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Atoms that have the same atomic number, but different mass numbers due to the number of neutrons.

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Hair Detective

Hair Detective

Credit: Wicker Paradise
Source: http://www.flickr.com/photos/76061588@N03/8596739229
License: CC BY-NC 3.0

What does your hair say about you? It may say far more than you realize! Would you believe that your hair can be analyzed to reveal where you’ve been?

Why It Matters

  • Scientists have developed a way to determine from a single strand of hair where a person has lived. The longer the hair is, the longer the period of time for which the hair provides a record.
  • The procedure is based on stable isotopes of the elements hydrogen and oxygen. There are different concentrations of these isotopes in different regions of the world. When people drink the water in a given region, the isotopes end up in their hair in the same concentrations.
  • Credit: zack Mccarthy
    Source: https://www.flickr.com/photos/zack-attack/348566185
    License: CC BY-NC 3.0

    Stable isotope analysis of the hair can also determine the type of food a person consumes [Figure2]

  • Watch this video to learn about the analysis of stable isotopes and what it can tell us: http://uvamagazine.org/features/article/the_hair_detective/#.UhJh2oXD-M8

Can You Apply It?

Read about using isotopes to analyze hair at the links below. Then answer the questions that follow.

  1. What are isotopes? What are some examples of common stable isotopes?
  2. How are isotope concentrations in materials measured?
  3. What factors affect the concentration of isotopes in water in different geographic areas?
  4. Where are the highest concentrations of the isotopes H-2 and O-18 found in the U.S.?
  5. What is hair? How quickly does hair grow?
  6. How do isotopes end up in hair? How long does it take after you consume isotopes until they end up in your hair?
  7. How is the isotope content of hair used to solve crimes?
  8. What other real-world uses does this type of isotope analysis have?

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Image Attributions

  1. [1]^ Credit: Wicker Paradise; Source: http://www.flickr.com/photos/76061588@N03/8596739229; License: CC BY-NC 3.0
  2. [2]^ Credit: zack Mccarthy; Source: https://www.flickr.com/photos/zack-attack/348566185; License: CC BY-NC 3.0

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