Noise Pollution?!

In October, I learned of a cool opportunity with NASA that culminates in a summer week-long trip to the Johnson Space Center: the High School Aerospace Scholars program. I promptly applied and waited with bated breath. Upon learning of my acceptance, I had a brief moment of celebration until I realized I would need to complete extra online assignments through spring. ~~Conclude backstory~~

Through an online course I am taking on aerospace topics, I learned of noise pollution and the ways NASA is addressing it. Noise always surrounds me, and I have never thought of it as pollution. However, loud sounds from airports, traffic, and construction sites are real issues that causes hearing damage to many. 

My course primarily addressed the airport aspect of the issue, and offered a quieter alternative to the traditional tube-and-wing design of aircraft that is used on practically every aircraft today. Its use for decades stems from its relative simplicity, efficiency, and ease of design. However, NASA researchers have developed a new design, the blended-wing-body (BWB) design that promises better efficiency, lower noise production, and increased safety. This design works by creating more lift with less drag with its combined body and wing, resulting in less fuel burn and less noise production.

This development could prove to alleviate headaches for residents near airports, as well as significantly boosting the cool-ness factor of flying.

Sources:

NASA 360. "NASA Aviation Technology." YouTube. YouTube, 04 Feb. 2015. Web. 10 Dec. 2015.

How to get rid of ... sound?!

In the spirit of the holiday season, I was browsing those great Cyber Monday deals the weekend of Black Friday and came across a great looking pair of fancy "noise-cancelling" headphones.

http://www.amazon.com/Bose-QuietComfort-Acoustic-Cancelling-Headphones/dp/B00M1NEUA0/ref=sr_1_1?ie=UTF8&qid=1449696020&sr=8-1-spons&keywords=noise+cancelling+headphones&psc=1

I've tried noise-cancellation before at various stores and can attest to their effectiveness. However, how does this technology work? You can't just swat sound waves out of the air. Turns out, you actually use sound's nature as a wave against them!

Let me ask you a simple question: What is sinΘ - sinΘ ? You don't need to know trigonometry or calculus to know that anything minus itself is zero. When talking about noise cancellation, that zero means a quiet listening experience!

Waves can be mathematically represented using sine or cosine, and when two waves meet, the result is their sum. Say that one wave can be represented with sinΘ and another wave is represented by
-sinΘ. When they meet, the result is sinΘ + (-sinΘ) = 0. This process, called complete destructive interference, results in both waves cancelling each other out and a heightened enjoyment of the sounds you actually want to hear!

Sources:
Harris, William. "How Noise-canceling Headphones Work." HowStuffWorks. N.p., 14 Feb. 2007. Web. 10 Dec. 2015.