The Density Dilemma:
The Case of the Missing Crown
A WebQuest for 8th Grade Earth Science
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 Syracuse in the Bronze Age, circa 250 BC (2,259 years ago!). You have been summoned by the king of your land, His Majesty Hiero II, to help in a very important matter. King Hiero has commissioned some goldsmiths to make for him a wreath crown of pure gold. Five goldsmiths brought to him five identical crowns. Hiero has hired you because he has heard rumors that only one of the five crowns is in fact pure gold! The other four might have been made of different metals! It is up to you to scientifically find which crown is the pure gold crown. Since the crown is a holy object you are not to disturb it in any way. How will you do it? Remember to choose the correct crown because the other four goldsmiths might very well lose their heads!
2. Complete the *chart that organizes the following data about the 5 crowns in your notebook:
- all of the crowns are identical and have a volume of 180 cm3
- the 5 crowns have the following different masses
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. Answer the *questions on the chart page to help clarify your thinking.
7. Summarize your findings in a letter 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."
You will receive an individual grade for your work on this task. Click here to download the writing rubrics including the following rubric:
By successfully completing this activity, you have learned how to use a property of matter, density, to identify matter.
Click here to read about "Archimedes and the Golden Crown."
Credits & References
Prentice Hall Matter: Building Blocks of the Universe, New Jersey 1997.
Organizer for Persuasive Essay From Inspiration 6.0