Floaters and Sinkers
Mercury is a very dense liquid; it is 13.6 times denser than water. It is also the only metal that exists as a liquid at room temperature.Copyright Idaho National Laboratory http://www.inel.gov/env-energyscience/mercury/about.shtm
Students are introduced to the important concept of density. The focus is on the more easily understood densities of solids, but students can also explore the densities of liquids and gases. Students devise methods to determine the densities of solid objects, including the method of water displacement to determine volumes of irregularly-shaped objects. By comparing densities of various solids to the density of water, and by considering the behavior of different solids when placed in water, students conclude that ordinarily, objects with densities greater than water sink, while those with densities less than water float. Density is an important material property for engineers to understand.
Density is an important property in many materials engineering applications. Students use engineering in this unit by designing boats to float with various amounts of weight.
- Students will be able to define density as the amount of mass per volume a material contains.
- Students will be able to calculate the densities of objects when given their masses and volumes.
- Students will be able to compare the densities of several common materials.
- Students will be able to explain that materials that are denser than water ordinarily sink, while those less dense than water will float.