Name That Metal!
Given an assortment of unknown metals to identify, student pairs consider what unique intrinsic (aka intensive) metal properties (such as density, viscosity, boiling or melting point) could be tested. For the provided activity materials (copper, aluminum, zinc, iron or brass), density is the only property that can be measured so groups experimentally determine the density of the "mystery" metal objects. They devise an experimental procedure to measure mass and volume in order to calculate density. They calculate average density of all the pieces (also via the graphing method if computer tools area available). Then students analyze their own data compared to class data and perform error analysis. Through this inquiry-based activity, students design their own experiments, thus experiencing scientific investigation and experimentation first hand. A provided PowerPoint® file and information sheet helps to introduce the five metals, including information on their history, properties and uses.
Assorted metals: copper, brass, silver, germanium.Copyright 2010 Mauro Cateb, Wikimedia Commons http://commons.wikimedia.org/wiki/File:Metals_for_jewellery.jpg
Before designing and specifying materials to solve technical problems, engineers must have an understanding of the materials, including a familiarity with their properties. Density is one fundamental physical property. Across all fields—civil to biomedical to electrical engineering—engineers often develop their own procedures for testing materials so as to ensure a particular material fits the needs of a design. In this activity, students act as engineers to develop procedures for measuring a materials property and use that acquired knowledge to identify unknown materials.
After this activity, students should be able to:
- Utilize the scientific method to design experiments.
- Select an appropriate apparatus to measure an object's volume.
- Determine the density of an object.
- (optional) Use data to obtain density via graphical methods.
- Identify inconsistent results and sources of error.