University Libraries - Exhibitions

August – December 2011

The International Year of Chemistry 2011 (IYC 2011) is a worldwide celebration of the achievements of chemistry and its contributions to the well-being of humankind. Under the unifying theme “Chemistry—our life, our future,” IYC 2011 will offer a range of interactive, entertaining, and educational activities for all ages. The Year of Chemistry is intended to reach across the globe, with opportunities for public participation at the local, regional, and national level.

At the University of Iowa Libraries, an exhibit has been compiled emphasizing how fundamental chemistry is and how it can be seen in everyday life. The exhibit will be on display from July to December 2011.

Wherever we look, the work of the chemist has raised the level of our civilisation and has increased the productive capacity of the nation.
— John Calvin Coolidge

What is the molecular different between a diamond and a pencil?
Diamond and pencil lead (graphite) are both forms of the element carbon. Different pure forms of an element, like diamond and graphite, are called allotropes. In diamond the carbon atoms are arranged in a tetrahedral pattern, forming a very hard substance. In graphite the carbon atoms are arranged in sheets which slide easily over each other, making it suitable for use in pencils.

How Does Sunscreen Work?
Sunscreen works by combining organic and inorganic active ingredients. Inorganic ingredients like zinc oxide or titanium oxide reflect or scatter ultraviolet (UV) radiation. Organic ingredients like octyl methoxycinnamate (OMC) or oxybenzone absorb UV radiation, dissipating it as heat.

Why isn’t bread alcoholic?
Yeast works by consuming sugar and excreting carbon dioxide and alcohol as byproducts. In bread making, yeast is the product behind fermentation. The process that allows a dense mass of dough to become a well-risen loaf of bread. The alcohol produced is later burned off in the baking process.

What happens when Mentos and soda pop are combined?
Rough, dimply surfaces of Mentos encourage bubble growth because they efficiently disrupt the polar attractions between water molecules, creating bubble growth sites. The carbon dioxide in the soda has an affinity for the surface of the Mentos and sticks to it. Tiny bubbles start to form at such a fast rate that it forces a fountain to come out of the bottle. The flavoring in the soda affects the rate and size of the explosion. The more flavoring droplets, the faster the flow.

Acknowledgements

Exhibition Planning

Barbara Brodersen, Christopher Childs, Leo Clougherty, Kari Kozak

Production and Installation Assistance

Bill Voss

Graphic design

IMU Design and Marketing

Special thanks

University of Iowa Chemistry Department