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.

Blue Apron’s Memorial Day Sale Will Save You $60 On Your First Three Boxes

Scott Eisen/Getty Images
Scott Eisen/Getty Images

If you’ve gone through all the recipes you had bookmarked on your phone and are now on a first-name basis with the folks at the local pizzeria, it might be time to introduce a new wrinkle into your weekly dinner menu. But instead of buying loads of groceries and cookbooks to make your own meal, you can just subscribe to a service like Blue Apron, which will deliver all the ingredients and instructions you need for a unique dinner.

And if you start your subscription before May 26, you can save $20 on each of your first three weekly boxes from the company. That means that whatever plan you choose—two or four meals a week, vegetarian or the Signature plan—you’ll save $60 in total.

With the company’s Signature plan, you’ll get your choice of meat, fish, and Beyond foods, along with options for diabetes-friendly and Weight Watchers-approved dishes. The vegetarian plan loses the meat, but still allows you to choose from a variety of dishes like General Tso's tofu and black bean flautas.

To get your $60 off, head to the Blue Apron website and click “Redeem Offer” at the top of the page to sign up.

At Mental Floss, we only write about the products we love and want to share with our readers, so all products are chosen independently by our editors. Mental Floss has affiliate relationships with certain retailers and may receive a percentage of any sale made from the links on this page. Prices and availability are accurate as of the time of publication.

Why Did Noon Used to Mean 3 p.m.?

3 p.m. is basically noon for people who wake up at 12 p.m.
3 p.m. is basically noon for people who wake up at 12 p.m.
Mckyartstudio/iStock via Getty Images

If you’re a late sleeper, you might find yourself thinking 12 p.m. seems way too early to be considered midday, and the word noon would much better describe, say, 3 p.m. It turns out that ancient Romans would have agreed with you, if only for etymological reasons.

As Reader’s Digest explains, the days in ancient Rome were split into four periods of three hours each. The first hour was at sunrise around 6 a.m.—called prime, for first—followed by 9 a.m. (terce, denoting the third hour), 12 p.m. (sext, for sixth), and 3 p.m. (none, for ninth).

According to Merriam-Webster, Middle and Old English borrowed the time-keeping tradition, along with the Latin word for ninth, which was changed to nōn and eventually noon. Though we’re not sure exactly when or why noon started referring to 12 p.m. instead of 3 p.m., it could have something to do with Christian prayer traditions. In the Bible, Jesus’s crucifixion is said to have taken place at the ninth hour, and that’s when worshippers partook in their second of three daily prayers; the others were in the morning and evening. It’s possible that hungry monks were behind noon’s gradual shift from 3 p.m. to 12 p.m.—since their daily fast didn’t end until after the midday prayer, they had a built-in motive for moving it earlier.

While we didn’t exactly stay true to the original Latin meaning of noon, there’s another important remnant of ancient Rome hiding in the way we tell time today. Romans referred to 12 p.m. as meridiem, for midday, and so do we. A.M. is an abbreviation for ante meridiem, or before midday, and P.M. means post meridiem, or after midday.

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