Transcript Human Impact on Environment

The Air Around You
Weather- the condition of Earth’s atmosphere at
a particular time
Atmosphere- envelope of gases that surrounds
the planet
Composition of
Atmosphere
Nitrogen
Oxygen
Carbon
Water vapor
Trace gases
Oxygen
Why do we need Oxygen?
Animals
Fuels fire
Other processes such as oxidization and rusting
Ozone- made of 3 oxygen atoms; protects us
from UV radiation
Importance of the
Atmosphere
Supports life
Maintains temperature
Protects Earth from
space debris
Properties of Air
Is air matter?
Yes, air is matter because it has mass and takes up
space
Density
D=M/V
Pressure- the force pushing on an area or surface
Air pressure can vary from day to day
Measuring Air Pressure
A barometer is an instrument used for
measuring air pressure
Air pressure is measured in inches
Two Types:
Mercury
Aneroid
Types of Barometers
Aneroid
Mercury
Altitude Affects
Altitude, or elevation, is the distance above sea
level
Air pressure decreases as altitude increases
As air pressure decreases, so does its density
Think About It…
In what ways
do humans
impact the
environment?
Homework
Visit this site and take the survey:
http://islandwood.org/kids/impact/footprint/footprint.
php
Record your results
How many football fields would it take to support you as
an individual?
How many worlds would it take if everyone lived the
same way?
My Results
As an Individual…
the land needed to grow all the food, provide materials to
make everything they use and wear, and then clean and
recycle all the the waste and byproducts of one person would be the size of 9 football fields all connected
together!
Considering Everyone…
I all six billion people who currently live on our planet had
these same living conditions and habits, it would take 3.2
Earths to support us.
Our Atmosphere
How does our atmosphere trap and hold on to
heat?
Energy from the sun is transmitted to Earth via
electromagnetic radiation, which is either:
Visible light
Non-visible (UV and infrared)
Energy in Earth’s
Atmosphere
Some sunlight is absorbed or reflected by the
atmosphere before it can reach the surface. The
rest passes through the atmosphere to the
surface.
Energy at Earth’s Surface
Greenhouse effect- The
process by which heat is
trapped in the
atmosphere by gases
that form a “blanket”
around Earth.
Heat Transfer
Types of Heat Transfer:
Convection-The transfer of thermal energy by the
movement of a fluid.
Conduction-The direct transfer of thermal energy
from one substance to another that it is touching.
Radiation- heat you can feel, but cannot see
What Causes Climate
Change?
Changes in Earth’s position relative to the sun
Changes in the sun’s energy output
Major volcanic eruptions
Movement of continents
Human impact
Our Impact
While there are many natural reasons for climate
change, scientists have found that humans can
also have an impact
In the last 120 years, the average temperature in
the troposphere has risen 0.5 * C
Global warming- A gradual increase in the average
temperature of Earth’s atmosphere.
The Greenhouse Gases
Hypothesis
Until the 1800’s, the level of CO2 in the
atmosphere remained the same
Think: what significant event in history occurred
around this time?
Greenhouse gases: gases in the atmosphere
that trap energy; ex: methane, CO2, water vapor
Climate Variation
Hypothesis
Not all scientists agree with the theory of global
warming and believe that climate variation may
be a natural and normal occurrence
Effects of Global Warming
Ozone Depletion
Ozone in the stratosphere filters out much of the
harmful ultraviolet radiation from the sun
What do you think ozone depletion means for the
environment and for humans?