Hydrosphere

What is the hydrosphere?

Layer of water on earth

Includes both liquid and solid water

Snow and ice are included in hydrosphere and make up a special layer called the cryosphere

Hydrosphere

How much of our planet is water?

About 75% of the Earth’s surface is covered in water!

There are two main types of liquid water on Earth:

Salt water

Freshwater

Liquid Water

Freshwater! Salt water!

Salt water!

Water with very low salt content

Water found in lakes, marshes, rivers, streams, etc.

Glaciers and icebergs are also made of freshwater!

Freshwater

Freshwater is the only type of water that land animals (and plants) and freshwater organisms can drink

Water that is safe to drink is said to be potable

Freshwater

Potable water has the following characteristics:

Transparent

No suspended particles

No unpleasant odour

Contains few minerals

Contains dissolved oxygen

No disease-causing microorganisms

Potable Water

Why can’t we drink saltwater?

We can’t drink saltwater because it has too many minerals and would actually suck the water out of us to try to balance these excessive salt levels

Freshwater

Water with significant amounts of salt and minerals in it (more than 3%)

The type of water found in seas, oceans and estuaries (where saltwater and freshwater meet)

Saltwater

Why is some water salty?

As water runs over rocks, some of the minerals (salts) dissolve into it

This water collects in rivers which flow into the oceans

Saltwater

Eventually all these mineral salts collect in the oceanAnd since salt does not

evaporate when water does, it stays there!

Saltwater

Water Cycle

Cycle where water goes from being on the surface of the Earth, to being in the atmosphere, and finally going back to the surface of the Earth

This cycle connects the hydrosphere and the atmosphere

This cycle is possible thanks to phase changes

Water Cycle

1 – Evaporation and Evapotranspiration

a. Evaporation: Water in lakes, rivers and oceans heat up and turn into water vapour (gas). Water vapour goes into atmosphere

b. Evapotranspiration: Living things exhale and sweat water vapour. Water vapour goes into atmosphere

Steps of the Water Cycle

2 – Condensation – Cloud Formation

Water vapour in atmosphere cools and condenses to form clouds

Clouds are made up of mini droplets of water

Steps of the Water Cycle

3 – Precipitation – Rain, snow, hail

Mini droplets get bigger until they are too heavy to remain in the atmosphere

Water falls back down to Earth as precipitation (either rain, snow or hail)

Steps of the Water Cycle

4 – Runoff and infiltration

a. Runoff: Excess water flows to a key body of water (ex: lake)

b. Infiltration: Precipitation seeps into the ground and into underground waterways

Steps of the Water Cycle

Humans affect the water cycle through:

Pollution

The removal of vegetation

The paving of natural environments

Changing how water flows: building dams, putting in irrigation systems, etc

Human Impact on the Water Cycle