each half-life, enough time passes that
  HALF of the TENNIS player CHANGES INTO a LITTLE
  GIRL.

• When another half-life passes, HALF of the
  REMAINING TENNIS player CHANGES INTO more LITTLE
  GIRL.
• So the tennis player is decaying, but she is not
  going away. She is merely CHANGING into
  something else.

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Half-life Calculations

• The half-life of Iodine-131 is 8 days. If you
  start with 50 grams, how much Iodine will be left
  after 8 days?
• Half of it! 25 grams
• How much Iodine after 16 days?
• 2 half liveshalf of 25 12.5 grams
• After 24 days?
• 3 half liveshalf of 12.5 6.25 grams
• How many half-lives have passed after 24 days?
• THREE!!

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Real or Forgery??

• Back to the paintingis it real or a forgery?
• The real Woman Reading Music was painted in
  1663.
• This painting dated as being painted in 1935.
• A FORGERY!!

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Practice Question

• What color represents the original radioactive
  substance?
• RED
• What color represents the NEW substance?
• BLUE

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Another Practice Question

• C-14 decays to N-14.
• Scientists know how much C-14 is present in the
  air.
• They compare this number to the amount in
  something dead.
• Used to determine how long a living thing has
  been dead!!

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Carbon-Dating in Forensics

• C-14 has a half-life of 5,715 years.
• You find a body that has 500 g of C-14 left.
  You know this body had 1000 g of C-14 when he/she
  died because the air has that amount of C-14.
  How long has this person been dead?
• 5,715 years!
• Lab time - Now its your chance to figure out who
  died!

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And NowThe Atomic Bomb

• Why did it cause so much damage?
• Lets look at some historical pictures of the
  bomb.

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Atomic Bomb Pictures

• Noriaki Teshima (male) 12 year old junior high
  school student
• He was exposed to the bomb at school. He
  suffered major burn over his entire body, to the
  extent that his skin was dangling in tatters.
  With the help of a friend he returned home.
  Suffering from terrible thirst, he is said to
  have tried to suck the puss from his raw,
  nail-less fingers. He died in agony on August 7,
  1945. His mother kept his fingernails and part
  of his skin to show his father, who had not
  returned from the war.

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The next picture shows floor tiles that were
melted from the heat.
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Black Rain

• After the bombing, violent fires raged through
  the city, whipped up by whirling winds. Soon,
  heavy rain fell Northwest of downtown.
• For the first hour or two, the rain fell in huge
  black drops, discolored by mud and soot.
• This black rain contained highly radioactive
  materials that killed fish in the rivers.
• People who drank well water in the affected areas
  suffered from severe diarrhea for up to three
  months.

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No One Survived.

• Anyone in the general area of the atomic bomb
  drop was killed, either slowly or instantly.
• The following picture is an artists rendition of
  what the civilians might have looked like
  immediately after the bomb drop.
• Look closely and youll notice their skin
  dripping off.

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