1. The Hydrosphere and Biosphere
Objectives:
Name the three major processes in the water cycle.
Describe the properties of ocean water.
Explain how the ocean regulates Earth’s temperature.
Discuss the factors that confine life to the biosphere.
Explain the difference between open and closed systems.

2. The Hydrosphere One of the four parts that make up the Earth.
Hydrosphere – all of the water at or near the Earth’s surface.
Includes fresh and salt water.

3. The Water Cycle
Water cycle – the continuous movement of water into the air, onto land and then back to water
Evaporation – liquid water is heated by the sun and rises into the air as water vapor
Condensation – water vapor sticks to dust particles and form clouds
Precipitation – water falls from clouds as rain, snow, sleet or hail

4. The Earth’s Oceans
In order of size
Pacific
Atlantic
Indian
Arctic

5. Salt Water
Seawater is mostly chlorine and sodium

6. Ocean Temperature Zones
Surface layer – warmest layer at the top
Thermocline – middle layer, colder than the surface
Deep layer – bottom coldest layer

7. Oceans Regulate the World’s Temperature
The oceans absorb and store energy from sunlight.
They release energy more slowly than land.
So the temperature of the atmosphere changes much more slowly than it would if there were no oceans.
With no oceans, the temperature of the atmosphere would change change too quickly for living things.

8. Freshwater Sources of freshwater
Groundwater – our source of drinking water that is collected when water trickles through the ground
Aquifer – the layer of rock that stores and allows the flow of groundwater

9. Aquifers Some of your drinking water comes from aquifers
Aquifers can become contaminated by
Leaky landfills
Chemicals (like road salt) and waste poured down storm drains
Fertilizers and pesticides that wash off of crops
Saltwater that seeps in from the ocean
Waste from nuclear power plants

10. Aquifers Assignment: Which aquifer does your town use?
How big is this aquifer?
How many gallons are pumped out of this aquifer each year?
How many people use this aquifer?
Has this aquifer been contaminated in the past? When? With what type of contaminant? How was the situation fixed?

11. The Biosphere
Biosphere – the narrow layer around the Earth’s surface in which life can exist.
From 12 kilometers down to 9 kilometers up
Why?

12. Earth As A System
A system is a collection of interdependent parts enclosed within a defined boundary. 
Examples
How is the Earth a system?
Closed system – energy enters and exits the system but matter does not
Open system – both energy and matter enters and exits the system
Which type of system is Earth? Why?