A Simple Trick For Figuring Out the Day of the Week For Any Given Date

iStock.com/Tevarak
iStock.com/Tevarak

People typically remember anniversaries in terms of dates and years, not days of the week. If you can’t remember whether you got married on a Saturday or Sunday, or don't know which day of the week you were born on, there’s a simple arithmetic-based math trick to help you figure out sans calendar, according to It's Okay To Be Smart host Joe Hanson.

Mathematician John Conway invented the so-called Doomsday Algorithm to calculate the day of the week for any date in history. It hinges on several sets of rules, including that a handful of certain dates always share the same day of the week, no matter what year it is. (Example: April 4, June 6, August 8, October 10, December 12, and the last day of February all fall on a Wednesday in 2018.) Using this day—called an “anchor day”—among other instructions, you can figure out, step by step, the very day of the week you’re searching for.

Learn more about the Doomsday Algorithm in the video below (and if it’s still stumping you, check out It’s OK to Be Smart’s handy cheat sheet here).

Watch 32,000 Dominos Fall in an Extremely Satisfying Way

iStock/Khongtham
iStock/Khongtham

Lily Hevesh, known as Hevesh5 on YouTube, has achieved viral fame many times over with her ambitious domino videos. She's shown us dominos falling up a flight of stairs, dominoes toppling in a three-part spiral, and dominos collapsing in a continuous chain of record-breaking length. To make the video below, she collaborated with six fellow domino artists and set up an elaborate, freestyle design that leads to a domino fall that's incredibly satisfying to watch.

According to the video's description, this was the biggest project Hevesh and her collaborators built during a domino event she hosted earlier in 2019. The artists—which in addition to Hevesh5, included YouTube creators NC Domino, StickTrickDominoDude, Chris Wright, Jaytar42, jackofallspades98, and SmileyPeaceFun—gave themselves three-and-a-half days to set up 32,000 dominos using the most oddly satisfying domino tricks they knew.

Hevesh writes in the video description: "Everything in this setup (besides one field) was freestyled so we did not draw out a detailed floor plan. All we had was a list of satisfying domino project ideas that we built and connected on the spot."

In less than four minutes, the video showcases pyramids, spirals, and artistic patterns, all made from toppling plastic bricks. Whether or not you can name all the domino tricks that are featured, seeing them in action is mesmerizing. You can watch the full video below, and then subscribe to Hevesh5 for more domino creations.

Watch What Happens When Mannequins Misuse Fireworks

martaland/iStock via Getty Images
martaland/iStock via Getty Images

With the Fourth of July comes all the requisite warnings about fireworks safety. These sometimes-legal (check your local laws) explosives can provide a rapturous end to holiday festivities and events. They can also end in emergency room bills and tragedy.

This week, the U.S. Consumer Product Safety Commission (CPSC) set up a demonstration to illustrate how quickly the mishandling of fireworks can go wrong, and it looks like something out of the opening sequence in Saving Private Ryan:

These mannequins violate a number of safe practices for fireworks, including pointing them directly at the heads of friends and peering into the mouth of a mortar tube. There’s also a caution about trying to make fireworks at home, which can have roof-blasting consequences.

While the dummies in the video exhibit poor judgment, their sacrifice might help humans avoid a similar fate. According to the CPSC, 280 people end up in the emergency room per day in the month around July 4 as a result of fireworks-related mishaps. Hands and fingers make up most of the injuries (28 percent), with legs (24 percent) and eyes (19 percent) also being vulnerable. Nearly half (44 percent) of injuries are burns. All told, 12,900 people were treated for fireworks wounds in 2017 [PDF].

To avoid injury, it’s best to avoid fireworks that come wrapped in brown paper, since those are typically made for professional use only. It’s also a good idea to keep children away from sparklers, which can burn in excess of 2000 degrees Fahrenheit. (If you would not hand your child a blowtorch, it’s probably not a good idea to hand them a sparkler.) If you must light a firework, do it and then get as far away from it as possible.

The CPSC has capped consumer fireworks so that they contain no more than 50 milligrams of powder. More formidable explosives, like cherry bombs and M-80s, have been banned by the federal government. Most states allow at least some fireworks to be sold and used.

If the mannequins really wanted protection from accidents, they should have moved to Massachusetts; it’s the only state where all consumer fireworks are banned.

[h/t CBS Denver]

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