AlgebraLab

Salt Water Density

By E Saylor

Previous knowledge: As the amount of dissolved salt increases, a salt water solution becomes denser.
 
Purpose: In this activity, you will prepare a set of 5 salt water solutions. In order to distinguish them easily, each solution will have a different color. After preparing the solutions, you will experiment with them to study how solutions of different densities can maintain separate layers. Using this knowledge, you will determine the % of salt in a sample of sea water. 
 
Materials/Procedure:
 
  1. Prepare a set of 5 salt water solutions of different densities, each tinted a different color, using:
 
    • 5 plastic cups
    • Permanent marking pen
    • Salt
    • Water
    • Electronic balance
    • Food coloring
 
  1. Investigate how the solutions of different density can maintain separate layers, using:
 
    • 5 test tubes
    • Test tube rack
    • Hollow glass rod, 15 cm in length
    • Beaker to act as a container for waste
    • Prepared set of salt water solutions
 
  1. In the final activity, you will need to determine the % of salt in ocean water. You will need:
 
    • Test tube
    • Ocean water