How to Identify Unknown Substances Using Properties

Crash Course Kids

In this engaging episode of Crash Course Kids, host Sabrina Cruz explores how physical properties can be used to identify unknown substances. Starting with a relatable scenario about choosing candy from a gift bag without looking, the video introduces the scientific definition of 'properties' and explains how scientists use observable traits to categorize matter. It defines key terms like 'substance' and 'element' while reviewing properties of common groups like metals (shiny, conductive, magnetic) and gases (shapeless, transparent). The video transitions into a practical 'investigation' segment that demonstrates how to distinguish between similar-looking substances. It first tackles two white powders (sugar and sand) by testing their solubility in water, emphasizing the critical safety rule of 'No Tasting.' Then, using a blindfold challenge, it distinguishes between a metal nail and a gummy frog based on hardness, flexibility (malleability), and magnetism. This hands-on approach models scientific inquiry and deductive reasoning. Ideally suited for upper elementary science classrooms, this video provides a solid foundation for units on matter. It connects abstract definitions to concrete examples and simple experiments that can be replicated in class. Teachers can use this resource to introduce the concept of characteristic properties, teach laboratory safety, or kick off a mystery substance lab activity where students must identify materials using only physical tests.