Transcript Why_we_need_the_Sun[1]

The Sun
We can’t live without it!!!
Without the Sun, life on
planet Earth would be
IMPOSSIBLE!!
The Sun does MANY things that make life on
this planet possible!
Provides the heat needed for life
Fuels photosynthesis
Keeps the Earth in orbit
Did you Know…?
The Sun gives off as much energy as 1 TRILLION megaton
bombs…EVERY SECOND!!
This energy is what keeps us alive…we use it in a variety of
ways that are CRUCIAL to human life!!
Heat
The sun's rays hit the equator at a direct angle between 23 °
N and 23 ° S latitude. Radiation that reaches the atmosphere
here is at its most intense.
In all other cases, the
rays arrive at an angle
to the surface and are
less intense.
The closer a place is to
the poles, the smaller
the angle and
therefore the less
intense the radiation.
The distribution of global climate zones is caused by the
decrease in solar energy as latitude increases from the
Equator toward the poles.
The climate of a region will determine what plants
will grow there, and what animals will inhabit it.
Two things determine what kinds of crops can grow in
an area
1. Temperature
2. Moisture level (precipitation)
Without the Heat from the
Sun , evaporation and
transpiration would STOP.
That would end the water
cycle…
Which would be the end of
crops growing.
No crops = No food!!
No food = No life!!
The Greenhouse Effect
The Greenhouse Effect traps in the heat from
the Sun and provides the warmth necessary for
life on Earth
Without the
Sun there
would be NO
HEAT for the
atmosphere
to trap!!
Without the Sun we would also lose the ozone layer .
It is created by the action of the Sun's light on the
upper atmosphere.
1. Sunlight splits an O2
molecule into 2 single
O molecules
2. These single O
molecules join another
O2 molecule, forming
an ozone (O3) molecule
With no ozone, ultraviolet rays (UV-B specifically) are
easily able to penetrate the earth's atmosphere and
exposure to UV-B rays has been linked to the
increased occurrence of cancer, mutations, and
immune system diseases.
Skin Cancer
The lack of an ozone layer would also result in
temperatures that are HIGHER than we can
withstand.
The land would be unable to hold
moisture…therefore we would have no crop
growth.
Speaking of crop growth…
Sunlight provides the fuel
for photosynthesis!
Photosynthesis gives us 2
ESSENTIAL things…
FOOD
and OXYGEN
In one way or another
ALL FOOD is made from
the SUN!!
No Sun = No Photosynthesis
No Photosynthesis = No FOOD and No OXYGEN
NO LIFE!!
Remember the KT Extinction?
What caused the
extinction of the
dinosaurs?
EVERY living thing needs ENERGY to survive.
PRODUCERS make their own food through PHOTOSYNTHESIS
(plants mostly)
CONSUMERS cannot do this so they MUST EAT to get their
energy.
ALL of the energy in the food chain originally came
from the SUN!!
The Sun Keeps Earth in Orbit
How massive is the Sun?
It contains 99.8% of ALL MATTER in our Solar System.
The Sun is big enough that it could hold 1.3 MILLION Earths inside of it!!
THE BIGGER AN OBJECT…THE STRONGER ITS GRAVITATIONAL PULL!!
Without the Sun’s gravitational pull the Earth would float through
space.
Some scientists believe that Earth would eventually be pulled into orbit
around Jupiter.
If the Sun ‘shut off’…how long would we
survive…and what would life be like?
It would take 8 minutes for us to even realize that the Sun
shut off. It would take that long for darkness to reach us.
Within a week the global temperature would drop below 0°F.
With a year, it would drop to
-100°F
The top layer of the oceans would freeze over. Ironically, this
would insulate the deep water below and would prevent the
oceans from freezing solid for hundreds of thousands of
years.
Eventually our planets temperature would reach -400°F (the
temperature at which the heat radiating from the planets
core would equal the heat that the Earth radiates into space.)
Although some microorganisms (bacteria,
etc.) living in the Earth’s crust MIGHT
survive, the MAJORITY of life would only
enjoy a BRIEF post-sun existence.
Photosynthesis would stop IMMEDIATELY,
and most plants would die within a few
weeks.
With the food chain’s bottom tier knocked
out most animals (HUMANS INCLUDED)
would die off quickly without food.
Scavengers (animals that eat dead matter)
could live off the rest of us dead guys for
quite a while…until the cold eventually kills
them too!!
But, what will most likely happen is humans will be extinct
long before the Sun burns out, but if we were around still,
maybe this is what we would expect.
Video Clip
Classwork/Homework Assignment
Your assignment is to construct a book/pamphlet about the
sun…and why it is ESSENTIAL for LIFE!
The following must be included in your book:
1. The Sun’s influence on :
a. Heat of the planet
b. Ozone layer
c. Photosynthesis
d. Food Chains
e. Earth’s orbit
2. At least 1 colorful picture for EACH influence above.