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pH Concept

Outlines how the acidity of water is measured and what makes solutions acidic or basic.

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Wet or Stinky

Wet or Stinky


Credit: Wilfredor
Source: http://commons.wikimedia.org/wiki/File:Boy_Face_from_Venezuela.jpg
License: CC BY-NC 3.0

Whether we call it perspiration or sweat, we all do it. Why do we sweat? It helps cool us down when we get overheated. But sweat can have an unpleasant odor, especially after puberty.

News You Can Use

  • That’s where underarm hygiene products come in. There are two basic types of products for dealing with stinky armpits: deodorants and antiperspirants. Both types were invented more than a century ago. Now, worldwide sales for these products exceed $18 billion a year!
  • Clearly, most people don’t want to stink, but they also know surprisingly little about the products they use to prevent it. Most people don’t even know whether they use a deodorant or an antiperspirant. 
  • Credit: Clean Wal-Mart
    Source: https://www.flickr.com/photos/cleanwalmart/427620751
    License: CC BY-NC 3.0

    There are many different types of deodorant for buyers to choose from [Figure2]

  • Watch this video to find out how deodorants and antiperspirants differ and when each should be used:


Can You Apply It?

Learn more about antiperspirants and deodorants at the links below. Then answer the questions that follow.

  1. Human sweat doesn’t stink. What causes stinky armpits?
  2. What do deodorants do? How do they do it?
  3. What do antiperspirants do? Describe how they work.
  4. Aluminum chloride forms in an acid-base neutralization reaction. The reactants in this reaction are aluminum hydroxide (AlOH) and hydrochloric acid (HCl). What are the products of this reaction? Why is the reaction called a neutralization reaction?
  5. The second article above describes an informal experiment. The author tested several different antiperspirants under different conditions. What types of sweat were investigated in the experiment?
  6. What were the manipulated variables in this experiment?
  7. What were the responding variables in the experiment? How were these variables measured?
  8. Describe some of the controls that were used in the experiment.

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Image Attributions

  1. [1]^ Credit: Wilfredor; Source: http://commons.wikimedia.org/wiki/File:Boy_Face_from_Venezuela.jpg; License: CC BY-NC 3.0
  2. [2]^ Credit: Clean Wal-Mart; Source: https://www.flickr.com/photos/cleanwalmart/427620751; License: CC BY-NC 3.0

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