In the Season 2 finale, Chummy and PC Noakes face several challenges; Fred is thrilled when his daughter and her infant son arrive for a visit; Jenny meets a potential suitor; and Nonnatus House is targeted for demolition.
This mini-series is a dramatization of the real-life story of Harry Gordon Selfridge, the flamboyant and visionary American founder of the famous London department store that revolutionized the modern shopping experience.
WY Field Trip - Wind Farm - Facts
Wind energy is the fastest growing source of electricity in the world,
according to the U.S.
Department of Energy. Let's learn about wind energy,
and wind farms and watch some videos
about Wind Farms in Wyoming.
But First...the basics...
What is Wind? Wind is air
makes the wind?
Would you believe that the sun makes the
wind? The sun unevenly heats the different surfaces of the earth. (Land
heats up and cools off faster than water.) As the air over land gets warmer,
the particles spread out, become less dense and rise. The air cools as
it it rises above the land. It then becomes more dense and sinks.
warm air rises, cooler air rushes in to fill in the place of the heated
air. This moving air is the wind. The process of rising and sinking air
is called convection.
The seasons and the
shape of the land, called typography, affect convection.
Wind is called a renewable
energy source because the wind will blow as long as the sun shines.
Renewable energy is made from resources that can be replaced in a short
time. It is also called "clean energy" or "green power."
Energy sources are those that are gone forever once we use them
up. Most are fossil fuels, formed from plants and animals that were buried
millions of years ago. They cannot provide energy forever.
How much renewable energy do we use?
Find out with this multimedia slide
all these Renewable
Energy Fieldtrips with video, for more facts.
The History of Using Wind Power
began to use the power of the wind a long time ago. In 5000 BC, wind powered
sail boats on the Nile River. They developed windmills to grind grain
and pump water. Countries made fleets of sailing ships to trade and explore
In 1888 used the first
windmill generated electricity in Cleveland, Ohio. These windmills started
to be called "wind turbines."
Check out the wind
energy Timeline from the Energy Kid's Page.
Today, wind is used to make electricity,
and wind turbines and wind farms are becoming familiar sights.
How Do Wind Turbines Work?
A wind turbine has 3 parts that we can
see: the tower, the blades and and a box behind the blades, called the nacelle. Wind energy spins the blades
on a wind turbine which generates electricity. It spins something like a pinwheel. The blade is shaped something
like an airplane wing so that air pressure is lower on one side than on
the other. This difference in air pressure creates lift, which forces
the blade to move.
a wind turbine
3 rotating blades of the turbine are connected at the hub. The blades
and hub are called the rotor.The rotor connects to a drive shaft. The
drive shaft goes through a gear transmission box and attaches to a high
speed shaft which turns a generator that makes electricity. (This happens
inside the nacelle). Large turbines have controls that orient the blades
into the wind.
The electricity is sent through transmission
lines and distribution lines to a substation, then on to homes, business,
hospitals and schools.
The Power Grid...interactive
See a wind turbine
in action at the US Department of Energy Web site: Wind
Take the crash
course in wind energy and learn how a wind turbine works. Identify
the parts of a wind turbine.
How tall are wind turbines?
Wind speed increases as the height from the ground increases. Ground friction
and objects on the ground hinder the flow of the wind. More wind speed
generates more electricity. Scientists estimate a 12 percent increase in wind speed with each doubling of elevation.
The large turbine rotors vary from 50 to 90 meters . Small wind turbines
rotors are 8 meters or less and are mounted on towers of 40 meters in
height or less.
fast do the blades rotate?
Between 8-16 mph...and they turn off at about 45-65 mph so they won't
be damaged in storms or high winds. The turbine has a brake that will
keep the blades from turning too fast.
many rotations do the blades make in a minute?
much power can one
wind turbine generate?
The unit of measurement for electricity is called
a watt (W). A kilowatt (KW) is 1000 watts. A million watts is called a megawatt
(MW). A wind turbine can generate from 250 watts to 5 megawatts of electricity,
depending on its size and location. Smaller wind turbines are used for
providing power off the grid: such as
powering a ranch or dairy farm, or remote villages, charging up batteries
on a sailboat, or powering
a school. A megawatt of wind generates about as much electricity as 225 to 300 households use
in a year.
A turbine may run
for 6000 hours a year for 25 years!
a moment to review what you've learned and watch this Wind Power Animation
OF WIND ENERGY
OF WIND ENERGY
| Wind is Free
unpredictable ( wind speed affects amount of energy generated)
a backup system when there is little or no wind
beauty of the area changes
- No toxic emissions, No greenhouse gasses
many wind turbines to replace one traditional non-renewable power
can still be used for farming
areas are expensive, but excellent sources of wind.
be used on land and on sea
be a tourist attraction
affect television reception
reach remote areas, small businesses, used on boats
interference to radio, television, or microwave instruments.
If wind power is used to generate electricity
instead of fossil fuels, you could lighten your ecological footprint. (From the BonnevilleEnvironmental Foundation). According to the PA Wind Map,
if you purchase electricity from non-polluting sources of green power, you
are doing the same as not driving your car 20,000 miles a year. [*]
[*] Conservation Consultants, Inc. Pennsylvania Wind Map. Retrieved August
is a wind farm?
A wind farm, which is also called a wind power plant, is a group of interconnected
wind turbines in the same location. A large wind farm may have of about
36 to about 100 individual wind turbines, and cover hundreds of square miles.
A wind farm may be on land or even, offshore.
does a wind farm work?
do you know where to put a wind farm?
critical factors to consider are: How fast, how often, and how
much reliable wind there is? Are there seasonal variations? Does zoning
allow a wind farm? Is it near transmission lines?
Consult a more complete checklist
energy from the wind rises as a cube of wind speed. In other words, if
wind speed doubles, the power output increases eight times. Choosing the
best location can make a difference.
Geographic location is very important
when determining if there is enough wind. The best places are gaps in
mountains, open plains, tops of rounded hills and, especially, shorlines.
The top 10 states in wind resources are: North Dakota, Texas, Kansas,
South Dakota, Montana, Nebraska, Wyoming, Oklahoma, Minnesota and Iowa. You need an
average wind speed of around 25 km/h.
steps to building a wind farm.
of 30 wind turbines in the United Kingdom's Kentish Flats offshore wind
farm, which produces up to 90 MW.
for Estimating Wind Resources
of the future for wind power are to cheaply produce machines that can produce
power at lower wind speeds!