Science Concepts—Deep Density Drivers

Summary: Ocean currents redistribute heat around the world and affect the world’s climate. In this topic guide, students use a model to find out how density drives deep ocean currents, and use the information to describe the potential impacts an influx of fresh water could have on ocean circulation.

Concepts to teach:


  1. Density in the ocean drives deep global currents
  2. Deep ocean currents affect the earth’s climate
  3. Increased Arctic ice melt could slow deep ocean currents

Standards: NGSS Performance Expectations

  • MS-ESS2-6. Develop and use a model to describe how unequal heating and rotation of the Earth cause patterns of atmospheric and oceanic circulation that determine regional climates.

Specific Objectives:
Students will be able to:

  1. Explain how and why the melting rate of an ice cube is different in fresh water compared to salt water
  2. Use a model to demonstrate how density driven ocean currents work
  3. Describe how an influx of fresh water in the Arctic could affect ocean circulation

Activity Links and Resources:

  • Experiment: Will an ice cube melt faster in fresh water or salt water? from MIT Blossoms.
    • Students explore concepts of density by conducting an experiment comparing the rate an ice cube melts in fresh water and in salt water. The activity provides a foundation for understanding deep ocean circulation.
    • Includes a video lesson, teacher’s guide, worksheets, and an assessment rubric.
  • NOAA Multimedia Discovery Mission Lesson 8: Ocean Currents
    • The Video Lesson provides narrated animations describing surface currents and deep ocean currents, and the Global Impact sections describes how increased ice melt in the Arctic could affect deep ocean circulation.
  • Online image: Major Ocean Currents viewer from NOAA National Weather Service JetStream webpages


  • Assessment rubric included in the MIT Blossoms lesson