What are /r/educationalgifs' favorite Products & Services?

From 3.5 billion Reddit comments

Looks like a clear version of these bead things for kids: https://smile.amazon.com/Rainbow-Growing-Tactile-Sensory-Decoration/dp/B071W18C3X?sa-no-redirect=1

These things are fucking fun btw, bought them for watering plants but they're great to play with too.

A sunrise alarm clock really helped me, especially in winter. (I still have a back-up alarm on my phone though.) It's a light that gradually gets brighter over the course of a half-hour and then it sounds an audible alarm at the end. The light's enough to get me awake enough to realize that my alarm is going off.

Here you go!

Olive Oil Nablus Soap (1 count) https://www.amazon.com/dp/B00537QFK4/ref=cm_sw_r_cp_api_i_lsDpDbXBY4PNP

If that link doesnt work (because I’m on mobile), just search Nablus soap on amazon

Have you tried a slow-feed bowl? I have two rescue dogs, littermates, abandoned at very young age and lucky to be alive. However when they were in the rescue centre they had to fight to eat and drink against other, bigger dogs so continued this behaviour after I took them in. Slow-feed bowls got them to slow down and eat/drink at a better pace and help reduce the amount of air the dog intakes when swallowing, meaning less burping. Something like this is what I mean: https://www.amazon.co.uk/JasGood-Eco-friendly-Durable-Non-Toxic-Preventing/dp/B01F8L63ZG/ref=pd_lpo_vtph_199_lp_t_2?_encoding=UTF8&psc=1&refRID=0A7T83D1NQB5VVKQS511

To be clear, the orbital periods of the planets are not neat ratios of one another, with regular perfect alignments. I assume it was portrayed that way just to show one revolution of each planet and/or make the graphic loop better. (In the graphic Neptune completes one revolution in the time it takes Earth to make six; in reality a Neptunian year lasts about 165 Earth years.)

For a more accurate representation of the orbits in our system check out this visualizer: http://www.solarsystemscope.com/

Zoom out, view it from the "top," speed it up, and set the orbits to realistic. Edit: Actually, the Orrery model may be better for getting the initial impression of orbital periods; just know that it's not at all accurate regarding size and shape of orbits.

You can actually purchase a 'real' one if you're so inclined. By real of course it's really "as close as you can get in the 3 dimensional world". But still a pretty cool conversation piece.

He coauthored an entire book about the science behind the the plot and visual effects of Interstellar. Absolutely fascinating, especially after a few hits of the old space dust.

Edit: here’s a link to the book on Amazon - The Science of Interstellar by Kip Thorne and Christopher Nolan Enjoy!

it's fairly easy.

Go here on the phone or tablet and download.

When you try to install (by tapping on the downloaded file) it should prompt you to allow install by third party sources.

Once you have F-Droid installed you just open it and search for DNS66 and then install. Run the program once to set it up.

Also check out ShatteredPixel Dungeon. It's one of the better time wasting games out there.

Most likely CSS Grids.

http://materializecss.com/grid.html

EDIT: Above is the correct link. Link below references the css grid property, as opposed to the above which references what I was referring to.

https://css-tricks.com/snippets/css/complete-guide-grid/

Good article, even if you don't know any CSS. You can see from the pictures how you can easily drop things onto a page while keeping other content stable.

Edit: Looking at the site, it's not identical to grid layout but the idea is the same - preset containers that you put next to each other to fit the fixed page width of 970px.

Editedit: Actually it's all fixed width stuff, boo!

What he was talking about is a well-known bypass where you just move the bar because the back of the lock isn't shielded, so you can poke stuff back there.

What you're talking about is over-riding the pins which is a well known attack.

Both of them can be found on the Covert Companion, sold by LockPickingLawyer himself on his website covert industries.

The override works really well on Masterlock #3's.

And, he's covered these clear locks before (dunno which video), but his opinion is that they're fun for like first 3 minutes of "This is what lockpicking is doing", and after that they're useless because you wan't to train to do things by feel, not by sight.

Instead, get one of the super-cheap Master Lock 411's. It's got a 6-tumbler core that's much more difficult to pick than a 4-tumbler #3, and is actually good training.

I'll say the same thing now that I did the last time I saw this posted here:

The orbital periods of the planets are not neat ratios of one another as they appear in the left side of this gif. The orbits do not increase in size with that regularity, the planets do not all move at the same speed along those orbits, and they do not all perfectly align every time Neptune completes a revolution.

For example: in the graphic Neptune completes one revolution in the time it takes Earth to complete six; in reality a Neptunian year lasts about 165 Earth years.

I assume this graphic portrays the solar system the way it does in order to cram a single revolution of each planet into a short gif and/or make the graphic loop better. I understand that the orbital periods are beside the point of the gif and that it still makes its main point about the sensibility of heliocentrism over geocentrism, but every time it's posted I see people assume it is completely accurate. It really needs a footnote explaining that essentially nothing in the graphic is to scale.

For a more accurate representation of the orbits in our system check out this visualizer: http://www.solarsystemscope.com/ Zoom out, view it from the "top," and speed up the simulation. That will give you an idea of the relative time involved, and after that you can set the orbits to "Realistic" rather than "Orrery" to get a better idea the sizes and shapes of the orbits.

Yes, actually! That's basically what this is. One of my friends had it in their bathroom when I was yonger, & I thought it was the coolest shit.

I used to be into falconry, and this looks like a more secure form/variant of the falconer's knot. The advantage to the latter is that it can be tied one handed.

I need to learn this knot. Very cool.

It doesn't sound too bad. They're not putting something red hot in there like the graphic implies.

>"A smaller tube goes inside the bronchoscope and warms each small airway in that part of your lung. The heat is very mild, cooler than a cup of coffee. You won't feel it or the tube touching your lungs." - WebMD

Definitely. For further reading, I recommend Wiesel's Spaceflight Dynamics.

It is much easier for a satellite to maintain its orientation if it is spinning. Otherwise, it starts to drift and point in different directions. Satellites must then be designed to spin on one of the two stable axes, because if it ends up on the intermediate axis it will wobble (and you lose your TV, cell phone connection, etc.).

What this usually means is distributing the mass of the internal components a certain way, or even adding ballast weights to set the moments of inertia as desired.

A pack of playing cards may be a simple rectangular prism, but even a complicated object like a satellite exhibits the same dynamic properties... it's just a lot tougher to figure out what the axes are.

Beyond stabilizing satellites, any maneuvering in space needs to take these concepts into account. A maneuver on the intermediate axis will be unstable. Spacecraft need to either compensate, or perform maneuvers on stable axes as much as possible.

P.S. I think they have to be designed to spin on one axis actually, but I can't remember if it's the minor or major axis. As energy slowly decays, the spin will gradually transition to one of the axes... but college was a long time ago.

Have an up to date fire extinguisher in your kitchen.

Also, have fire extinguishers in your hall closet, bedroom, car, girlfriend’s car, etc.

Give them to family as stocking stuffers

They are small and cheap and can stop a shitty situation from turning catastrophic.

Where do you live? I’ve always seen them in workplace medicine cabinets...

Band-Aid Brand Flexible Fabric Adhesive Bandages for Wound Care and First Aid, Finger and Knuckle, 20 ct (Pack Of 2) https://www.amazon.com/dp/B00CCPEEKI/ref=cm_sw_r_cp_api_i_S..nDb6WXF761

There are several good free cellphone apps for knotmaking that don't require internet connection. I have both Useful Knots and Best Knots (which has fewer, but is animated) installed on my Android. I use them surprisingly frequently, as my memory for knots sucks, so I often want reconfirmation.

Check this out first: https://www.desmos.com/calculator/otpsrtlnww . It's a 3D donut that's graphed in 2D. Slide n to turn it 90 degrees back and forth. Slide m to move it up/down in 3D. While exploring it, try to imagine how it looks in 3D, and where the 2D plane is cutting it. We can't see the whole donut in 3D, but we can still see how the rest of it fits together, by sliding and rotating around. This is using 2D to explore 3D shapes. Now take this concept, and apply it to using 3D to explore 4D shapes. We're still using a thin, sheet-like world to view a much bigger object than we can see. And, moving the 4D shape around makes a whole 3D slice morph and change.

Underhandedness is central to war (Read Sun Tzu's The Art of War, where the term used is deception). Underhandedness is used by all parties, even those with just motives (Yes, the Allies used it, too).

Attacking neutral countries can objectively leave you in a strong tactical position, even if it makes you a monster. Winning a war isn't about elegance or chivalry. It's about forcing the ebemy to surrender or be destroyed. It turns everyone into monsters.

It is important to study war, objectively, so that your children don't have to.

>CURVES: Pull. Bend at the wrist. Follow the curve of your hand as it bends inward. This will feel very natural. Always pull those curves toward your body.

>STRAIGHTS: Push. Lock your wrist and move your whole arm away from you to draw a straight line. Go slow. Pick up and start again as needed for longer lines.

https://dribbble.com/shots/2134639-Quick-Tip-to-Draw-Straight-Lines-Avoid-Shaky-Hand-Lettering

Apiarists regularly give bees sugar-water if there is not enough plant life around or it's too late in the season to artificially prop up bees. It's a fairly regular occurrence. Sysk did a pretty good podcast about bees and beekeeping if you're interested

There are risk factors that make it more likely to happen, so avoid them. They're not healthy habits anyway. https://www.mayoclinic.org/diseases-conditions/brain-aneurysm/basics/risk-factors/con-20028457

• Older age
• Smoking
• High blood pressure (hypertension)
• Hardening of the arteries (arteriosclerosis)
• Drug abuse, particularly the use of cocaine
• Head injury
• Heavy alcohol consumption
• Certain blood infections
• Lower estrogen levels after menopause

Also check the link for the symptoms of an unruptured aneurysm, leaking aneurysm and ruptured aneurysm. They are pretty severe symptoms that would likely make you think you should go to the ER anyway, which is where you should go if you suspect an aneurysm.

What exactly makes you think that? The fastest ~~point~~ path between 2 points is a brachistochrone curve. It changes when the points change. So of course the two examples won't be identical.

I'm really not sure why so many people are getting confused over this. You can play with it here: https://www.geogebra.org/m/bHQNJvZC

Notice the steeper the slope between a and b, the closer it resembles the vsauce video. The more gentle, the closer it resembles the simulation.

> There is a debate among scientists as to is viruses are actually alive

An interesting book that spends quite a few pages discussing this is <em>Life as We Do Not Know it: The NASA Search for (and Synthesis of) Alien Life</em> by Peter Ward.

Scoring a circle around a cylinder without a tool is almost impossible to do cleanly. You'd use something like this for something up to an inch or two in diameter (like a glass rod for glassworking). You'd need something similar for a larger diameter object like a bottle. And you'll always need to sand it if you don't want a razor edge.

They probably mean a dental implant to replace a tooth. The implant is made out of titanium (which goes into the jaw bone) and then they put a crown on top of it.

https://www.mayoclinic.org/tests-procedures/dental-implant-surgery/about/pac-20384622

CSS grid layout is still in working draft &amp; has almost no browser support at the moment, so a major site like New York Times wouldn't be using it.

I thought it might be flexbox, but I'm guessing they need a lot of legacy support.

You can get ice ball molds for a couple bucks on Amazon.

https://www.amazon.com/Chillz-Ice-Ball-Maker-Mold/dp/B00KI7QZ5Y/ref=sr_1_4?ie=UTF8&amp;qid=1517084234&amp;sr=8-4&amp;keywords=ball+ice+mold

I always recommend silicone molds, it makes getting the ice out much easier.

https://www.amazon.com/General-Pencil-Company-Masters-Preserver/dp/B001TNR7VM

Clean with this and leave in to keep the shape and stop them from drying out, and use synthetics for basecoating/drybrushing. A single 15-20 dollar sable brush will go extremely far for miniatures painting if you take care of it and only use it for actual detail painting. It really does make a big difference even for an amateur painter.

Amazon? They have everything.

Edit- Potassium Iodide Reagent ACS/USP Granular Crystalline 99.9% Pure 0.5 kg 500 g https://www.amazon.com/dp/B01I61J3HU/ref=cm_sw_r_cp_api_SbRTBbP2D0TJQ

Hydrogen Peroxide Solution 30%, ACS Reagent Grade 500 mL [ 1 Ea.] https://www.amazon.com/dp/B00IOYVNAU/ref=cm_sw_r_cp_api_OdRTBbGWZMEZY

Just need someone smarter to tell you if this actually the right stuff.

> I didn't know there were theories about the relation of Reimann Hypothesis and the physical world.

The most famous example was the teatime discussion in April 1972 between Freeman Dyson and Hugh Montgomery in Princeton. Dyson was a mathematical physicist and at the time was studying the energy levels of random matrices. Montgomery was studying at the time was studying the statistical distribution of Riemann Zeta functions. At the time, both didn't know each other and came up with the same equation for statistical distributions in two completely different applications where one was pure number theory and the other one in nuclear physics.

From there, famous mathematicians like Fields Medalist Alain Connes wrote papers connecting the Riemann Hypothesis and quantum mechanics, and the idea has become more mainstream.

I learned about the relationship through a overseas documentary going over the history of the Reimann Hypothesis and that it is one of the most difficult Clay Millennium prizes out there.

Not sure if serious...

But seriously, Here is a scientific paper addressing your question.

Yes it is harder to breath, and one study suggested that some eggs may be eaten to ensure proper oxygenation for the rest.

I bought this soap. It lasts for months. It's fantastic.

Amazon Prime Link: $5 for the bar of soap:

https://www.amazon.com/gp/product/B00537QFK4/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&amp;psc=1

It even has the indentation from the Mallet hit

Did a quick Google and found this.

Might start using it myself actually. I normally like to give myself a window of time to do a task and this is a pretty solid way of making a safe estimate.

Didn't you grab this from Scott Manley's Mass Effect video?

He says in the description it's from Space Engine, not NASA. Check it out here. It's a free physics engine made one dude. Absolutely stunning! http://spaceengine.org/

Feel free to play with this: https://www.geogebra.org/m/bHQNJvZC

It will draw the brachistochrone curve between two given points. If you want to mimic the video, put point b somewhere near the bottom of the cycloid. That's exactly how they made it, actually. If you want to recreate the simulation, put point b somewhere on the far side.

If you camp a lot but still want to keep it quick and easy (you’ve got kids) I recommend these:

https://www.amazon.com/dp/B084KK5P7G/

They’re like 10 cents each, they’re small flat squares so easy to pack, and work great. Easier than prettt something with wax or saving up lint and toilet paper tubes or something IMO once you’re an adult with a job (though those are still great skills you teach the kids).

This is all I could find on Amazon. Do you think it will react similarly?

That is always been Melbourne

Hence the song Four Seasons In One Day

Sometimes, against a uniform, bright background such as a clear sky or a blank computer screen, you might see things floating across your field of vision. These "floaters" are not any kind of external objects, nor are they alive. Rather, floaters are tiny objects that exist inside the eyeball, and cast shadows on the retina - the light-sensitive tissue at the back of your eye.

If you'd like to learn more about floaters, watch the TED-Ed Lesson What are those floaty things in your eye? - Michael Mauser.

= Animation by Reflective Films.

The best visualization and explanation I've seen is in this series on Netflix called "The Physics of Light": https://www.netflix.com/search/physics%20of%20light?jbv=80067800&amp;jbp=0&amp;jbr=0

They're all good episodes, I'm not sure the native language, but it's dubbed in English. There is one episode in particular with a great illustration of time dilation, easily the best one I've seen. I've been interested in physics my entire life, and have studied it as a hobby but this one episode gave me my "ooohh that's what they mean!" moment.

Edit: The first episode, start watching about 36 minutes in, and at around 37-38 minutes it'll get into it. That's the best explanation of time dilation I've seen. Hope it helps.

In the 1980s and ’90s, the Sistine Chapel underwent a long and elaborate restoration scheme sponsored by a Japanese television corporation and carried out by top Italian and international experts. The cleaning removed centuries of grime, dust, and candle smoke from the frescoes and revealed unexpectedly brilliant colours that partially contradict the celebrated sculptural qualities of Michelangelo’s masterpiece. A fierce controversy—involving scores of restorers, art historians, and experts in related fields—surrounded the project from its very beginning. The debate centred on one major issue: had Michelangelo, in the manner of fresco painters of the day, modified his finished fresco with secco (dry) paint after the plaster had dried? (Fresco painters customarily did this as a means of correcting mistakes, refining their works, and applying pigments that could not tolerate contact with water.) And if so, had the restorers’ removal of every layer down to the frescoed plaster falsified the artist’s intentions? In this case, the shadowing, corrections, and glues removed by restorers appear to have been the result of previous restoration campaigns, although the issue is still debated.

Hello, I'm a bot! The movie you linked is called Dark Star: HR Gigers Welt, here are some Trailers

Here is an adjustable graph that lets you play with the number of terms in the series!

The Fourier series is shown in black, and in orange you will see each of the individual sine waves that are being added at each step of the series.

EDIT: I added a Fourier series showing how to create a sawtooth wave as well.

I paid $12 for a two pack at Costco.

The hazelnuts on amazon are $17 alone.

As does Relay!

Play store link : Relay for reddit
Promo Video : Relay

That's silly. If this was an industrial chicken farm video, fine, but it's a beat harvest.

> farming isn't what it used to be

Why are you nostalgic for a back breaking labor you've likely (luckily) never experienced?

> inexpensive food gives us comfortable lives, making us rich

No, inexpensive food gives us food, making us not starve to death. At the time I'm writing this there are roughly 7,575,083,547 people on the planet. That is far too many people to feed off delicate heirloom veggies grown by mammy and pappy with their hand tools.

Even with the amazing advancements in productivity and yields humanity has come up with there are still so so many people starving to death right now

> turned nature into a source of raw materials, rather than an object of appreciation

Not mutually exclusive. Even if they were, you think animals like birds don't consume raw materials from the earth?

Normally you wouldn't want ferrofluid around kids. It shouldn't be drank for obvious reasons, and it's extremely messy if it gets on clothes, furniture, etc.

You can buy fluid on Amazon https://www.amazon.com/Ferrofluid-2oz-Bottle-Science-Projects/dp/B00126P1NW. Get an enclosed glass decanter to put it in and some neodymium magnets.

I've been using this one off amazon. It's a bit pricey, but will honestly change how you wake up each morning. Each morning It goes from a very muted red (like early sunrise) all the way up to a full bright white light like a solar lamp. And you can adjust the brightness/lightness of it like a lamp for normal use. I love using it at the lowest light level before bed, and any time you turn it on or off it fades the brightness/darkness so it's not a shock

Hahaha! Have you been living under a rock? The technology which you think can't ever exist already exists!

http://mashable.com/2014/04/28/3d-printing-houses-china/

That's just one example. There's all sorts of new concrete 3d printers out now and coming to market soon. Many of them are incorporated into larger robots that can print entire buildings and other structures (e.g. well heads, dams, etc).

Two spaces at the end of a line is used for getting a line break without creating a new paragraph.

The > character is used to create a quotation. Four spaces at the beginning of a line is what you use for code.

Everyone should use Reddit Enhancement Suite, which shows you, as you type, what the rendered comment will look like. (On mobile phones, all hope is lost.)

It looks like Johnson's money came from his wife's investments into early radio and television. She used her inheritance to buy several radio and TV stations, which ended up bankrolling his campaigns.

On the other hand, the Clinton number seems to actually be his post-presidential wealth from his book sales and speaking engagements. The Clintons listed their net worth as $700,000 in 1992.

Don't be an alcoholic. The condition that can cause this is called Avascular Necrosis, "Avascular necrosis is associated with long-term steroid use and drinking too much alcohol. It's most common in people between the ages of 30 and 60 and often affects the hip." I know because I was diagnosed last week and am scheduled for surgery next month. I did have an accident with massive trauma, but also loved to drink. Make sure young you takes care of old you.

Here's an interactive version I put together in Desmos a few years ago: https://www.desmos.com/calculator/qq2hz6qw7d

It's great that we now have computer programs to show these concepts way more easily than just looking at a sheet of paper.

View this Gif as a Html5 Video!

GIF size: ~344 kiB || GFY size: ~107 kiB || Compression Ratio: ~3

^(Gif2GfyBot here, I convert GIFs subreddit to bandwidth-friendly and quick loading HTML5 videos!)

> Should I go get a mouth guard ASAP?

If you grind your teeth: yes. If you don't see the effects of the grinding on your teeth yet, you're lucky. I have this thing called "Bionator" over here, but there's just a German wiki on it, there might be other versions of it, but it looks like this: https://www.qwant.com/?q=bionator&amp;t=images . It cost a bunch, but it helps a lot to prevent that loop of tensing up because you grind and grinding more because you tense up. Also, I have less issues with breathing at night. To save your teeth a casual mouthgard might be sufficient.

CamScanner works great for things like this.(I also have the G4, camera is great), and the premium version has OCR built in. If you sign up with a .edu email you get premium for life.

Also Calibre is great for converting to ebook format and it also has OCR.

no /r/HailCorporate I'm just a college student and use these a lot.

I don't know much about woodworking either, but I believe you could just chisel them out like this:

https://www.shutterstock.com/video/clip-2423897-stock-footage-carpenter-using-a-chisel-to-cut-a-joint-in-a-wood-board.html

Gave it a try this morning because I've never had it before. Result... nice, but not as amazing as I was expecting:

https://photos.google.com/share/AF1QipO9jiPozfcc8bG8KWubAYV4LZ-gpOu2F4x0mfx8XfO099Z4GEvnAebYx31AyzliLA/photo/AF1QipP_D16alRNSBdeIRriGSHKGPjP5jaq0-p8ILeeL?key=THNlaTRITGNyS1lSbmdLWkFHOHYxeUtmMjFuV1h3

Along with the suggestions below to shop around the price, there is great company on Amazon that will send you a mold kit and then after you send it back they send you a mouthguard and your mold back for future use.

https://www.amazon.com/Dental-Lab-Mouth-Guard-Lower/dp/B0769GHPRX/

Easy as fuck with

Play store link : Relay for reddit
Promo Video : Relay

They use several systems. makes it easier and faaster to get an accurate location.

https://play.google.com/store/apps/details?id=com.android.gpstest

You can download this app (in android) and it will thell you the satellites you phone can hear and the system they belong to (in the form of a flag)

&#x200B;

Mine (samsung A8) is able to listen to GPS and GLONASS

Yeah, it's a type of LCD panel. Though I'm not certain that matters. I've been reading through the comment thread where that experiment originated and it's been suggested that the noise is produced by capacitors on the board that drives the display, rather than the display itself. This makes sense to me, as the noise gets much louder when listening from the back side.

So it's likely like the random hums and buzzes (not caused by fans or drives) PCs sometimes make, only this time it's easy to control by drawing stuff on the screen.

I'm the author. I used my own drawing library for it.

But I'd recommend others to use manim (3blue1brown's library) or Processing instead.

Geogebra is good for sketching, but the GIF exporting is kinda wacky.

probably something like this (python):

# divmod(a, b) returns two numbers; the first one is floor(a / b), the second is a % b # so divmod(18, 10) returns 1 for the first number, and 8 for the second

# literally just some random number money = 827

hundreds, left = divmod(money, 100) # hundreds = 8, left = 27 fifties, left = divmod(left, 50) # fifties = 0, left = 27 twenties, left = divmod(left, 20) # twenties = 1, left = 7 tens, left = divmod(left, 10) # tens = 0, left = 7 fives, ones = divmod(left, 5) # fives = 1, ones = 2

this doesn't handle being low on certain bills, but eh

edit: this handles bill counts

There was a good BBC documentary on the lives of those in Ghana who recycle some of this stuff. Bit of an eye opener.

By that, I meant the throat or 'bottleneck' of the 1-sheet is circular shaped, and morphs into an ellipse, identical to the sphere from the 2-sheet.

Basically, the conic sections (circle, ellipse, parabola, hyperbola) can all come from slices of a single surface: the two infinite cones that touch at the tip. Changing the angle and depth of the slice makes different curves.

A 4D version works the same way, but now we get 2D curved planes, instead of curved lines. When looking at the slices of a 4D conic surface, keep in mind that a sphere, ellipsoid, paraboloid, and hyperboloid (3D versions of circle, ellipse, parabola, hyperbola) can all come from intersections of a single, 4D infinite cone-like surface, that touches at the tip at origin. Those 3D objects/surfaces are made depending on how the 4D conic is sliced.

You can do it mathematically, by setting a dimension to zero in the equation. So, take a cylinder for example:

|√(x²+y²) - z| + |√(x²+y²) + z| = a

This equation has three dimensions, describing a circle xy getting multiplied with a line segment z. If setting y=0, we get

|√(x²) - z| + |√(x²) + z| = a

which is a square slice, having only two dimensions.

If setting z=0, we get

|√(x²+y²) | + |√(x²+y²)| = a

which is a circle slice. And, if we rotate the cylinder in 3D, it morphs back and forth from a circle to a square. Here's a cylinder graphed in 2D slices. Adjusting M slides, and N rotates in 3D.

This is a good book about the basic history of math. I had to read it for an undergraduate elective but ended up liking it very much because it gave me a new appreciation for all the amazing discoveries that you're asking about. The book is short and concise and reads like a popular science book rather than a textbook.

Some of the ancient mathematicians had genius brains that just work differently than common brains. And others spent a lot a lot a lot of time carefully drawing and measuring and calculating. Same as doing a long division problem these days on paper instead of using a calculator--more time-consuming but still doable.

Slightly unrelated so I'm making a second comment.

My daughter was over focused on the bad things that happened throughout the day so I had her start counting the good things/thoughts that happened using a tally counter

I put it on a lanyard and had her click it every time something good happened or she had a good thought. She could mention bad moments, but she wasn't allowed to say she had a bad day unless her tally was below a certain count. After a couple weeks her thinking started to adjust and she didn't need the counter anymore.

The only one I could find was $89k on amazon

Edit: formatting

i'm no expert but according to lockpickinglawyer on youtube, the abus plus core is only pickable by a "handful" of experts in the world. this is a guy who has picked countless locks that are very difficult and says he himself can't pick it right now. he does pick it in a later video but says he can only pick it quickly because he's picked that same lock multiple times. so a lock like that would not be pickable for a burglar because even if he was an expert, he'd have to stand there for a long time to pick it. also very few can pick it.

https://www.youtube.com/watch?v=L6iMmCSayBQ&amp;t=103s

i found a different lock with the same abus core on amazon for about 35 bucks. i'm sure they make a deadbolt somewhere.

https://www.amazon.com/ABUS-20-70-KD-Stainless/dp/B009S5Y6ZS

i personally never went beyond picking schlage deadbolts. when i picked a schlage, all i did was raked it. it's a similar action to a lock pick gun.

I had it on Netflix dvd. Gotta check if it’s anywhere else.

Edit: here is Amazon rental

Amazon?

You can get a little cotton candy maker and several flavors of flossing sugar on Amazon for like 30 bucks. I recently bought one and it's awesome!

https://www.amazon.com/dp/B00EB8KRDM/ref=cm_sw_r_cp_apa_i_Kt2SDb0SNSVDY

Edit: oh and you can make any hard candy into cotton candy. Yes jolly rancher cotton candy is awesome.

Well, imported high quality food costs a lot.

When you buy italian food you can check if is true Italian food with the barcode with this app: https://play.google.com/store/apps/details?id=com.authentico

This are the prefixs of Italy 800 – 839 GS1

There's an app my kids use (and love) called Dragon Box Algebra that does this both with pictures as well as with numbers and variables. Not exactly this, but alike. Here it is in the Google Play Store.

Home serology kit.

I can't grantee it is correct.. but. I just did 1 google search, if you're interested in finding out, I bet you can find better kits/ways

https://www.amazon.com/Blood-Typing-Activity-Home-School/dp/B072YYNJCY

Wow, I'm impressed with /r/tipofmytongue. Someone identified it within the hour.

Edit: I guess I misremembered that it contains 3D objects as well, it's just 2D objects passing through a line. But it's fun.

Depends where you are: https://weather.com/science/space/news/great-american-solar-eclipse-speed-of-moons-shadow

Different eclipse but same principals.

Hmmmm... well there's this great new book and I hear the author is a swell guy, and it was written for folks with that exact background and interest.

https://www.amazon.com/Essential-Math-Data-Science-Fundamental/dp/1098102932/

*kidding aside, I'm the author. Reddit folks, I promise I did not plant u/iamnerdyquiteoften as a seminar caller.

They gave us these to carry around if we wanted them:

https://www.amazon.com/Shield-Keychain-Keying-Shields-Training/dp/B07FDYGVNV/ref=mp_s_a_1_3?keywords=cpr+mouth+guard&amp;qid=1658361605&amp;sr=8-3

If you want an idea of how Lake Mead and Glen Canyon looked before they were dammed up, the book The Emerald Mile is fascinating.

More stupid shit no one needs?

RII 6pcs 2.5" Nautical Decorative Rope Ball, Cotton Rope, Nautical Bowl Filler, Rope décor, Vase & Tray Bowl Filler, Home Tabletop Décor, Wedding and Party Display Props, Housewarming Gift https://www.amazon.com/dp/B075FTLMB9/ref=cm_sw_r_apan_i_1CJB8R876CBVGEYN4VQX

There's a really interesting book about fly tying called The Feather Thief by Kirk Wallace and it's one of my favorite books

https://www.amazon.com/Jinhan-Ramyun-Soup-Powder-285g/dp/B01MQQEMQJ/ref=sr_1_2?crid=31PE4IKDKJHV6&amp;keywords=ramen+flavoring+powder&amp;qid=1644541920&amp;sprefix=ramen+flavoring%2Caps%2C137&amp;sr=8-2

It's a trick one, you can buy them on Amazon cheap

Enjoyer New Nut Off Bolt Screw Close up Magic Tricks Super Ultimate Rotating Magic Gimmicks https://www.amazon.com/dp/B07VP413C6/ref=cm_sw_r_apan_glt_i_N185BZMQGJCYM3AQCY5H?_encoding=UTF8&amp;psc=1

Without knowing much about sorting algorithms, I inadvertently implemented bubble sort when I got to the sorting level in Human Resource Machine. Great game.

I'm reminded of the story of Richard Feynman using the slack in these types of locks mixed with with a bit of human psychology to notoriously break into locked top secret file storage in Los Alamos during the Manhattan project. A crime today that would surely have him sent to prison for the rest of his life, but was then a gag he pulled on some of the smartest mathematical minds in the United States, much to their bewilderment.

http://www.openculture.com/2013/04/learn_how_richard_feynman_cracked_the_safes_with_atomic_secrets_at_los_alamos.html

Fair enough, taste is subjective after all. It's not very commonly supported but I actually really like the font ubuntu uses in such cases, it's quite unique for a interface font but still easily readable. Or Montserrat for fancy titles.

https://fonts.google.com/specimen/Ubuntu?query=Ubuntu

https://www.desmos.com/calculator/goisiajxwe

ϕ here is the relative phase between the two coordinates, which controls the same thing as the "starting position" in the original drawing. Something I think you can visualize from this animation is that it's the same as if the curve is a wavy line on the side of a rotating, see-though cylinder.

This gives a geometric relationship between the diagrams you wanted to be the same in the post: start with a curve below the diagonal, rotate it (in 3-D, as if on a cylinder) until one of the troughs (low points) is centered, and then rotate it (as a flat picture) so that "up" goes to "left".

Because they x and y start 90 degrees off from each other.

(sin(2θ), cos(θ)) ≠ (sin(θ), cos(2θ))

but

(sin(2θ), cos(θ))
is
(cos(θ), sin(2θ))

rotated by 90 degrees

https://www.desmos.com/calculator/cz00q3yw8o

Have you seen this similar one, kindly shared by another commenter, which also includes the cotangent, secant and cosecant?

https://www.geogebra.org/m/Gg7ZteS3

I'm familiar with those functions but this visualisation was as new to me as the tangent was.

Ah, sorry. This isn't actually the my favourite visualization. Here's the one I usually use.

https://www.geogebra.org/m/Gg7ZteS3

So you create a segment at the angle. Where it meets the unit circle, you draw a tangent line to the circle. You also extend a line down so that it is perpendicular to the x-axis.

That's not a referral link it's a normal link with the product id Try it yourself, just search for "DCT Equal Space Divider Tool" and click the same product and check the URL. https://www.amazon.com/dp/B082DN15ZN also works.

https://medium.com/feedium/how-to-tell-if-a-link-is-an-amazon-affiliate-link-9869aab25ecf

Anyone interested in deep understanding of physics taken into animation form, check out Joseph Gilland “Elemental Magic”, hes an animator that specializes on element representation and has developed a few techniques for stuff like the waves and rain in movies like Lilo and Stitch for example

https://www.amazon.com/Elemental-Magic-Special-Effects-Animation/dp/0240811631

It's indicative of a thunderstorm but they've done studies and green sky is not more likely to produce tornadoes than normal thunderstorm conditions. So yes green sky is indicative of severe weather but not necessarily tornadoes.

https://www.accuweather.com/en/weather-news/fact-or-fiction-a-green-sky-means-a-tornado-is-coming/332831

Its most common on lake Michigan due to it's shape and position, kills about a dozen a year. Sometimes you get a real ironic one where some guy with ocean experience thinks "its just a lake".

> I also remember reading somewhere that adding another period after .com (www.example.com./whatever) will bypass paywalls because it registers the user as a fully qualified user

This is true, but won't always work. It used to work with nytimes.com, then didn't, worked again, and now it doesn't anymore.

I use a custom javascript extension so I can write my own code for whichever website I want to change and for some of them I use the following snippet:

if(window.location.host !== "outline.com"){ window.location.replace(http://outline.com/${window.location.host}.${window.location.pathname}); }

This works for many sites, like forbes, independent.co.uk, etc.

For sites where it doesn't work, like wapo and the nytimes, I write custom code. Basically the same as this educational gif does, change the css properties of the page so it works again.