Science 8 Unit 1

Front

Water

Back

-the most important chemical on the planet

-we only need water to survive

-only 2.5% of water is fresh

-we can access less than 1% of that water

• * in order to keep keep up with human demand, we use a variety of means to turn salt water into fresh, reusable water, for example, desalinization.

Front

Where is all the water?

Back

• -The Earth is divided into 3 distinct areas

• 1) Lithosphere

• - this includes the rocky section of our planet, the earth crust

• 2) Atmosphere

• - this includes the gases that surround our planet, the air around us

• 3) Hydrosphere

• - this incudes the water that makes up our oceans and all of the water in and around the land

• - it also incudes all of the water in the air around us

• - includes all of the polar ice caps and glaciers (this ice makes up a significant portion of our fresh water

• -there is also a huge amount of water under us - this is called ground water

Front

What is the water cycle

Back

• The water cycle is a complicated combination of processes that clean and filter out water.

Front

What are the processes of the water cycle?

Back

1) Evaporation

-liquid water turning into gaseous water vapor

2) Condensation

• - water vapor cools into clouds

• 3) Precipitation

• - clouds cooling further and releasing water as rain/snow

• 4) Runoff

• -liquid water running down mountains to lakes/oceans

• OTHER PROCESSES

• 5) Transpiration

• -plants/trees release water through their leaves which then evaporates

• 6) Ground water/ ocean storage

• -much of the world's water is kept in storage

Front

The difference between ocean water and fresh water

Back

• -Ocean water is very different then the water we deal with on a daily basis

• - the salt content of the water means that it acts differently in almost every way

• Salinity: ocean: more salt (35g/l)

• fresh: less (0 g/l)

• Density: ocean: more dense (1.022 kg/l)

• fresh: less dense (1.000 kg/l)

• Freezing point: ocean: lower (-1.9C)

• fresh: higher (0C)

Front

Why do we call ocean water salt water?

Back

-you will notice that ocean water has a much higher salinity (salt content) then fresh water

• -that's why we call it salt water

• - this salt influences the way water ocean water acts

• - it is heavier than fresh water, but also freezes at a lower temperature

Front

What are some sources of fresh water?

Back

1) drainage basins

2) ground water

3) glaciers

Front

What are Drainage Basins?

Back

• - water makes its way to the ocean

• - water runs down mountains and hills and even across land to the nearest river

• - those streams and rivers combine into larger rivers until they make their way to the ocean

• - the area of land that shares a system of rivers is called a drainage basin

• - in NL they are sometimes called water sheds

Front

What is Ground Water?

Back

• -while the ground can be very hard, there are gaps and spaces in between the particles of dirt, sand and rock

• - water slips into these spaces and forms a layer between the surface

• - we call this Ground Water

• - Ground Water is incredibly important as it acts as storage for fresh water

• - we have also learned to harness ground water as a source of fresh water for drinking an human use

• - 35% of human fresh water usage comes from ground water sources

Front

What are Glaciers?

Back

• - There are areas of the world that are so consistently cold through the year that ice never melt. In these areas, it is possible to see huge masses of ice that cover large areas of land. As the bottom layers melt, it creates a layer of water between the ice and land which allows the glaciers to actually move

• - Two Thirds of the world's fresh water is stored in glaciers around the world.

• - The movement of the glaciers during the ice age shaped and formed many of the land masses on our planet

• - Scientist estimate that up to 28% of the planet was covered in glaciers