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Why does a spray bottle work?

alexanderellis.github.io

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Re: Why does a spray bottle work?

#61

I found his write-up on MBTA bus mirror positioning to be a short but interesting read as well: https://alexanderellis.github.io/blog/posts/mbta-bus/

From the map I can't tell how the bus can "go through Bennett Alley and continue straight into the bus tunnel". The streets are not aligned, are they?

[deleted]

Re: Why does a spray bottle work?

#62
post #27

Earlier quoted context omitted.

MONIAC [1] was an analog computer designed in 1949 that used water to model the national economy of the United Kingdom. 1. https://en.wikipedia.org/wiki/MONIAC

Made by an engineer turned economist from New Zealand no less. Sadly he is better know for a diagram he drew of an observation, the Phillips curve. I fear that much like this hydraulic model, Steve Keen's work is likely to be ignored or ridiculed by future economists while they fret over religious X diagrams.

Hydraulic models solve differential equations. They aren't bad , but modern computers are a much better computational environment.

Re: Why does a spray bottle work?

#63
post #27

One way valves are basically diodes, but for fluids rather than electrons. You can also make logic gates out of just diodes (or one way valves). Imagine writing software for a hydraulic computer!

MONIAC [1] was an analog computer designed in 1949 that used water to model the national economy of the United Kingdom. 1. https://en.wikipedia.org/wiki/MONIAC

Did all the banks have their own taps?

https://bankunderground.co.uk/2015/06/30/banks-are-not-inter...

Re: Why does a spray bottle work?

#64
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.

The analogy is valid and hydraulic circuits work.

If people transfer their incorrect understanding of water to incorrect knowledge of electricity, that doesn't make the analogy bad.

Re: Why does a spray bottle work?

#65
post #25

Earlier quoted context omitted.

That diagram at the top of the Wikipedia article made the concept more clear to me than the whole orginal post. Drawing the valves like that really helps. Edit: grammar

That's funny, I don't know what that diagram is trying to convey.

Your confusion is understandable, since the Wikipedia article doesn't even make the slightest attempt to explain the diagram.

So let me try. Let's start with the piston pump on the left. The brown piece moves up or down in a tube, and the two black "T" figures are valves that open or close in response to water pressure.

The down arrow next to the piston indicates that the piston is currently moving down and pushing on the water. This causes the valve at the bottom to close and the valve on the left to open. So water comes out at the top left.

After the piston is pushed down as far as it will go, you start pulling the piston back up. This is not shown in the diagram, but now everything is reversed. The valve at the left closes, and the valve at the bottom opens, both in response to the pressure change.

So now, water is pulled up from the well or other source, filling the chamber. When it is full, you start pushing down again, and the cycle begins anew: the valve on the left opens and the valve on the bottom closes, pushing water out of the spout at the top left.

Once that makes sense, take a look at the plunger pump on the right side of the diagram. You will see that it works on exactly the same principle: when you move the brown part up or down, it pulls or pushes on the water in the same way as the piston pump. The only difference is in the shape of the moving part.

Re: Why does a spray bottle work?

#66

This is a nice example to show the illusion of explanatory depth [0]. Most people would say they know how a spray bottle works, but fail to describe all relevant details of the implementation, [0] https://www.edge.org/response-detail/27117

I think how trains stay on tracks [0] is also a good example of this.

[0] https://www.popularmechanics.com/science/a25581/science-behi...

Re: Why does a spray bottle work?

#67

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...

Re: Why does a spray bottle work?

#68
post #39

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…

Seems like he managed to license it to Tesco's range of label products. Good for him.

Good for us! :)

Re: Why does a spray bottle work?

#70

Earlier quoted context omitted.

That's funny, I don't know what that diagram is trying to convey.

Your confusion is understandable, since the Wikipedia article doesn't even make the slightest attempt to explain the diagram. So let me try. Let's start with the piston pump on the left. The brown piece moves up or down in a tube, and the two black "T" figures are valves that open or close in response to water pressure. The down arrow next to the piston indicates that the piston is currently moving down and pushing o…

The most recent AvE video had a break down of a pressure washer which includes an explanation of a piston pump. https://youtu.be/4IbjQyR9X6E
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