How Do Water Towers Work?

iStock
iStock

As infrastructure goes, water towers are pretty picturesque. Some people turn them into houses once the city no longer needs them. The designers at Pop Chart Lab have created a visual ode to New York City’s water tower taxonomy. But why exactly do we need to store our water hundreds of feet above the city?

Most water towers are pretty simple machines. Clean, treated water is pumped up into the tower, where it’s stored in a large tank that might hold a million or so gallons—enough water to run that particular city for a day. When the region needs water, water pumps utilize the pull of gravity to provide high water pressure. Because they work with gravity, they have to be taller than the buildings they’re providing water to in order to reach the highest floors. Each additional foot of height in a water tower increases water pressure by .43 pounds per square inch.

Here's a basic diagram of what a water tower system looks like:

Image Credit: Jonathan Cretton via Wikimedia Commons // Public Domain

Keeping water high off the ground plays another important role for a city infrastructure. It allows regions to use smaller water pumps. In general, water demand for a city fluctuates throughout the day. Lots of folks are taking showers before work and school, but fewer people are running a lot of water at 3 a.m. Without a water tower, the municipality would have to buy a water pump big and powerful enough to keep up with peak demand in the mornings, which would then largely go to waste during less busy parts of the day for water usage (plus incur extra costs). Instead, municipalities can buy a pump just large enough to satisfy the region’s average water demand for the day, and let the power of the water tower take over during the times with demand that exceeds the pump’s capabilities. When water demand goes down at night, the pump can replace the water in the tower. Also, if the power goes out and the city’s water pumps fail, the water tower can keep water running smoothly for at least 24 hours.

Go inside a water tower in Edmond, Oklahoma:

And in Bloomington, Minnesota:

Look at that tank!

Screenshot via YouTube

And here's a 1-million-gallon water tank getting cleaned:

While water towers generally seem like the product of a bygone era, they’re still very much relevant today. The Louisville Water Tower in Kentucky, built in 1860, is the oldest surviving water tower in the country, and it's still in use. In New York City, millions of people still get water from water towers, though it's one of the last large cities to rely on the system. Stored on top of tall buildings, these water towers provide the pressure for water to flow even if the electricity goes off (especially during a fire).

And, of course, one cannot discount the cultural importance of the water tower:

Image Credit: Jonathunder via Wikimedia Commons // CC BY-SA 3.0

Every city deserves a skyscraper-sized civic monument to its favorite crop. Or beverage decanter.

What is a Polar Vortex?

Edward Stojakovic, Flickr // CC BY 2.0
Edward Stojakovic, Flickr // CC BY 2.0

If you’ve turned on the news or stepped outside lately, you're familiar with the record-breaking cold that is blanketing a lot of North America. According to The Washington Post, a mass of bone-chilling air over Canada—a polar vortex—split into three parts at the beginning of 2019, and one is making its way to the eastern U.S. Polar vortexes can push frigid air straight from the arctic tundra into more temperate regions. But just what is this weather phenomenon?

How does a polar vortex form?

Polar vortexes are basically arctic hurricanes or cyclones. NASA defines them as “a whirling and persistent large area of low pressure, found typically over both North and South poles.” A winter phenomenon, vortexes develop as the sun sets over the pole and temperatures cool, and occur in the middle and upper troposphere and the stratosphere (roughly, between six and 31 miles above the Earth’s surface).

Where will a polar vortex hit?

In the Northern Hemisphere, the vortexes move in a counterclockwise direction. Typically, they dip down over Canada, but according to NBC News, polar vortexes can move into the contiguous U.S. due to warm weather over Greenland or Alaska—which forces denser cold air south—or other weather patterns.

Polar vortexes aren't rare—in fact, arctic winds do sometimes dip down into the eastern U.S.—but sometimes the sheer size of the area affected is much greater than normal.

How cold is a polar vortex?

So cold that frozen sharks have been known to wash up on Cape Cod beaches. So cold that animal keepers at the Calgary Zoo in Alberta, Canada once decided to bring its group of king penguins indoors for warmth (the species lives on islands north of Antarctica and the birds aren't used to extreme cold.) Even parts of Alabama and other regions in the Deep South have seen single-digit temperatures and wind chills below zero.

But thankfully, this type of arctic freeze doesn't stick around forever: Temperatures will gradually warm up.

In What Field Was Dr. Martin Luther King, Jr. a Doctor?

Express Newspapers/Getty Images
Express Newspapers/Getty Images

Martin Luther King, Jr. earned a doctorate in systematic theology from Boston University in 1955. He’d previously earned a Bachelor of Arts from Morehouse College and a Bachelor of Divinity from Crozer Theological Seminary. His dissertation, “A Comparison of the Conception of God in the Thinking of Paul Tillich and Henry Nelson Wieman,” examined the two religious philosophers’ views of God in comparison to each other, and to King’s own concept of a "knowable and personal" God.

Some three decades after he earned his doctorate, in 1989, archivists working with The Martin Luther King Papers Project discovered that King’s dissertation suffered from what they called a “problematic use of sources.” King, they learned, had taken a large amount of material verbatim from other scholars and sources and used it in his work without full or proper attribution, and sometimes no attribution at all.

In 1991, a Boston University investigatory committee concluded that King had indeed plagiarized parts of his dissertation, but found that it was “impractical to reach, on the available evidence, any conclusions about Dr. King's reasons for failing to attribute some, but not all, of his sources.” That is, it could have been anything from malicious intent to simple forgetfulness—no one can determine for sure today. They did not recommend a posthumous revocation of his degree, but instead suggested that a letter be attached to the dissertation in the university library noting the passages lacked quotations and citations.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

This article was originally published in 2013.

SECTIONS

arrow
LIVE SMARTER