Grade 8 Science and Engineering/Enriched Science and Engineering 8 Mr. Cooper/Mrs. Bellitti/Mrs. Malinauskas Name: _________________________ Period: ______ Date: __________ Lab: Using Density Cubes to Understand Density 1. Pick up each of the cubes. Before taking any measurements, make a prediction of their relative densities by listing the items in order from greatest density to lowest density. (Note: Cu=copper, Al=aluminum, Bu=brass, Fe=iron, PVC, acrylic and nylon are all different types of plastic). Explain how you came up with your list: _______________________________________________________________
_______________________________________________________________
_______________________________________________________________ 2. For each cube, find the mass using the triple beam balance and calculate the volume of the cube. Then calculate the density of the substance in g/cm3. Material Mass (g) Volume (cm3) Density (g/cm3) Rank (greatest to least) PVC Brass (Bu) Pine Copper (Cu) Nylon Iron (Fe) Poplar Maple Aluminum (Al) Acrylic 3. Was your initial list correct? Why do the actual densities make sense? _______________________________________________________________
_______________________________________________________________
_______________________________________________________________ Grade 8 Science and Engineering/Enriched Science and Engineering 8 Mr. Cooper/Mrs. Bellitti/Mrs. Malinauskas 4. Given the list of densities above, if you filled a large box with pine and filled another box of equal volume with iron, which one would have a greater mass? Why? _______________________________________________________________
_______________________________________________________________
_______________________________________________________________ 5. Given the list of densities above, if you took exactly 1 pound of acrylic and 1 pound of brass, which one would take up more space? Why? _______________________________________________________________
_______________________________________________________________
_______________________________________________________________ 6. Pick up and compare copper and aluminum. Look at the drawing below of the copper and aluminum cubes and their atoms. What are TWO possible explanations for why the copper cube has a greater mass than the aluminum cube? ______________________________________ ______________________________________ ______________________________________ ______________________________________ ______________________________________ ______________________________________ ______________________________________ ______________________________________ ______________________________________ ______________________________________ ______________________________________ ______________________________________ Practice Questions: 7. If a substance has a high density, what can you guess about the size, mass, and arrangement of the atoms that make up the substance? _______________________________________________________________
_______________________________________________________________
_______________________________________________________________ 8. If a substance has a low density, what can you guess about the size, mass, and arrangement of the atoms that make up the substance? _______________________________________________________________
_______________________________________________________________
_______________________________________________________________ Grade 8 Science and Engineering/Enriched Science and Engineering 8 Mr. Cooper/Mrs. Bellitti/Mrs. Malinauskas Now imagine two blocks (Sample A and Sample B) made of different substances. Each block has the same mass, but different volumes. See the image below: 9. Make a prediction! Before doing any calculations, which sample has a greater density? Explain why you think this is the case. ___________________________________________ ___________________________________________ ___________________________________________ ___________________________________________ ___________________________________________ ___________________________________________ ___________________________________________ 10. Now find the density of each sample (make sure to include units!). Show your work here: 11. Was your prediction correct? Explain why the actual answer makes sense. _______________________________________________________________
_______________________________________________________________
_______________________________________________________________ 12. What would be the density of sample A if we cut the block exactly in half? Explain WITHOUT doing any calculations first! (If you want to check your answer, go ahead and calculate it afterwards.) _______________________________________________________________
_______________________________________________________________
_______________________________________________________________ 13. In your own words, describe what the density of a substance is. Try to explain it as though you were explaining it to a second grader. _______________________________________________________________
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________