A Cool Glass of Water
Department of Education
University of Michigan—Flint
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.
- 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.
KeywordsDensity; heat transfer; energy transfer; heat radiation; conduction; convection; melting; floating; sinking; experimental design
Educational LevelHigh school, Undergraduate lower division
Type / MethodsDirected
Subject HeadingsScience (General) | Chemistry (General) | Physics |
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