4.1 Water systems

Guiding question

How can natural systems be modelled, and can these models be used to predict the effects of human disturbance?

This video aligns with the slide deck above and the guided student notes at my TPT store.

Click here for a set of SL flashcards with essential vocabulary from topic 4.1 Water systems.

Here’s a Blooket game to play using the above SL flashcards for topic 4.1 Water systems.

SL and HL knowledge statements

4.1.1 Movements of water in the hydrosphere are driven by solar radiation and gravity.

4.1.2 The global hydrological cycle operates as a system with stores and flows.

4.1.3 The main stores in the hydrological cycle are the oceans (96.5%), glaciers and ice caps (1.7%), groundwater (1.7%), surface freshwater (0.02%), atmosphere (0.001%), and organisms (0.0001%).

*Diagram of water stores by Woudloper via Wikimedia Commons*

An Introduction To Groundwater

Here’s a great page to help you understand how aquifers work, including an opportunity to build your own groundwater model.

4.1.4 Flows in the hydrological cycle include transpiration, sublimation, evaporation, condensation, advection, precipitation, melting, freezing, surface run-off, infiltration, percolation, streamflow and groundwater flow.

4.1.5 Human activities, such as agriculture, deforestation and urbanization, can alter these flows and stores.

4.1.6 The steady state of any water body can be demonstrated through flow diagrams of inputs and outputs.

Knowledge statements for HL ESS only

Click here for a set of HL flashcards with essential vocabulary from topic 4.1 Water systems.

4.1.7 Water has unique physical and chemical properties that support and sustain life.

4.1.8 The oceans act as a carbon sink by absorbing carbon dioxide from the atmosphere and sequestering it.

4.1.9 Carbon sequestered in oceans over the short term as dissolved carbon dioxide causes ocean acidification; over the longer term, carbon is taken up into living organisms as biomass that accumulates on the seabed.

4.1.10 The temperature of water varies with depth, with cold water below and warmer water above. Differences in density restrict mixing between the layers, leading to persistent stratification.

4.1.11 Stratification occurs in deeper lakes, coastal areas, enclosed seas and open ocean, with a thermocline forming a transition layer between the warmer mixed layer at the surface and the cooler water below.

4.1.12 Global warming and salinity changes have increased the intensity of ocean stratification.

4.1.13 Upwellings in oceans and freshwater bodies can bring cold, nutrient-rich waters to the surface.

4.1.14 Thermohaline circulation systems are driven by differences in temperature and salinity. The resulting differences in water density drives the ocean conveyor belt, which distributes heat around the world and thus affects climate.

This is a cool video from NASA showing Earth’s ocean currents.

The AMOC has a major influence on European climate.

Practical activities

Practical 4.1.4: Create and use a systems diagram showing the transfers and transformations of the hydrological cycle.
Add from existing PSOW booklet.

Possible engagement opportunities

Investigate your water usage over a weekend and compare this to water use in other countries or other socioeconomic groups where you live.
Investigate the impact of human activities on the water cycle where you live. Summarize your findings in promotional material for your school or local community.
Initiate water-saving behaviours in the school community through advocacy.
Turn into CAS suggestions connected to UN SDGs.

Happy learning!