1. Examine and hold each cube, and predict whether it will sink or float in water. Record your predictions in Table 1.

Table 1: Density Table

MATERIAL / PREDICTION (sink or float) / MASS (g) / VOLUME (cm3) / DENSITY (g/cm3) / RESULTS (sink or float)
STEEL
WOOD
ALUMINUM
COPPER
PVC
ACRYLIC
NYLON
  1. Use the balance to determine the mass of the cubes and record in table 1
  2. Determine the volume of the cubes by measuring the length, width, and height and multiplying these dimensions. Record in table 1.
  1. Calculate the density of the cubes by dividing the mass by the volume. Density (g/cm3) = mass (g) / volume (cm3). Record the density values in table 1.
  1. Explain why these cubes have different densities.
  1. Did you notice any pattern between the density of an object and its ability to sink or float? Explain.

PART II. SINK OR FLOAT

  1. Measure the block of clay’s mass. Record it in Table 2.
  2. Find the volume of your clay using the displacement method:
  3. Place a disposable cup under the displacement tank spout
  4. Fill the tank until water begins to run out of the spout
  5. When the water stops flowing remove the cup and replace it with a dry beaker
  6. Place your clay into the tank and collect the water that runs out of the spout.
  7. Quickly remove your clay and dry it with a paper towel or it will get slimy.
  8. The volume of the water you collected is equal to the volume of your clay. Use the graduated cylinder to measure the volume and record it in Table 2.
  9. Calculate the density in g/mL and record it in Table 2.

Table 2: Density Data for Clay

SUBSTANCE / MASS (g) / VOLUME (mL) / DENSITY (g/mL)
CLAY
  1. Use the entire block of clay from above and mold it into a shape that you think will float.
  2. Test the shape in a container of water. When you have successfully made a boat that floats take it out of the water and dry it.
  3. Measure the mass of your boat and record it in Table 3.
  4. Use the displace tank just as you did above.
  5. Measure the volume of the water displaced by your clay boat.
  6. Record this data in Table 3.
  7. Use you data to calculate the apparent density of your clay boat.

Table3: Data for Boat

MASS OF BOAT (g) / Volume of water displaced by the boat (mL) / Apparent Density (g/mL)
  1. Which displaced more water, the stick of clay or the clay boat?
  1. How do you explain the difference in the volumes?
  1. Explain why a solid stick of clay sinks but a clay boat can be made to float.