The Case of the Missing Crown
Barbara A. Johnson
Density is a property of matter which allows us to identify the substance that makes up that matter. The density of an object can be calculated by dividing the mass (g) of a substance by its volume (cm3). The density of a particular kind of matter is a specific property that helps identify it. By referring to a density chart, a person can determine the identity of a substance.
In this activity imagine that you are living in Europe in the Middle Ages. You have been summoned by the king of your land to help in a very important matter. Someone has stolen the king's solid gold crown. The king has issued a proclamation offering a reward of 500 gold coins for the safe return of his crown. The problem is that the king has received 5 crowns that appear to be made of pure gold and are identical to the missing crown. Your job is to correctly identify the gold crown, and persuade the King why your identification is scientifically accurate.
2. Complete the *chart that organizes the following data about the 5 crowns: all of the crowns are identical and have a volume of 180 cm3. The 5 crowns have the following different masses: 1890 g, 486 g, 1404 g, 3474 g, and 2034 g.
3. Calculate the density for each crown using the formula: Density equals mass divided by volume. Record the density for each crown in the chart.
4. Be certain that your chart contains complete headings for each column. Include the unit of measurement for mass, volume, and density.
5. Examine the chart "Density of Common Substances."
6. Use R.A.R.E. to answer the *questions to help clarify your thinking.
7. Summarize your findings in a paragraph persuading the king that you have correctly identified the real gold crown using scientifically accurate information. Before you begin to write, use a *graphic organizer to order your ideas in a logical way. Be certain to use supporting evidence from your density calculations and the table "Density of Common Substances."
Credits & References
Prentice Hall Matter: Building Blocks of the Universe, New Jersey 1997.
Organizer for Persuasive Essay From Inspiration 6.0