From Snails to Whales: The direction of rotation of a draining sink is determined by the location on northern or southern hemisphere?

Friday, July 11, 2014

The direction of rotation of a draining sink is determined by the location on northern or southern hemisphere?

Before talking about the subject, let me introduce myself first. I am from Taiwan and this is my first time to Boston. I received my MBA degree from National Taiwan University and have worked in financial industry for 17 years. I started a venture capital firm with my colleague 3 years ago. Because I never had a chance to study abroad, I always dreamed I could spend some time as a student in USA. Now my dream come true. It is my honor to learn from Professor Berman and get to make new friends!
About today's field trip to "Lady's restroom" to observe the direction of rotation of a draining sink, there were quite many different observations from everyone in the class. For my observation, I saw the direction is clockwise. To make sure it is right , I made 4 more experiments (one in my bath room sink , the other tree in kitchen sink)after I came home. To my surprise, there are two clockwise and two counterclockwise rotations. I start to assume the direction of rotation of a draining sink is not determined by the location on earth but by another factors(e.g. size of sink, water level) .
To confirm my assumption, I make some research on internet. The three sources I looked up all lead to same conclusion " The direction of a draining sink is determined by the way it is filled or by vortices introduced while washing". The Coriolis Effect is too small to be relevant when you pull the plug of the sink!
Source:
1.http://www.ems.psu.edu/~fraser/Bad/BadCoriolis.html
2.http://math.ucr.edu/home/baez/physics/General/bathtub.html
3.http://www.loc.gov/rr/scitech/mysteries/coriolis.html

No comments:

From Snails to Whales

Welcome to Snails to Whales, Bruce Berman's blog focused on both the little and the big things that make Boston Harbor such an interesting and extraordinary place to live, work and play.

With 50 miles of protected water, four sheltered bays, seven river systems, 34 islands and a nine-foot average tide, Boston Harbor is one of the most diverse urban ecosystems in America.

This blog focuses on the flora and fauna of Boston Harbor and Massachusetts Bay - on the beach, the shore, and the harbor islands, and in the cleaner waters of Boston Harbor and Mass Bay - including this ecosystems most important species - people.

During the summer, it is also a place for my Boston University Students and my colleagues at Save the Harbor / Save the Bay to share their work and experiences.

Where I am coming from...

Love that clean(er) water
Learning about the Boston Harbor Cleanup from the waterway’s eyes, ears, and mouthpiece

By Brian Fitzgerald, BU Bridge

On Georges Island, Bruce Berman talks with his students about the history of the Boston Harbor Cleanup,
which is largely complete. Photo by Vernon Doucette

Bruce Berman, aboard a ferry from Boston’s Long Wharf to Georges Island, poses a question to his students: “How clean is clean enough?”

He’s talking about the water below.

It’s a brilliant July day, with the smell of salt spray in the air. The sky is clear, and so is the ocean. But there was a time when Boston Harbor wasn’t so clean, when the stench of sewage assaulted the nostrils of anyone who went near it.

Berman is the communications director for Save the Harbor/Save the Bay, a public-interest environmental advocacy organization whose mission is to help restore and protect the harbor and Massachusetts Bay. He also teaches a Metropolitan College summer course called Politics, Public Relations, and Public Policy: The Boston Harbor Cleanup.

“The Boston Harbor Cleanup is an amazing success story, and I just love to share it with students,” says Berman, noting that the harbor’s “bad old days” weren’t that long ago. Those were the days when untreated human waste, syringes, condoms, and tampon applicators routinely washed ashore. The antiquated sewage treatment plants on Deer Island and Nut Island were so poorly designed and maintained that they flooded during even mild rainstorms, sending millions of gallons of untreated waste directly into the harbor.

Since then, bacteria counts in the water have decreased by more than two-thirds. Now the harbor teems with plants and animals, and people can legally dig for clams on Carson Beach in South Boston, which was unheard of in the 1980s.

“It was one of the filthiest harbors in America, and now it’s one of the cleanest,” says Berman. “What I’m trying to impress upon students is how this incredible comeback occurred, and how business, advocacy groups, environmentalists, and government can affect the outcome of large projects such as the Boston Harbor Cleanup through negotiation.”

Paradise regained

Berman points to the left as the boat cruises by the cleanup’s centerpiece: the gargantuan white egglike tanks of the Deer Island waste treatment plant, which in 1995 replaced the antiquated facility. The plant treats an average of 350 million gallons of sewage a day.

“And what comes out of the Deer Island treatment plant?” he asks. Berman, his booming baritone competing with the roar of planes taking off from Logan Airport, has a habit of putting students on the spot to see if they’re paying attention.

“The outfall pipe,” say several simultaneously. “Treated water,” chime in a few more.

“That’s right,” he says with a smile. “The plant separates the solid and liquid waste, and it pumps the treated water through the 9.5-mile outfall pipe, which empties into Massachusetts Bay. The resulting sludge is converted to high-grade fertilizer.”

Now Berman returns to his original question: “How clean is clean enough?” There’s no quick and clear answer to this one. “It’s a question that at the end of the day the federal courts had to decide.”

In 1985, a landmark federal court case required that the harbor’s beaches be made swimmable and fishable by 2000. Save the Harbor/Save the Bay was formed the next year to raise public awareness of the $4.5 billion Boston Harbor Cleanup. Sewer ratepayers in the 43 cities and towns financing the project cried foul over the prospect of astronomically rising bills, but because of the determination of environmental advocacy groups such as Berman’s, the cleanup was largely completed on schedule.

Berman says it isn’t finished, however. There are still frequent beach closures because the counts of Enterococcus bacteria exceed the federal and state standard for swimming. The culprit: filthy storm water and sewage, much of it from leaky pipes and illegal hookups emptying into storm sewers, and then into the harbor.

“So is the harbor clean enough,” the Springfield native asks his students, “when you can’t swim in it one out of five days in the summer?”

Work to be done

Berman and his class look out from Georges Island to Gallops Island (left) and the white tanks of the waste treatment plant on Deer Island (right). Photo by Vernon Doucette

This summer the state approved one of the last parts of the cleanup: the construction, by 2011, of a 2.1-mile tunnel near the Dorchester and South Boston shorelines that will hold sewage and storm water during bad weather. It then will be pumped to Deer Island for treatment.

Berman is ecstatic over this development, the result of “tireless negotiation and consensus-building,” he says. “After 2011, we’re looking at beach closings once every five years, when there is a major storm, instead of once every five days.”

But he is not about to let his guard down. To say that he is a man obsessed with the harbor cleanup would be an understatement. Berman is also Save the Harbor/Save the Bay’s “Baywatcher,” and he lives on his 40-foot trawler Verandah. Polluters beware: if you’re discharging oil or sewage into Boston Harbor, the Baywatcher just might be watching.

He is quick to point out that his zealotry is not just on behalf of the harbor’s flora and fauna. “The harbor is for everyone,” he says. “If you’re from a working class or poor family in Boston, and you can’t afford a Cape Cod getaway in the summer, a clean harbor is important. The same is true if you’re a tourist vacationing in Boston or you happen to live in a pricey waterfront condo.”

Accordingly, Berman, who was a political consultant and contributing editor to the Phoenix newspaper before joining Save the Harbor/Save the Bay nearly 10 years ago, also teaches his students about the harbor’s role in the city’s economy. He points out that in the early 1990s, just a few ferries cruised the harbor’s waters. Today, more than 100,000 people visit its islands each summer, discovering their ecological and historic treasures.

“The best way to protect the harbor cleanup,” Berman tells his students, “is to make sure that the public has access to the resources and can see a return on its investment.”

Trevor Kosmolsick (MET’05) has lived in Boston for seven years, but until taking Berman’s course, he had never been to the waterfront. “I’ve also wanted to go camping in the area, but I never knew that you could camp on a few of the islands,” he says. “Bruce Berman is not only a great professor, but the ultimate tour guide.”

He also backs up his words with actions. Sometimes he takes off his shirt and dives in the water to demonstrate to passing boaters that it’s safe to swim. To show people on ferries that fishing is safe, he’s been known to grab one of the bluefish or striped bass he’s caught and (very carefully) plant a wet kiss on it.

“What I want everyone to understand is that investment in the environment really does pay off,” says Berman. “We’re willing to pay for a clean Boston Harbor, so we should enjoy it.”

From Snails to Whales

Friday, July 11, 2014

The direction of rotation of a draining sink is determined by the location on northern or southern hemisphere?

No comments:

Nature Blog Network

My Favorite Nature Blogs