OVERVIEW:
Students will assume the roles of SREL environmental chemists as they work
to identify an unknown substance resulting from a mock accident and chemical
spill; i.e., a white powder leaking from a vehicle overturned on the Hwy.
278 bridge crossing Upper Three Runs Creek. Students will conduct physical
and chemical tests to identify the unknown substance after first conducting
tests on known substances. In the science seminar students will discuss how
they formed their conclusions.
TERMS
USED:
Process related—observation,
hypothesis, comparison, classification, prediction, independent variable,
dependent variable, inference, data
Content related—chemistry,
matter, states of matter, atom, molecule, mixture, compound, solid, liquid,
gas, subatomic particles, proton, neutron, electron, Periodic Table of Elements
OUTLINE
OF ACTIVITY:
This activity begins with a review of the last lesson and an introduction
to content in chemistry. This week’s featured SREL scientist is Dr.
Brian Jackson, who is an environmental chemist. The slide show introduction
will acquaint students with chemistry content, including atoms, elements,
atomic structure, molecular compounds, mixtures, and the Periodic Table of
Elements (i.e., material from Unit E, “The Building Blocks of Matter,”
in the science text book). This intro will conclude with a few illustrations
of how Brian, an SREL chemist, uses physical and chemical tests to determine
unknown compounds in samples that he analyzes.
Students will then break out into groups of four to conduct their own chemical analyses of four known substances and an unknown substance from the “spill.” The scenario for the exercise will be that they are acting as student investigators for a HazMat drill. After some demonstrations of various chemical tests, students will follow instructions to analyze their samples for physical properties and chemical reactivity. When necessary students will share their data with the entire group so that everyone has a complete data sheet.
During “science
seminar” closure we will discuss the results, and attempt to identify
to unknown substance by comparing test results to those from analyses of known
substances.
