image description Education & Camps

Compare Fresh and Salt Water

Grades 5-12

 

MATERIALS

2 beakers or jars

SaltWaterproof pen

Plastic strawClayGraduated cylinder

RulerWaterSpoon

Scissors2 aluminum pansHand lens

 

OBJECTIVE

Students will better understand density as it relates to fresh water and salt water.

 

TIME REQUIRED

45-60 minutes

 

PROCEDURES

  1. Fill each beaker with 200 ml water. Stir in two spoonfuls of salt into one beaker.
  2. Cut a 10 cm piece from the plastic straw, discard remaining piece.
  3. Construct a "floater." Make a ball of clay about .5 cm in diameter. Push the end of the straw into the clay. Place the floater into the beaker of freshwater. The straw part of the floater should stick straight up. Mark the water level on the straw with the permanent marker.
  4. Construct a "floater." Make a ball of clay about .5 cm in diameter. Push the end of the straw into the clay. Place the floater into the beaker of freshwater. The straw part of the floater should stick straight up. Mark the water level on the straw with the permanent marker.
  5. Pour 10 ml of water into one aluminum pan. Pour 10 ml of saltwater into the other pan. Place both pans in a warm place. Allow the water to evaporate.
  6. Carefully examine both pans with a hand lens. What did you learn?

 

NOTE: This demonstration works best as a review activity. Have the students cite the characteristics of the red mangrove and dress the volunteer with the materials appropriate for the particular simulation.