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How Can We Find Out What Is in Water?

Author(s): Nancy P. Moreno, PhD, Barbara Z. Tharp, MS, and Judith Dresden, MS.

The Science of Chromatography

The technique known as chromatography takes advantage of water’s “sticky” qualities, which enable it to travel up a piece of filter paper. When this happens, water molecules are attracted to charged regions on the cellulose molecules in the paper. As water moves up, it carries other molecules with it (such as the food coloring dyes used in this activity). Molecules found in different colors of food dye will move up the paper at different rates, based on their sizes and their level of attraction to the molecules of water. As a result, each food coloring dye will form a separate band or spot on the filter paper, ultimately creating a pattern. 


Funded by the following grant(s)

National Institute of Environmental Health Sciences, NIH

National Institute of Environmental Health Sciences, NIH

The Environment as a Context for Opportunities in Schools
Grant Numbers: 5R25ES010698, R25ES06932


Houston Endowment Inc.

Houston Endowment Inc.

Foundations for the Future: Capitalizing on Technology to Promote Equity, Access and Quality in Elementary Science Education