Precision Lab. Question: What is the density of 2 unknown liquids, and how precise are the measurements used to make the calculations?

Authors Avatar

IB # 000345-153

Measuring Precision in Liquid Measurements

IB Physics SL Lab

9-03-11

IB Physics SL


Question: What is the density of 2 unknown liquids, and how precise are the measurements used to make the calculations?

Introduction:

        Background Information: The density of a liquid, ρ, is calculated by dividing mass by volume, m/v. This quantity, thus, is a measurement of the mass of an object per cubic unit. Precision can be defined as the accuracy of a measurement when compared to other measurements, not necessarily accurate when compared to the theoretical measurement.  In other words, all measurements made are within error range of each other, and are thus qualified as being precise.

Materials:

  • 2 unknown liquids: one blue and one green.
  • A liquid of known density: ethyl alcohol.
  • A 100 mL graduated cylinder
  • A balance
  • 2 250 mL beakers
Join now!

Method:

  1. Put each unknown liquid into a beaker.
  2. Bring the beakers to your workstation.
  3. Put the empty graduated cylinder onto the balance, and tare it.
  4. Pour 10 mL of one unknown liquid into the graduated cylinder.
  5. Weigh the graduated cylinder.
  6. Repeat steps 4 and 5 until 50 mL have been poured and weighed.
  7. Pour out the graduated cylinder, and wash and dry it.
  8. Repeat steps 3-6 for the other unknown liquid and the ethyl alcohol.

Data:        

Density:

        Liquid A: 52.62/ 50  =  1.0524

        Liquid B: 52.53/49.9 =  1.0527

        Isopropol alcohol ...

This is a preview of the whole essay