Revision as of 05:56, 28 March 2019

Hydrosphere

Think and Share

LEARNING ACTIVITY REQUIRED - WENOTE DISCUSSION

(: Avoid using iDevices as replacements for headings. Typically iDevices should only be used when the learner must actually do something other than reading. Keep normal text as normal text. I recommend removing the iDevice below for the water cycle and replacing with the normal heading syntax for wikis, not using HTML markup for specifying headings.)

The water cycle

Earths water distribution

In the infographic, on the water cycle (above), you can see the main elements of the water cycle, which involves the geosphere, the hydrosphere, and the atmosphere. Although H2O is mainly liquid, it can also be a gas in the atmosphere or a solid (ice) in the atmosphere, mountain tops, or ice caps. The infographic below tells us where the water is stored on Earth and in what form. Note that most of the water is in the liquid state in the world's oceans and seas and is salty. Freshwater is only 3% of all the Earth's water, and most of that is in the form of ice.

(: Avoid stating the question of the quiz in the title of the IDevice. This will minimize export opportunities of quiz items because the question is not contained within the item. I've tweaked the iDevice below - check the history tab. Also in the feedback - you were referring to the table on the right. On a mobile device, the table will not necessarily appear on the right of the screen, typically above. I've changed the feedback options to reflect this.)

Which water reservoir holds its water the longest?

Review the following table summarising the earth's water reservoir and answer the question which follows.

• Which water reservoir holds its water the longest?
  • The atmosphere
    • Incorrect. Review the table above OR think a little "lower".
  • The ocean
    • Incorrect. Review the table above .
  • Groundwater
    • Correct. Well done, read below for more information.
  • Lakes
    • Incorrect. Review the table above.
  • They all hold water for the same amount of time.
    • Incorrect. There is a better answer available to you, try again.

(: The text below should be contained in the feedback for Ground water. Its unnessary duplication here. Also to keep our markup clean, avoid where possible, hard coding layout which deviates from standard CSS)

(: When using more than one quiz on the same page, each requires a unique ID. That is z01, z02, z03 etc.)

Does more water evaporate from the ocean, or from the land?

Water transfer between reservoirs in the water cycle

• Select one from the below
  • The Ocean
    • Correct. Well done, there is a significant difference between the two, which leads us to the question below.
  • The Land
    • Incorrect. Consider using the table to your right.

Ocean Waves

• Ocean precipitation = 398,000 km3/year
• Ocean evaporation = 434,000 km3/year

Water - Unique characteristics that make water what it is.

In this section we consider the unique properties of water, and how these affect global temperature, weather and climate.

Unusual Properties of Water

How do these unique properties of water affect global temperatures?

• The oceans can hold a lot of energy without changing temperature – thermal inertia
• Important vehicle for heat and energy transfer between the oceans and atmosphere
• Transfers energy from the equator to the poles
• Thawing and freezing of ice at the poles moderates global temperatures, absorbing and releasing energy without changing ocean temperatures

What about ocean circulation? How does that affect weather and climate?

• Ocean circulation can be divided into surface and deep currents
• The surface currents are driven by the winds, by the rotation of the earth, and by differences in seawater density, which cause differences in the height of the sea surface
• Deep ocean circulation, also known as the thermohaline (thermo = temperature, haline = salt) circulation, is driven by density differences, caused by differences in temperature and salinity
• Both deep ocean and surface ocean circulation move heat, gases, and nutrients around the planet, and play a key role in climate and weather
• Learn more by watching this short video on the deep ocean circulation and its role in climate