Made Possible through support of

Meridian Energy

Run with the support of

Department of Conservation


Water / Wai

Water / Wai

The Earth is a watery place. But just how much water exists on, in, and above our planet?

About seventy one percent of the Earth's surface is water-covered, and the oceans hold about ninety seven percent of all Earth's water. Water also exists in the air as water vapor, in rivers and lakes, in icecaps and glaciers, in the ground as soil moisture and in aquifers, and even in you and your dog.

Water is never sitting still. Thanks to the water cycle, our planet's water supply is constantly moving from one place to another and from one form (physical state) to another. Things would get pretty stale without the water cycle!

(Information from: USGS Science for a changing world.)

Did you know that you drink dinosaur pee every day? Earth’s water is so old that, statistically speaking, every time you drink a glass of water, you’re probably swallowing a water molecule (H2O) that passed through a dinosaur.

We are all aware that most land plants (e.g. beech trees!) use photosynthesis to grow and produce the oxygen we breathe. But roughly half of the total photosynthesis on Earth occurs in the surface of the ocean, carried out by tiny micro-algae called phytoplankton.

Water is tasteless, almost colourless, transparent and odorless. It also is the only natural substance that is found in all three physical states (liquid, solid and gas) at the temperatures normally found on Earth. Moreover, life totally depends on it. Not bad for a boring looking substance!

Of the small amount that is available as freshwater, only a fraction is readily available for our everyday use (like drinking water). This explains why water is such a precious resource, even though it seems like we have such an abundance of it.

Water also has the power to shape the landscape... but this is next week's story.

Questions Asked

  1. img


    27th July 2019

    Can water escape the water cycle?

    1. img


      27th July 2019

      The water cycle is a closed system. In Science, a closed system is a system that does not interact with other systems (basically nothing gets in and nothing gets out). However, water vapour can escape from the upper atmosphere, but very minimal loss occurs. (From:

Have a Question?

Your email will not appear on the page, it is used to email you once your question has been answered.

Thank you for asking a question! Your question has been sent, it will appear on this page along with the answer once it has been approved, we will email you once it has been answered.