The class went on a trip to MOS museum to study wind,  solar energy and investigate the exhibit. What captivated me at the beginning of exploring the museum was the electricity section since I’m an electrical engineering student. Fortunately, the timing was perfect for me to attend the breathtaking presentation of the electricity exhibit. As I walked into the section there was a guide explaining the exhibit to the audience. The guide introduced Nikola Tesla’s invention.  His invention of the alternating current motor set the stage for the power and lighting systems now used every day around the world. We also were introduced to Faraday’s cage shown in the picture below.

We were shocked when the guide was absolutely confident as walking into the cage that nothing would happen to him. Surprisingly, not even a single lighting went into the cage. As he explained, it is because the cage’s wall is conductive so that when the electricity hit it, it will be absorbed by the cage’s wall and prevented from going inside. So, the guide proved that staying in the car while a lightning storm is actually safe. Another experiment that dazzled my eyes, there were two adjacent conductive poles with ring shaped tops. When the guide applied high electricity to the poles, the high electricity could overcome the insulating air so we could see it flowing from pole to pole like lightning. As the guide changed the value of current, certain musical tones were produced. This happens when current is being released pushing the air around it, so our eardrums receive these what we can call waves of pushed air making us hear different tones according to the amount of the released current.

Wind exhibit

The first aspect I explored in this section was the different types of wind turbines and their efficiency. Below is a picture of turbine types that were shown.

 

And below is a table of the differences;

Turbine	Rotor Diameter	Tower Height	Weight	Max Rated Power	Annual Max Power	# of 15-watt light bulb
Windspire	4 ft	no tower;30 ft tall	600 lbs	1.2 kw	10,512 kwh	12
Southwest Skystream 3.7	12 ft	33 ft	170 lbs	1.9 kw	16,644 kwh	19
Swift Rooftop Wind Energy System	7 ft	9 ft	209 lbs	1.5 kw	13,140 kwh	15
Proven 6	18 ft	30 ft	2,769 lbs	6 kw	52,560 kwh	60
Architectural Wind: AVX1000	6 ft	no tower;6 ft tall	130 lbs	1 kw	8,760 kwh	10

It is clear that the longer the turbine and the bigger the blades the more electricity we can generate as explained mathematically below.

P=½ρAV³

P= power in watts  ρ = The air density (1.2kg/m³ @ sea level and 20° C

A = The swept area of the turbine blades (m² square meters) 

V = wind speed ( meters per second)

Power of gears also plays an important role in generating electricity. There was an interlocking gears model for us to see how they fit together to form part of the gearbox inside the nacelle of a wind turbine as shown below.

 

It is predictable that the right wheel doesn’t require a great force to make it spin unlike the left wheel. If an equal external forces are applied to both wheels and then removed, the left wheels will keep moving for a much longer time than the right wheel. In other words, the deceleration of the left wheels is smaller than the one of the right wheel. That is because the external force that has been applied to the left wheels will be generated even more from the first wheel to the other.

Environmental impacts of wind turbines

While wind turbines have a much smaller impact that fossil fuels, they can affect the environment in different ways such as land use and birds deaths.

Land use

Although each turbine takes up very little space, wind farms require roads and electric substations. Careful selection of locations can minimize the impact. Smaller, building-mounted turbines are also an alternative. Offshore turbines use no land, but must avoid known shipping channels.

Bird deaths

Birds and bats can die in collision with turbines. Power lines, glass-covered skyscrapers, and cats can kill just as many. About 40,000 birds are killed by wind turbines every year, compared with 2,000,000 birds killed from oil spills. Careful consideration in placing wind turbines can minimize this number.

http://www.ask.com/question/what-is-nikola-tesla-famous-for

http://www.windgenkits.com/faq.htm

http://www.mos.org/