Activity 5: Density

One of the most common attributes of chemical materials that we observe and feel on a daily basis is the density of materials. One of the things we notice in the structures of atoms, is that the atom is mostly space, with a small heavy nucleus and very light electrons orbiting the nucleus. So, how heavy something feels is related to how many protons and neutrons are in the nucleus of atoms that make up molecules. For example, aluminum is much lighter than iron. The "heaviness" of a material is quantified through a characteristic called density.

Simulations and gaming aid in our understanding of chemical principles that I used to complete the following, will be found at this site: http://phet.colorado.edu/

1. Neutral lithium atom. P=3 N=3 E=3 

The density for a neutral lithium atom is: Melting Point: 180.54 °C (453.69 K, 356.972 °F)  Boiling Point: 1347.0 °C (1620.15 K, 2456.6 °F)

    A neutral boron atom:  P=5  N=6  E=5

The density for a neutral boron atom is:

Melting Point: 2348 K (2075°C or 3767°F)
Boiling Point: 4273 K (4000°C or 7232°F)
Density: 2.37 grams per cubic centimeter

2. According to the text, Chemistry for changing times(Hill & Kolb), the definition for density is, the quantity of mass per unit volume; otherwise written as:


3. Teaching Ideas:  Energy Skate Park  http://phet.colorado.edu/en/simulation/energy-skate-park

4. Mystery Block Density Simulation Data

	Mass	Volume	Density
Wood	2.05	5.12	0.40kg/L
Ice	4.71	5.12	0.92kg/L
Brick	10.25	5.12	2.00kg/L
Aluminum	13.84	5.12	2.70kg/L

5. Science Standards that could be met through the above activities are: 
Content Standard Science A: Students in Wisconsin will understand that there are unifying themes: systems, order, organization, and interactions; evidence, models, and explanations; constancy, change, and measurement; evolution, equilibrium, and energy; form and function among scientific disciplines.

Content Standard Science B, Nature of Science: Students in Wisconsin will understand that science is ongoing and inventive, and that scientific understandings have changed over time as new evidence is found.
Rationale
Students will realize that scientific knowledge is developed from the activities of scientists and others who work to find the best possible explanations of the natural world. Researchers and those who are involved in science follow a generally accepted set of rules to produce scientific knowledge that others can confirm with experimental evidence. This knowledge is public, replicable, and undergoing revision and refinement based on new experiments and data.

Content Standard C, Science Inquiry: Students in Wisconsin will investigate questions using scientific methods and tools, revise their personal understanding to accommodate knowledge, and communicate these understandings to others.
Rationale
Students should experience science in a form that engages them in actively constructing ideas and explanations and enhances their opportunities to develop the skills of doing science. Such inquiry (problem solving) should include questioning, forming hypotheses, collecting and analyzing data, reaching conclusions and evaluating results, and communicating procedures and findings to others.

Including:  Content Standard D (Physical), Content Standard Science, G (Applications),Content Standard H (Personal and Social Perspectives).