1.4.1 Hot, Cold and Currents

Objective

Students will explore how changes in the salinity and temperature of water affects its density and motion.

Materials for each group of 3/4 students

• food coloring
• ice cube tray (see Procedure, Step #1-colored ice cube must be made in advance)
• large glass bowl or small aquarium tank (clear plastic bottles if large enough)
• hot tap water (43°C or 110°F)
• small bottle of ink
• salt
• test tube or cup
• Celsius or Fahrenheit thermometer
• safety goggles
• Activity 1.4.1 Student Worksheet, "Hot, Cold and Currents"

Engage

In winter months, primary production in the Antarctic Ocean is nearly zero, which creates difficulty for the grazers who depend on primary production. But in the 5-6 months of austral spring and summer, these waters become a nutrient-rich pasture for plankton. The frigid polar waters teem with life. Part of the reason lies in the density and movement of the water column which is affected by temperature, salinity, changes in pressure (depth) and sediment suspension. We can illustrate how these factors work in some simple lab experiments.

Explore

Procedure

1. Organize students into lab teams. Hand out Activity 1.4.1 Student Worksheets and review materials and procedures. Review lab safety rules. Complete hands-on laboratory investigations.
2. When lab is completed, have students share observations and conclusions. Reinforce relationships between sea ice and ecosystem in Antarctica.

• Back to Table of Contents.
• Back to Activity 1.4.
• On to Activity 1.4.2.
• On to Activity 1.5.

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Last Update: 1/18/97
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