Why does a spray bottle work? • Hacker News Board

Re: Why does a spray bottle work?

#71

Post by [deleted] » Sat, Jun 09, 2018, 10:03 PM UTC

mbell wrote: post #42

rossdavidh wrote: post #33

Earlier quoted context omitted.

However, I think it would have been quite difficult for me to get the concept of "holes" in semiconductor current, which are positively charged pseudo-particles created by the absence of electrons, if I hadn't been able to think of them as being like bubbles in a fluid. They go the opposite way of the fluid flow, and they are somewhat particle-like. So it's not a totally broken analogy, it does help to clarify some t…

I generally found the fluid analogy did more damage than good for a lot of people in EE school. A lot of people think of electricity as electrons zipping around a circuit at the speed of light due (at least in part) to the water analogy. Having to transition from that world to thinking in charge transfer and fields while electrons move around linearly at a snails pace if at all was very difficult for many people. I'd…

[deleted]

Re: Why does a spray bottle work?

#72

Post by disqard » Sat, Jun 09, 2018, 10:05 PM UTC

fjsolwmv wrote: post #60

richardfeynman wrote: post #52

Earlier quoted context omitted.

Michael Faraday gave a great series of lectures on how candles work that also illustrates the difference between cursory knowledge and explanatory depth. Most people think they know how candles work, but when you dive into the details there are all sorts of interesting things going on. https://en.wikipedia.org/wiki/The_Chemical_History_of_a_Cand... (you can also buy the lectures in book form on Amazon.)

Engineer Guy (a fantastic YouTube channel for learning how things work) has an audiovisual curriculum for this book. http://www.engineerguy.com/faraday/

Thank you for sharing this!

Having watched the first lecture, I was thoroughly impressed by the design and presentation of this historical artifact, with (judiciously chosen) modern embellishments.

Re: Why does a spray bottle work?

#73

Post by icantdrive55 » Sat, Jun 09, 2018, 10:07 PM UTC

MichaelApproved wrote: post #41

vanilla-almond wrote: post #28

A few years ago, a British inventor appeared on a TV show called Dragon's Den (UK version of Shark Tank) and pitched his idea of an improved spray bottle called the Anyway Spray. Instead of a normal plastic tube inside a bottle with an opening at the end, he designed a tube with millions of tiny perforations along its length. This meant the spray bottle could operate at any angle (even upside down) and could empty al…

Why isn't this in everything? I'd easily pay an extra few cents to have this in spray bottles. It's such a frustrating problem.

I think most companies basically just care about the over priced chemicals they sell in the sprayer.

They want a sprayer that just empties the product, so the consumer can buy more?

I try to reuse sprayer bottles. Some bottles allow this, but it's getting harder to get the tops off. I usually refill the opened bottle with 10% bleach, and water. I use the spray bottle until it stops working. Sometimes I use ammonia instead of bleach.

Ironically, it sounds like this guy's invention might use more liquid per squeeze; hence causing the consumer to buy more pricy liquid? Maybe, I'm wrong?

Re: Why does a spray bottle work?

#74

Post by mbell » Sat, Jun 09, 2018, 10:26 PM UTC

neuralRiot wrote: post #46

mbell wrote: post #42

Earlier quoted context omitted.

I generally found the fluid analogy did more damage than good for a lot of people in EE school. A lot of people think of electricity as electrons zipping around a circuit at the speed of light due (at least in part) to the water analogy. Having to transition from that world to thinking in charge transfer and fields while electrons move around linearly at a snails pace if at all was very difficult for many people. I'd…

The way the analogy was explained to me when i was a student is that the conductor is a hose filled with water, when you open the valve the water comes out instantly at the other end because the "charge" is moving. It was never confusing to me.

I think the analogy can work, but needs to be carefully applied. This wasn't an analogy taught in my EE program, but one that is common in TV programming and provided by high school science teachers whom may not themselves understand the nuance so many came into the program with this understanding in place.

Ultimately though, this concept was the breaking point for my EE class; It's when half the class dropped out to other majors. Not that I blame the analogy entirely for this, I think in general this is the point at which a lot of people lose connection with deeper sciences. It's the point where analogies to the physical world (matter) break down because we're now fundamentally talking about energy, which doesn't obey the rules all humans are accustom to. The world where we can't see it or relate it to our daily experiences but only talk about it through mathematics.

Re: Why does a spray bottle work?

#75

Post by akg_67 » Sat, Jun 09, 2018, 10:59 PM UTC

gxs wrote: post #47

MichaelApproved wrote: post #41

Earlier quoted context omitted.

Why isn't this in everything? I'd easily pay an extra few cents to have this in spray bottles. It's such a frustrating problem.

Jumping to the conclusion that everything a company does is calculated and delibarate is a mistake I see a lot of people make, but in this case it’s accurate. In a business that operates at a scale of 100s of thousands if not millions of bottles sold annually, cents matter and can make up a significant portion of revenue. With this in mind, there is a huge incentive to get people to buy sooner rather than later and m…

I am not sure why you were downvoted. There are several examples of the behavior you described.

Potato chip companies reducing the quantity of chips in a bag but keeping the size and price same. Because they were unable to raise prices with older packaging. Typically customers didn’t look at weight, just size of package. It was in the news for quite a while and IIRC there is a business case study.

It has been happening in beverages and other items too. Why do you see now package weights of odd numbers like 11.5 or 14.5 oz instead of standard number like 12 oz or 16 oz with typically no price reduction.

Recently I encountered same behavior with toothpaste tube in Japan. To keep the form/shape of the toothpaste tube with usage the nozzle was designed to suck in air to fill new space in the tube. My wife claimed we are out of toothpaste and wanted to throw away the tube. The toothpaste tube was perfectly formed but I noticed tube was still little heavier than I would expect for a empty plastic tube. But when you squeeze the tube mostly Air was coming out with little bit of spray of paste. Reducing the air space with paper clip, we were able to use paste from same tube for another 2 weeks. Typical behavior would be most probably what my wife was going to do to throwaway old one and open a new one.

Re: Why does a spray bottle work?

#76

Post by jimnotgym » Sat, Jun 09, 2018, 11:02 PM UTC

jarfil wrote: post #29

billsix wrote: post #13

Having source be in the "staging area" after "git add" makes more sense to me now :-)

I think this use of "staging area" comes from the military use, which in turn comes from the theater "staging", both predating git and the bottle.

I am not sure about the military use coming from the theatrical.

My understanding is that staging means 'standing place', and that the theatrical stage is just 'something to stand on'. You sometimes get scaffolding called staging in the UK.

The military use has the same root but is not derived from the theatre I beleive. A staging area is somewhere you stand and wait. Very similar in use to the staging-posts that a stage-coach goes through.

The meaning in git could mean directly this, somewhere to wait, or it could be derived from the further development of the process stages. The stage having become the journey itself rather than the stopping-point. Something is staged because you have completed a stage and are waiting to start the next stage. That is rather circular really.

At this stage I will pass you over to an article https://en.wiktionary.org/wiki/stage

Re: Why does a spray bottle work?

#77

Post by saagarjha » Sat, Jun 09, 2018, 11:02 PM UTC

If anyone's curious for more, look up how an atomizer works. It's simpler but requires more background knowledge (namely, the Bernoulli principle).

Re: Why does a spray bottle work?

#78

Post by trumped » Sat, Jun 09, 2018, 11:04 PM UTC

The spring might be the reason why a spray bottle doesn't last very long if you re-fill it with a bleach solution, when it was not designed for it?

Re: Why does a spray bottle work?

#79

Post by loopdoend » Sat, Jun 09, 2018, 11:05 PM UTC

ikurei wrote: post #67

vanilla-almond wrote: post #28

A few years ago, a British inventor appeared on a TV show called Dragon's Den (UK version of Shark Tank) and pitched his idea of an improved spray bottle called the Anyway Spray. Instead of a normal plastic tube inside a bottle with an opening at the end, he designed a tube with millions of tiny perforations along its length. This meant the spray bottle could operate at any angle (even upside down) and could empty al…

I wonder how the economic and environmental costs of the extra tubing (the tube in Anyway Spray bottles is longer than a straight, conventional one) compares to the costs of those few last drops for most sprayed products...

This improvement would cause the manufacturer to sell less product by volume.

Re: Why does a spray bottle work?

#80

Post by dredmorbius » Sat, Jun 09, 2018, 11:12 PM UTC

fjsolwmv wrote: post #60

richardfeynman wrote: post #52

Earlier quoted context omitted.

Michael Faraday gave a great series of lectures on how candles work that also illustrates the difference between cursory knowledge and explanatory depth. Most people think they know how candles work, but when you dive into the details there are all sorts of interesting things going on. https://en.wikipedia.org/wiki/The_Chemical_History_of_a_Cand... (you can also buy the lectures in book form on Amazon.)

Engineer Guy (a fantastic YouTube channel for learning how things work) has an audiovisual curriculum for this book. http://www.engineerguy.com/faraday/

That is indeed a wonderful recreation of a brilliant original, and I often think of it when trying to figure out how to provably and clearly demonstrate some absolutely novel concept. Faraday's genius shows through here.