Density and other clues that identify a substance

Answer Key - Grade 8 Science Worksheet - Building Confidence

Circle the best answer, or write your answer on the line.

1. 1.

   An aluminum block has a mass of 27 g and a volume of 10 cm³. Density = mass ÷ volume. What is its density, Ari?

   2.7 g/cm³
2. 2.

   An iron bolt has a mass of 39.35 g and a volume of 5 cm³. Density = mass ÷ volume. What is its density, Esme?

   7.87 g/cm³

3. Read this first

   Density reference table (real data, rounded; NIST and Engineering ToolBox) (real data, rounded)

   substance	density (g/cm³)
   cork	0.2 to 0.25
   oak wood	0.72
   olive oil	0.91
   ice	0.92
   corn oil	0.92
   water	1
   sea water	1.025
   aluminum	2.7
   zinc	7.13
   iron	7.87
   copper	8.96
   silver	10.5
   gold	19.3

4. 3.

   Jun drops a big cork into water. Using the table, does it float or sink?

   • It sinks, since it is big
   • It dissolves
   • It floats
5. 4.

   Kira drops a tiny iron nail into water. Using the table, what happens?

   • It floats, since it is small
   • It sinks
   • It floats, since it is light
6. 5.

   An iceberg can weigh millions of kilograms. Using the table, does it float in water, Luz?

   • It floats
   • It sinks, since it is so heavy
   • It sinks to the sea floor
7. 6.

   Milo has a big aluminum block and a small aluminum block. How do their densities compare?

   • The big one is denser
   • The big one, since it has more mass
   • The same
8. 7.

   Pia cuts a bar of soap in half. How does each half's density compare with the whole bar's?

   • The same
   • Each half is half as dense
   • Less, since each half has less mass

9. Density reference table (real data, rounded; NIST and Engineering ToolBox) (real data, rounded)

   substance	density (g/cm³)
   cork	0.2 to 0.25
   oak wood	0.72
   olive oil	0.91
   ice	0.92
   corn oil	0.92
   water	1
   sea water	1.025
   aluminum	2.7
   zinc	7.13
   iron	7.87
   copper	8.96
   silver	10.5
   gold	19.3

10. 8.

    A metal has a density of 8.96 g/cm³. Using the table, which metal is it, Ren?

    • Silver
    • Copper
    • Iron
11. 9.

    Tala finds a light gray metal with a density of 2.70 g/cm³. Using the table, what is it?

    • Zinc
    • Iron
    • Aluminum
12. 10.

    A block of wood has a density of 0.72 g/cm³. Using the table, which material matches, Zee?

    • Oak wood
    • Cork
    • Ice