Name: ______Date: ______Hr: ______

Physical Science – Unit 3

Lab – Determining Density

Introduction:

In this laboratory investigation, you will determine:the density of a liquid, the density of varied sizes of the same substance, and the identity of an unknown sample by finding its density and comparing it to densities of known samples

There are two ways in which we can measure the volume of a solid - either via direct measurement with a ruler or meter stick or via displacement. Displacement involves completely submerging an object under water and noting the amount that the water rises. The volume of risen water is equal to the volume of the object. We will be using both means of measuring volume in this lab.

Materials:

Electronic balance

Cylinder samples of different metals

Different cylinder samples of Aluminum (each group must pick a different Al sample)

Centrigram balanance

YOUR irregular object

Overflow Can

25 mL plastic graduated cylinder

100 mL plastic graduated cylinder

Procedure:

Part A – Determining Density of An Unknown Solid

  1. From the stock table, obtain a sample.

Object / Density (g/cm3)
Aluminum / 2.70
Copper / 8.96
Lead / 11.3
Tin / 7.2
  1. Write the number of your object in the box provided.
  2. Determine the mass of each object and record in the data section.
  3. Calculate the volume of each object via displacement using an overflow can & 100 mL graduated cylinder.
  4. Calculate the density of the object using this data (g/mL).
  5. Use the chart to the right to determine the material that you are working with. If you can’t find a match, you most likely calculated the volume incorrectly. TRY AGAIN!
  6. Repeat this for a second sample with a new number!

Object # / Mass / Volume via displacement / Density / Name of Material

Part B - Determining the density of YOUR irregular solid

  1. In the space below, write a procedure for determining the density of your irregular solid. To receive full credit, you must be very specific and use the correct names of laboratory equipment. (Note: if your object is too big for a graduated cylinder, you will have to use an overflow can!!!)
  1. Then, find the density of your irregular solid using your procedures.

What was your solid:______ / Mass:______ / Volume:______ / Density:______

Part C – Finding the Density of different samples of the same substance

  1. You will be sharing the information that you collect in this section with the rest of the class.
  2. Write the name of the substance that you are working with in the data section.
  3. Find the mass of your object and record it in the data section.
  4. Find the volume of your object via displacement using the 25 mL plastic graduated cylinder. (*REMINDER* - the 25 mL plastic graduated cylinder goes up by 0.5 mL)
  5. Transfer your data to the class data sheet at the front of the room.

Substance:______Letter:______
Volume of substance via displacement:______
Mass of substance:______

CONCLUSION:

  1. When finding the density of your solid in Part B, if your solid had not been completely submerged in the liquid, how would that have affected its:
  2. Mass:______(too high, too low, no effect)
  3. Volume:______(too high, too low, no effect)
  4. Density:______(too high, too low, no effect)
  1. What weighs more, a ton of bricks or a ton of feathers? Explain!!!
  1. What is more dense, a ton of bricks or a ton of feathers? Explain!!!!
  1. Relate what you read about displacement in the introduction section of the lab to what you have noticed when someone gets in a bathtub.