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A Cool Glass of Water


Author(s)

Li-hsuan Yang
Department of Education
University of Michigan—Flint
lihsuan@umflint.edu

Abstract

Does an ice cube melt more quickly in salt water or in freshwater? The answer surprises the group of student science teachers portrayed in this case study. To explain the phenomenon they must figure out the interactions between two clusters of concepts: (1) density and its relationship to floating or sinking, and (2) three modes of heat or energy transfer due to a temperature difference (particularly conduction and convection, with an optional discussion of radiation). The case can be adapted for use in general education science courses or for introductory physics or chemistry courses.


Objectives

  • Give the definition of density as mass per unit volume.
  • Describe how density affects the floating or sinking behavior of an object or a fluid.
  • Understand that heat transfer resulting from temperature difference can take place in more than one way (conduction, convection, or radiation).
  • Describe the mechanisms of conduction and convection.

Keywords

Density; heat transfer; energy transfer; heat radiation; conduction; convection; melting; floating; sinking; experimental design

Topical Areas

N/A

Educational Level

High school, Undergraduate lower division

Format

PDF

Type / Methods

Directed

Language

English

Subject Headings

Science (General)  |   Chemistry (General)  |   Physics  |  


Date Posted

11/04/07

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