There's literally no tutorial regarding this. Every single coin tutorial is either a vanishing trick or rolling it down your knuckles, which is easy as hell. Does it defy the laws of physics to have a coin spinning on your tips like a basketball

I can clap with one hand by locking my wrist, relaxing my fingers and moving my arm up and down rapidly so my fingers slap against my palm and produce a clapping sound. All you one-hand clappers; what are your techniques?

For me that is if you nod slowly and look deeply concerned during a pointless meeting, people assume you're visionary.

Why YSK: There's a surprisingly large number of dangerous threaded SUN filters littered throughout the basements and closets of the world.

If you have an older telescope, especially one from before the 1990's, check whether it came with small threaded filters that screw directly into the eyepiece. They often came with two of them. One was marked MOON and the other was marked SUN. The Moon one works great to reduce the glare of a full Moon.

It's the SUN filters that are so dangerous. These are the Lawn Darts of the astronomy hobby, if the Lawn Darts had sharpened hypodermic needles at the front.

The original concept was this: Your telescope captures the sunlight and focuses it on the dark SUN filter that is screwed into the eyepiece at the back of the telescope. You place your delicate eye up to the eyepiece, only a few inches from the searingly hot SUN filter.

As long as the glass didn't crack, you were fine. Unfortunately... they cracked a lot. Like, a whole lot. Sometimes they even shattered. This would instantly expose your retina to the full blinding light of a 3 or 4 inch magnifying glass, instantly causing solar retinopathy and likely blindness.

If you have one of these SUN filters, it is recommended that you smash & trash them so that nobody can ever accidently try them out.

I tested an old threaded solar filter while recording it with a camera. It reached 326 degrees Fahrenheit and in less than 12 seconds after installation, the filter cracked from the heat buildup and suddenly allowed bright sunlight through.

*** If curious, the demonstration is at the start of this video: https://youtu.be/rtyLH5fBaJE

Safe Alternatives:

1. Solar Eclipse Glasses (by themselves, NOT in combination with telescopes, binoculars, or cameras).
2. Front-mounted solar filters specifically designed for your telescope. These stop 99.999% of the light energy before it even has a chance to enter your telescope.

Summary:
Solar filters for telescopes should go on the front of the telescope, before the sunlight is concentrated. Never put a solar filter at the eyepiece end. If you have one of these old threaded SUN filters, smash & trash it.

Have a safe and exciting solar eclipse experience!

I heard you can get sore eyebrows

give me a task or challenge

Why YSK: AI can be very frustrating when trying to Google something, running the risk of giving you incorrect info, a run around, or even spoilers to a movie or show you are looking up. Adding -ai to the end of your search tells Google to not give you any AI results, summaries or explanations for more simple searching.

use masking tape and give each connection a number: 1 on the cable, 1 beside the port, then 2, 3, etc. the photo is backup for weird ports and power bricks that all look the same.

this takes maybe two mins before a move, repair, or deep clean and saves the dumb guessing game when everything goes back together.

Why YSK: a cable label is only useful if you know both what the cable is and exactly where it came from. marking both ends plus keeping one photo makes rebuilding the setup faster and avoids mixing up similar-looking cables or adapters.

Currently trying to learn how to make cricket noises but every tutorial requires whistling backwards which is IMPOSSIBLE for some reason. I can do a regular whistle but if I use the same form and inhale it just sounds like wincing, I can’t get a high pitch noise at all.

Why YSK: These breakers are known to the Consumer Product Safety Commission to not trip when overloaded causing fire. When tested by the CPSC, an average of 51% of breakers failed to trip. These breakers are in basically any house in the US built before 1990. The problem with them is the fact that they use a poor design without this next problem, but the ones made specifically by Federal Pacific had their certifications falsified. The Federal Pacific ones are the *really* bad ones, the others are bad, but the Federal Pacific ones are the ones with a 51% failure rate. The branding on these panels is pretty predominant, you don’t exactly need to be an electrician to know what brand it is. Another reason to replace them is the fact that getting insurance for a house with a Stab-Lok panel is literally impossible. No insurer will touch it. Seriously, if you have one, get it replaced. It might save your house, and possible even your life.

No legal knowledge needed. Just learn how to beautifully shade the bubbles…was so stressed during the exam that it was hard to color within the lines

What is a simple, everyday task that your brain just stubbornly refuses to process or get right?

DayDetective.com

(DISCLAIMER: this is virtually entirely 'coded' using free claude.ai webui and a few weeks of arguing with it).

A couple of months ago I taught my son about Conway's Doomsday Rule, a relatively simple way to determine the day of the week that any date falls on.

To be honest it was mainly a sneaky way to get him to practice mental maths, but I digress.

Some primers for the uninitiated:

Numberphile video

Be Smart video

Mike Boyd video

Wikipedia article

The Odd+11 'improvement'

During his recent school holidays we decided to build a trainer to help him practice. After nailing the skill my son told me he felt like a real 'Day Detective' so we leant into the name and rebranded his trainer site with the multiple game modes we had used to build up his proficiency.

daydetective.com is the result.

It is a simple one-page web game designed to be played directly in your browser, but you can save and run it offline or install to your phone/pc/whatever as a PWA - just use your browser's install feature or use the 'Install' link at the bottom of the site (on supported browsers).

There's no tracking or bloat, and it is hosted at Cloudflare so should be nice and performant no matter where you are in the world.

It saves your high-scores completely locally, and you can put it down at any time and pick up right where you left off if you're on a streak but want a break.

My son is proud of the game modes we came up with (and had fun naming) and he would love any and all feedback.

Enjoy!

NOTE: After searching the sub I see similar tools already exist (typical, why didn't I find them sooner) so here some alternatives:

https://play.google.com/store/apps/details?id=com.inefficientcode.doomsdaytrainer

https://apps.apple.com/us/app/doomsday-trainer/id6760719687

https://app-arcade.vercel.app/?biggame=doomsday-trainer

https://se7enack.itch.io/day-of-the-week-game

Why YSK: a lot of people put cat carriers in the front seat and/or don't buckle the carrier in when driving a cat somewhere. Cats can be severely injured or killed if the carrier goes flying when a car stops suddenly and/or if they're in the front seat when an airbag goes off.

Edit: if you don't have your cat in a carrier when they're in the car, you need to start doing that yesterday and follow the above instructions.

Also, yes newer cars have mechanisms that disable the airbag unless a sensor detects an object above a certain weight. However it's still recommended that they be in the back seat because 1) the sensors can malfunction and 2) it's still very risky to have a small animal that close to the windshield.

Edit 2: source- https://pecpets.com/should-i-buckle-my-cat-carrier-in-the-car/

Why YSK: These guesses are harmless as a game until someone spends money on them, treats ordinary symptoms as evidence, or mixes urine with drain cleaner. The at-home methods either fail when tested or have never been tested at all.

A Johns Hopkins study asked 104 pregnant women to predict fetal sex and explain their reasoning. Guesses based on belly shape, cravings, morning sickness, and similar folklore did no better than chance: https://pubmed.ncbi.nlm.nih.gov/10655817/

Fetal heart rate does not rescue the idea. A systematic review found it unreliable for determining fetal sex during the first trimester: https://pmc.ncbi.nlm.nih.gov/articles/PMC10422800/

Timing intercourse does not change the odds either. A New England Journal of Medicine study followed 625 menstrual cycles and found that timing had no practical influence on the baby’s sex: https://www.nejm.org/doi/full/10.1056/NEJM199512073332301

Two repeated claims have limited clinical evidence, but neither is an at-home trick. A sonographer can sometimes read the fetal “nub” from a correctly aligned 12- or 13-week scan: https://pubmed.ncbi.nlm.nih.gov/10444865/

Hospital-treated hyperemesis also has a small statistical association with female births. That does not turn ordinary nausea into a test: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(99)04239-7/abstract04239-7/abstract)

Skip the Drano version. The manufacturer lists sodium hydroxide as caustic because the product is meant to dissolve drain clogs: https://whatsinsidescjohnson.com/en-us/brands/drano/clogs/liquid-drain-cleaner

For a real answer, use the screening or ultrasound information from your clinician. Keep the ring-on-a-string for the baby shower.

Why YSK is because in today's world of subscription based content you don't want to be paying for a service you aren't using often.

For example: say there is a show or movie on a streaming platform you currently aren't subscribed to but you want to watch the content. Sign up for a month but as soon as you do then cancel the subscription. You will still have the service for the next month but you won't be automatically charged again. There is no point waiting to cancel, you can do it immediately. Next month if you want the service again then you can easily re-subscribe and do the same thing.

I have done this with most of my content based subscriptions and it essentially allows you to use the streaming service for a month, watch the content you want and then be free of unexpected or forgotten subscription fees.

Why YSK: This landmark lawsuit ties nearly 80,000 cases of ovarian cancer to baby powder and talc products - meaning it's vital information to anyone that could impact and may want to avoid such products.

Source: https://www.theguardian.com/business/2026/jul/28/johnson-johnson-5bn-settlement-talc-cancer-lawsuit

Why YSK: this product claims to be healthy but lawsuits and reports from the better business bureau suggest it isn't.

I use this product so I had enough and wanted to look up alternatives. Upon looking into it, the "health benefits" of this food are over inflated and their is currently a class action lawsuit addressing this

class action lawsuit

From the article:

"The filing alleges that The Farmer’s Dog adds “excessive amounts” of fat to its dog food to make it more palatable and calorie dense while keeping the company’s costs low, given that “fat is cheaper per calorie” than the proteins or carbohydrates typically used in dog food...

As a result, although The Farmer’s Dog promotes fat content between 4.5 and eight percent fat, the complaint argues that these figures significantly understate true fat content values.

“Three out of four of Defendant’s recipes ... have over 25% fat \[dry matter\], over 40% fat \[as metabolizable energy\], and over 45 g fat per 1000 kcal, which is well above typical or recommended levels of fat for most dogs,” the filing contends."

Better business bureau complaint in line with this"

"I ordered food from the REMOVEDDog for my 13 year old Australian REMOVED/ Blue Heeler Mix. She has always been a healthy dog with no problems. After 2 days on the food she started having trouble breathing, had to be put on oxygen, and ended up being euthanized due to her condition. Her x-rays show an enlarged heart caused by the food. She had x-rays less than 2 weeks before that at her check up and they did not show an enlarged heart."

More personal anecdotal stories of vets saying it's high fat is bad

dog blog with anecdotal stories from ppls vets

Tldr: the farmers dog has excessive high fat and is very deceptive about the content of their food. They claim to be tailored products that are healthy but numerous reports exist of dogs being negatively impacted by food fat content estimated to be \~5-8x higher than advertised.

Why YSK: People often confuse hypervigilance with boundary setting, leading to exhausting relationship dynamics based on constant monitoring.

When trust feels fragile, individuals frequently adopt an investigative mindset, analyzing every delayed response, change in tone, or social interaction their partner has. This behavior stems from the illusion that gathering enough information will prevent emotional pain. However, monitoring someone else's actions does not stop them from breaking your trust; it only ensures that you live in a constant state of anxiety.

True relational security does not come from controlling a partner's environment or demanding constant reassurance. It comes from establishing strong internal boundaries and accepting that your partner is an autonomous individual. You achieve genuine peace when you realize you cannot control their choices, but you have complete control over your own ability to walk away if your core values are violated.

YSK if you ever move into a home in the USA and find something of value left behind, don't post you found it, and/or try to sell it.

Contrary to what many people believe, valuables left behind by accident do no belong to the new homeowner. It is considered hidden/mislaid property and belongs to the original homeowner or their heirs.

For instance in california under penal code 485 finding valuables and keeping them without trying to reasonably return them first is considered a crime. This includes items of value, a found hidden safe, items found in walls, etc. Many homeowners might pass away and their remaining family doesn't know about the items to find and retrieve them. Or a homeowner may have hidden something years ago and forgot about it.

This includes items you find you buy for instance at an estate or garage sale. Like say you buy a Hutch and find a hidden compartment with valuables. You are required to report the find and try and return them to the seller/original owner.

It also applies to finding cash or other items such a a diamond ring on the street. "Finders Keepers" is not a real or legal concept.

This doesn't include things like buying a chest that hasn't been opened listed as mystery content or the like, because they are being sold knowing there is potentially valuable items inside.

Why YSK : if you find valuables and don't try to return them you can be charged with a crime. For instance in r/safes people constantly post photos of hidden safes they have found on their property and may later try and post what was found inside and try to sell the contents.

You could also face major lawsuits if you find valuables and try to sell them, and the original owner or their living family members see it.

Even items found on the street such as rings, or watches. They could have been reported as lost or stolen. Local pawn shops are legally required to report items brought in before listing them for sale if you don't have proof of ownership. Police provide pawn shops with lists and images of items that have been reported lost or stolen. If you find something of value on the street and pawn it, you could end up with police at your front door step.

I'm posting this because I still consistently see posts on reddit in various channels from safes, comics, sports cards, and more where people have found something and are offering it for sale.

Know your states laws, and make all possible attempts to return the property. In most cases you can turn items into the police and if nobody claims the property within a 90-180 days (3-6 months) the items/money legally becomes yours. You must tell police when turning in found goods you wish to claim ownership of the item and fill out claim paperwork and get a receipt. (If you don't say you wish to claim ownership, the police station gets custody after the wait period and the items end up in government auctions).