Convection in the Ocean Activity

Materials

  • Aluminum pie pan
  • Small piece of clay
  • Clear, colorless plastic straw (only clear will work well)
  • 3 16 oz.cups filled with three different solutions.
  • Three pipettes, one for each solution
  • Blue, green, and red colored pencils

Procedure

1. Stick the plastic straw in a square cube of clay. Make sure the straw doesn’t quite go throughthe bottom of the clay.

2. Pour some tap water into the straw to make sure that it is leak proof.

3. To empty the straw, pick up the whole assembly and turn it upside down in the sink.

4. Drop about 10-15 drops of the first color you choose to use in the straw (it works best to slightly tip the straws).

5. Drop about 10-15 drops of the second color you choose to use in the straw.

6. Drop about 10-15 drops of the third color you choose to use in the straw (note – if the liquids mix, start over with a new trial).

7. After you successfully layer the liquids, repeat the process four times in a different order.

8. Record your results on the worksheet.

9. After each trial the straw should be emptied into the pie pan.

Names ______

______

Convection in the Ocean Activity

1. Hypothesize which color of water (ocean, fresh and brackish [found at the mouth of rivers]) is…

a. The most dense and why.

______

______

b. The least dense and why.

______

______

c. Middle density and why.

______

______

2. Record the results of your four trials.

3. When the three colors layered which was on the…

a. Top? ______

b. Middle? ______

c. Bottom? ______

4. Now label the fresh water, brackish water and ocean water.Explain why they are layered as they are.

a. Top? ______

b. Middle? ______

c. Bottom? ______

Teacher Notes

Make the salt solutions:

  • “Ocean water”
  • Two cups of water.
  • Add 6 tablespoons salt.
  • Stir until dissolved.
  • Add 20 drops of blue food coloring.
  • “Brackish water”
  • Two cups of water.
  • Add 2 tablespoons salt.
  • Stir until dissolved.
  • Add 20 drops of red food coloring.
  • “Fresh water”
  • Two cups of water.
  • Add 20 drops of green food coloring.

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