Planetary Heat Pumps

Brief description

In this set of three activities, students will learn how ocean circulation has an impact on climate. In the introductory activity, they carry out calculations to compare the relative impact of global warming on the atmosphere and oceans. A practical activity using readily available equipment allows students to see how water of different temperatures can form layers in the ocean and to consider how they might use this to explore the effect of changes in salinity. In the final activity, students use the Climate from Space web application to find out more about the Gulf Stream.

Subject Geography, Science, Earth Science

Learning Objectives
  • Carry out calculations to compare the role of the oceans and atmosphere in regulating the climate
  • Explain how the global thermohaline circulation arises
  • Describe how ocean currents transport water and energy around the Earth
  • Use a model to examine the movement of water of different temperatures and explain stratification in the ocean
  • Design practical methods of investigating a question about how water moves in the oceans
  • Describe the behaviour of the Gulf Stream using information from climate data
  • Synthesise data from records of at least two essential climate variables to explain an observed correlation or trend
Age range
14 – 16 years old
approximately 45 minutes per activity
Resource available in:
Activity 1: Planetary heat pumps
In this reading-based activity, pupils will be led into calculations using specific heat capacity. The relevant equation is given so students do not need any prior knowledge of the term. Either or both parts of the activity (the reading and the calculations) could be set as homework depending on the ability of the clas. 
Activity 2: Rising and falling water 
In this practical activity, students replicate ocean thermodynamics in a container, using coloured water to track flows and see how layer of water at different temperatures are formed and maintained. They are challenged to consider how they can use the model to demonstrate other aspects of ocean circulation. 
  • Large transparent container per group
  • Small container per group to  submerge in the larger container
  • Plastic bags
  • Rubber bands or string
  • Food colouring or ink
  • Ice in a bucket for cooling, or refrigerated water
  • Access to hot and cold water
  • Stopwatch or clock per group (optional)
  • Camera or smartphone per group (optional)
  • Thermometers (optional)
  • Cloths or paper towels
  • Student worksheet 2 (2 pages)
  • Materials for creating posters, or software for creating videos or presentations
  • Climate from Space online resource: Planetary Heat Pumps story (optional)
Activity 3: The Gulf Stream 
In this activity, students use the Climate from Space web application to look at sea surface temperatures along the path of the Gulf Stream and downloaded data to compare patterns and trends across the Gulf Stream with those seen elsewhere in the North Atlantic. They then research and explain links between sea surface temperature and another climate variable using understanding developed while studying the topic. 

Did you know?

Before the age of satellites, the temperature of the ocean could only be measured using thermometers linked to the shore, lowered from ships, or attached to buoys or submersibles. This, of course, meant that measurements were patchy and there were continuous records for very few places. Thermal cameras on satellites can detect the surface temperature of the ocean across the whole world at regular intervals. A satellite in geostationary orbit can view each section of the sea in a particular hemisphere once every fifteen minutes or so; one in a polar orbit, closer to the Earth, can see more detail and cover the entire planet but will only measure the temperature at a particular place every ten days or so.

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