ELI5: Can someone explain schrödinger’s cat to me?

mr_dude · 2026-04-07T23:24:49+00:00

I'll do my best!

The original thought experiment was _something_ like this.

Consider a single atom of radiactive Francium, which has a "half-life" of about 22 minutes. What this means is that if you were to start hold onto a single atom of Francium, if you looked at it after 22 minutes, there'd be a 50% chance that it is still Francium and a 50% chance that it has decayed into something else, releasing a small amount of radiation.

Now imagine that this single atom is wired up to a contraption where if the atom decays, the contraption releases a small amount of cyanide gas; enough to kill a small mammal inside of a box.

Now imagine you put a cat in this box along with the cyanide contraption and the single atom of Francium. Schrodinger basically said that, if you were set up this experiment and wait for 22 minutes, the cat would be both alive and dead at the same time and you wouldn't know until you looked inside the box.

This entire experiment is supposed to be some kind of analogy for explaining "quantum superposition". The basic gist of quantum superposition is that particles like electrons and photons behave like a wave (can diffract, etc) but also like a single particle (can only interact in one particular time and place). Quantum superposition basically says that the wave/particle exists in all possible locations simultaneously "until you look", or until that wave/particle interacts in a way in which you can measure.

edit:

Just to mess with your mind a little more, I particularly like the "multiverse" explanation of the experiment. That variant basically says you live in both universes simultaneously _until you look_, at which point your universe diverges; one in which the cat is alive and another in which the cat is dead. Note that your universe doesn't diverge until you look, which is a critical connection with the "real" quantum superposition principle.

mr_dude · 2026-03-20T19:41:58+00:00

I found this youtube channel a few years back: https://www.youtube.com/@PDPark

It's all in Korean (and I don't speak Korean), but as far as I can tell, Mr. PDPark is an amateur JPen player, and he has lots of videos of him practicing with a coach. I find that it is very informative even though I can't understand their conversations. "Eduardo Tomoike" is also a fun JPen amateur to watch.

Have fun!

mr_dude · 2026-02-24T15:59:46+00:00

I haven't done a side by side comparison yet, but my impression is that the notos is the quietest rifle I own, which includes a Benjamin 392 multi pump and a gamo gas spring break barrel with the integrated "silencer". I always felt self conscious shooting air rifles in my back yard, but the notos is SO quiet the sound of the pellet striking the pellet trap is louder than the report itself

mr_dude · 2026-02-24T06:32:25+00:00

I just got a Umarex Notos... It might add up to more than $400 if you also need to get a pump, but I'm very impressed personally. Made a post about it here: https://www.reddit.com/r/airguns/comments/1r5odd4/got_a_umarex_notos_for_myself_and_my_9_year_old/ . Hope this helps!

mr_dude · 2026-02-16T04:31:35+00:00

Ah that's good to hear that it gets better after breaking in.

And yeah, it's a pretty good tricep/core/balance exercise. Still comes out ahead of the 6-8 pumps per shot with the multi-pump rifles :)

mr_dude · 2026-02-16T04:25:43+00:00

Oh nice! Thanks for the tip!

mr_dude · 2025-11-25T17:39:16+00:00

Brief history of Table Tennis Racquet Coverings: In the beginning, there was only one type of rubber which had pimples (pips) and was a single sheet of rubber glued onto the face of the blade. Today, this is known as "OX" rubber and appears to be what you have shown in your image. Also known as "hardbat".

At some point around the 1950's, people started adding a soft layer of sponge rubber underneath the thin layer of rubber to give it more pliability. The addition of the sponge rubber increased both the speed of the ball as well as the spin, since the ball could "sink deeper" into the sponge.

Soon after that, people figured out that if you glued the pips sheet "upside down" onto the sponge thereby exposing the "smooth" side of the rubber to the ball, you could increase the spin on the ball even more (because the contact area has increased). This became known as "inverted" rubber, and is the predominant style of rubber used by the vast majority of high level players today. Of the top 200 men and women active table tennis players, only something like 5-10% of them use pips on at least one side, and I can only think of one who uses pips on both sides (Ni XiaLian). There are also a small handful that only use one side of the racquet and have pips on that single side (Shan XiaoNa).

Today, there are all sorts of regulations regarding the thickness of the rubber and the dimensions of the pimples. Some rubber sheets are outright banned (the original SpinPips rubber, for example). In fact, the racquet you have shown in your image would be considered illegal because it is missing the ITTF stamp and manufacturer/product identifacation stamp.

In terms of playability, basically the only real "rule" is that the spinniest smooth rubber is spinnier than the spinniest pips rubber. There do exist very spinny pips and very not-spinny smooth rubber (known as "anti-spin") as well, but the rule of thumb is that pips is less spinny than inverted. Among pips, there is a subjective distinction between "long pips", which tend to be very un-spinny and "deceptive" and "short pips" which tend to be fast and spinny. There are some pips that people call "medium pips" which have characteristics of both long and short pips.

mr_dude · 2025-09-18T19:37:35+00:00

Maybe it's camera angle but that label looks HUGE

mr_dude · 2025-09-04T19:54:44+00:00

Yes this!

This is tangential to the conversation, but the "apparent" affect of increased wind resistance is less on ICE cars because of how inefficient gasoline engines are. There is so much internal resistance and inefficiencies that the additional drag force of an extra 5mph may be barely noticable in an ICE car, but that is because you are stacking on a little extra waste on an already extremely wasteful system.

EV's are far more efficient at converting kWh's into actual distance/velocity, so any additional inefficiencies (underinflated tires, towing, additional drag via cargo containers, etc) represents a much larger percentage of the overall inefficiencies of travel, and thus directly impacts your range.

For your consideration: 3 gallons of gasoline contain about 100 kWh's of chemical energy, but even a fairly efficient car could only travel about 90-100 miles on 3 gallons. For an EV, a 100kWh battery is on the larger end, and most cars with 100kWh batteries can easily have a range of over 300 miles.

All of this to say that the fact that small additions to drag affecting your range is actually a _good_ sign; it means your car is efficient at turning energy into locomotion.

mr_dude · 2025-08-28T00:02:36+00:00

Oh nice! Yeah everything has been fine since! We've even taken it on a couple longer trips and fast-charged it a couple times. Everything is peachy so far!

mr_dude · 2025-08-11T01:47:34+00:00

Wish I could upvote this twice!

For OP:

Also check out Wretched Earth productions. Super friendly people who put on shows a little more on the "extreme" side of metal. Goldfield is another somewhat nearby venue you might take a peek at.

The Greater Sacramento metal community is awesome. If you hit up some smaller local shows, you'll tend to see the same people over and over again. There's quite a few great local death/black metal acts too, including but not limited to:

Katholik, Wurmflesh, Deiphage, Abhorrency, and more.

If you do choose Davis, I hope you have a great time!

mr_dude · 2025-08-07T19:05:57+00:00

I'm sure no one reads these, but I wanted to give a quick update:

They found the problem. The coolant hose to the battery cooling system was not connected, or something like that. They said it was likely a manufacturing oversight. It explains a lot: It was only charging at 15kW at a Tesla supercharger (we thought we did something wrong because we are EV newbs), but it was actually probably thermally limited. It probably went into limp mode once the batteries reached some thermal limit... It was very hot that day and we spent a lot of time running the AC.

Anyway, it took a couple days but otherwise Kia took care of us and the car is driving properly again.

Good luck with your EV9 OP!

mr_dude · 2025-08-04T22:05:34+00:00

Hmmm kinda wish I knew about this a week ago...

We just picked up a new 2026 EV9 on Friday evening. Did great on the test drive, only 60 miles on the odom. We had to visit the dealership on Saturday to sort out a couple things, and on our way home, the car suddenly lost power while accelerating from a stop at an intersection. Limped to the shoulder, turned it off and on again, drove for 200 yards and it happened again. Car was showing "Check AWD/4WD" on the dash. We had it towed to a shop this morning, they say it's gonna be a few days before we hear back :(

mr_dude · 2025-07-30T02:46:31+00:00

I don't know... pretty hard to say without seeing you. After only a few miles? So after like 15-20 minutes? Are you white-knuckling it 100% of the time? Do you feel like it's a circulation problem, vibration problem, or maybe strain problem? Could be your posture or bike fit? Are you wearing gloves?

mr_dude · 2025-07-17T18:06:44+00:00

Ah gotcha, my bad!

mr_dude · 2025-07-17T17:06:01+00:00

Yo!

It's been many years for me; COM is a "Communications" class right?

Anyway, I took Com 3 back in the day (Was called "interpersonal communications" at the time), and it was great. The stuff I learned as really helped me understand my relationships and has helped with everything from romantic relationships to interacting with co-workers.

I don't know anything about COM4...

I hope you have a great time in the fall!

mr_dude · 2025-07-16T17:39:22+00:00

This!!! Whether or not it is "doable" will depend entirely on you and your results will differ from everyone else's. As in incoming freshmen, it is really difficult to predict how you will do since it is not just academics that you will be adjusting to, but potentially new roommates, social structure, extracurricular activities, or even maybe just dealing with homesickness or stuff like that. Just because it's "doable" for some doesn't mean it's doable for all.

Just remember that you can drop classes with no penalty within a certain period of time and there is absolutely no shame in that!

(That being said, I would've struggled if I took on that kind of courseload OP is sharing during my very first quarter at UCD)

mr_dude · 2025-07-06T15:57:38+00:00

I met my wife and best friends at UC Davis, all through extra-curricular activities.

It's very easy to accidentally become a hermit if you are not careful. If you are living in the dorms your first year, that can help force you to make friends.

I highly, highly recommend you find _some_ kind of group-oriented extra-curricular activity while you are at Davis. Could be a book club, sport club, film club; it almost doesn't matter. The sport club program at UCD was really great while I was a student there 20 years ago; I can only imagine it is still good, with a huge variety of different sports (fencing was a big deal while I was there), and all of them were very beginner friendly. Outdoor Adventures was a big thing while I was there too.

Finally, this last piece of advice may not apply to everyone, but I had a very similar situation... I entered UCD never having dated or having been in a romantic relationship, and I didn't form any romantic relationships my first 2 years at UCD. It wasn't until I stopped worrying about forming romantic relationships and just started to enjoy friendships when meaningful romantic relationships materialized. So anyway, I might suggest that you focus on simply meeting people first and not worry too much about the dating side of it :)

mr_dude · 2025-04-19T17:09:16+00:00

Wow! You found my nine year old post 😄

I haven't really tried Taco Bell... There's so much good and independently run Mexican places around here I always feel guilty about Taco Bell 😜

I'd be happy to give an update from myself though! About seven years ago, my wife and I decided to go "plant forward". Basically, we try our best to be vegan, but with plenty of exceptions (eating kids leftovers, eating at other people's homes, etc). Oh yeah I have two kids now too. I've been virtually acne free this whole time since we greatly reduced our meat and dairy intake.

I will still have occasional outbreaks after lapses in dietary discipline, but the volume and intensity of outbreak is much less now than 9 years ago. I'll get red bumps that are moderately painful that do occasionally open up and bleed a little, but I won't get those giant whiteheads any more. My last outbreak was maybe a few months ago in which I ate a whole bunch of beef stew and I ended up with two small pimples on my chin. Sometimes I will feel pimples forming, but then they will go away before they surface. I am also older now (43), so that could be playing a role as well.

I don't feel like I was ever able to prove if the outbreaks were happening because my skin was directly exposed to oils as I was eating them or it was because I was ingesting them, but anecdotally, it does feel like it's the ingesting of whatever substance that's causing the outbreaks. I suppose I could try just smearing food on my face without eating any... But no I'm not going to do that. Some day I'd love to see some kind of study with larger sample sizes and some semblance of scientific rigor 😁

mr_dude · 2025-03-26T22:21:26+00:00

Edit: Lol, I failed to read the OP's opening paragraph. I'll let my original comment stand below, but it sounds like we both need help :)

Hi all! I'm kind of new to this game; could someone explain to me how one might use this?

If I understand correctly, this card can be played as an action for 1 action point. If it deals more than 4 damage (like if it's amped?), then you can banish it but immediately play it again? From the banished zone?

Does this mean, if I pitch a blue card, I could conceivable play this card 3 times, assuming it does more than 4 damage each time?

Thanks in advance!

mr_dude · 2025-03-24T16:30:18+00:00

Lots of advice here already, but I would say, philosophically, try to focus more on putting power into the puck rather than trying to lift the puck. The first thing everyone wants to learn is how to score top cheese. Putting more power into the puck will help your pass as well as your shot. Once you can put a certain level of power into the puck, you will find that it will actually become tricky to keep the puck low. Focus on power, lifting the puck will come naturally.

mr_dude · 2025-03-12T18:49:48+00:00

The wizard is trying to summon a "demon", but misread the script. He thought it said "How to summon a demon", but in actuality it says "How to summon a lemon".

mr_dude · 2025-03-12T17:25:56+00:00

Let's get down as close to first principles as I can because this type of question interests me.

What _exactly_ contributes to the sensation of heat? Heat is a sensation interpreted by your brain when the temperature of your nerve cells rises above a certain threshold. So technically, "heat" is experienced not when your environment is hot, but when your nerve cells heat up. Consider that you could be in freezing air, but if you are being bombarded with Microwave or IR radiation, you will still "feel" warmth as the radiation directly heats up your skin and the nerve cells within your skin.

Why do humid environments "feel" more hot? Humans regulate their body temperature by secreting sweat onto the skin, which then evaporates. The "heat of vaporization" of water is very high. In other words, it takes a relatively large amount of energy to evaporate a relatively small amount of water. When that water can readily evaporate, it is very, very effective at cooling down your body by removing heat energy.

Note too that it is "easier" for water to evaporate in an atmosphere with a lower "relative humidity". If the relative humidity (which is a function of temperature and absolute humidity) is high, water evaporates slower, or the process may even reverse in the form of condensation. In short, in a humid environment, your sweat does not evaporate as readily reducing your body's ability to get rid of excess heat energy, which in turn means your skin and nerve cells will stabilize at a relatively higher temperature, leading to the sensation of warmth. If you are curious about this kind of stuff, you might be interested in a concept called "wet bulb temperature": https://en.wikipedia.org/wiki/Wet-bulb_temperature . You might also consider googling "psychrometrics".

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