How Can We Find Out What Is in Water?
Small amounts of many different substances can be dissolved in water at the same time. Many of these substances are not visible or distinguishable when mixed together in water. In this activity, students will use a simple separation technique to detect the presence of several different food dyes in water.
Ask students if they are able to identify all the food colors used to create the liquid in the photo. Now, show students the mystery liquid. Ask them, Can you tell what is in this liquid?
Explain that each student is going to become a detective and investigate the contents of the mystery liquid.
- Moreno N., and B. Tharp. (2011). The Science of Water Teacher’s Guide. Third edition. Baylor College of Medicine. ISBN: 978-1-888997-61-3.
- Photo montage adapted from two images: "The Face Within" and "Fun With Food Coloring" © Sean McGrath, CC-BY-SA 2.0.
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Funded by the following grant(s)
The Environment as a Context for Opportunities in Schools
Grant Numbers: 5R25ES010698, R25ES06932
Foundations for the Future: Capitalizing on Technology to Promote Equity, Access and Quality in Elementary Science Education