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The Book of Experiments (1958) [pdf]

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Re: The Book of Experiments (1958) [pdf]

#31

Post by rflrob »

jhgb wrote: post #25
samizdis wrote: post #4

This is just priceless. I admire the breezy dismissal of potential harm/injury, and the confident reliance on exercising "reasonable care". Favourite (so far, that is): 26. A flour bomb as a noisy finale to our air experiments ... If you tried to set fire to a small heap of flour you would not succeed. But finely divided flour in a cloud—that can make a completely harmless bomb! ... With a great BANG! off flies the l…

I'm surprised by the writer completely ignoring the possibility of blast injury to the lungs...? Blowing into a hose connected to a space in which an explosion takes place would worry me much more than what the lid might do.

My naive assumption is that there’s a combination of two factors going on: 1) the blast force will be proportional to the area through which it’s transmitted, and a narrow hose will have a lot less area than the lid of a can, and 2) if the hose is fairly flexible rubber, there will be significant reduction of the force over the length of the tube.

Re: The Book of Experiments (1958) [pdf]

#32

Post by jhgb »

rflrob wrote: post #31
jhgb wrote: post #25

Earlier quoted context omitted.

I'm surprised by the writer completely ignoring the possibility of blast injury to the lungs...? Blowing into a hose connected to a space in which an explosion takes place would worry me much more than what the lid might do.

My naive assumption is that there’s a combination of two factors going on: 1) the blast force will be proportional to the area through which it’s transmitted, and a narrow hose will have a lot less area than the lid of a can, and 2) if the hose is fairly flexible rubber, there will be significant reduction of the force over the length of the tube.

All of these things are possible, but personally I'd just never risk it by assuming that the pressure wave will escape "somewhere". Call me a coward, but still...

Re: The Book of Experiments (1958) [pdf]

#33

Post by maire »

samizdis wrote: post #4

This is just priceless. I admire the breezy dismissal of potential harm/injury, and the confident reliance on exercising "reasonable care". Favourite (so far, that is): 26. A flour bomb as a noisy finale to our air experiments ... If you tried to set fire to a small heap of flour you would not succeed. But finely divided flour in a cloud—that can make a completely harmless bomb! ... With a great BANG! off flies the l…

If you like this, then you will love this 1913 Boy Mechanic series.

The Boy Mechanic Volume I: 700 Things For Boys To Do https://www.gutenberg.org/ebooks/12655

The Boy Mechanic, Book 2: 1000 Things for Boys to Do https://www.gutenberg.org/ebooks/44585

One of the transcriber said: Another class of projects illustrate the caviler attitude toward environment and health in 1913. These projects involve items such as asbestos, gunpowder, acetylene, hydrogen, lead, mercury, sulfuric acid, nitric acid, cadmium, potassium sulfate, potassium cyanide, potassium ferrocyanide, copper sulfate, and hydrochloric acid. Many references to these have been highlighted in red.

Projects requiring extra skill and care that involve high voltage, melting metals, or other hazards, have the title highlighted.

Re: The Book of Experiments (1958) [pdf]

#34

Post by VLM »

pvitz wrote: post #21
Stratoscope wrote: post #8

These are wonderful. Let me add one of my own to the collection. This is a true story from that same era, maybe a couple of years later when I got kicked out of my third grade class for being a troublemaker and had to go to a special ed class called Mrs. Spencer's Workshop. 199. Make your own printed circuit board You will need: a common kitchen cutting board, a sheet of copper, a roll of electrical tape, a fish tank…

Thanks for your story! I am wondering why your teacher would use nitric acid. Wouldn't iron(III) chloride have been much safer in a workshop with children?

WRT safety its probably a taste thing.

Diluted enough, the nitric could easily be made weaker than your stomach acid but will still eventually dissolve the copper. Its a sort of linear-ish relationship of concentration vs time so you can trade safety for time (as with most industrial processes, LOL)

I would think dilute iron chloride would not taste good, but you could probably chug enough to get sick.

I believe there would be a similar relationship WRT staining skin and clothes, dilute enough HNO3 would not be TOO much more dangerous than letting kids handle a can of Mt Dew unsupervised, but FeCl in any dilution will stain and damage clothes and skin.

If I had to work with maximal concentration solutions of both, I'd agree and definitely prefer the conc FeCl vs fuming nitric.

Re: The Book of Experiments (1958) [pdf]

#35

Post by VLM »

13of40 wrote: post #26
zabzonk wrote: post #7

Earlier quoted context omitted.

My own worst experience with fire was with a Primus stove ( https://en.wikipedia.org/wiki/Primus_stove ) when I was about 14. I'd squirted the priming meths alcohol from a squeezy bottle on to the stove and lit it. But then (because alcohol burns with a near-invisible flame I thought it had gone out, so I squirted more on, then ... boom! Squeezy blew open, sending burning meths everywhere. Luckily alcohol doesn't bur…

When I was about 13 years old, a retired engineer (slash wizard) who was friends with my mom gave me a 25,000 volt step-up transformer. Why any adult would do that is beyond me, but I was always very safe with it and managed to do a lot of cool experiments without killing myself. I let my friend borrow it, though, and his brain was calibrated a little bit differently as far as risk behavior, etc. He ended up shocking…

Probably a neon sign transformer. The tube won't ionize until tens of thousands of KV but when it does light off, the resistance of the plasma drops to practically nothing compared to the excellent insulator it is when not ignited. Neon tubes are negative resistance devices, 25KV at zero current vs maybe 10 mA at 300 V after it ignites is a resistance of negative 30K or so. The point is a lot of EE work goes into the magnetic design of the transformer such that it current limits to some specified value. If you use a core material and shape that'll saturate at 10 mA but a ratio of number of turns such that it'll output 25 KV as long as the current is roughly zero, that would make a good neon sign transformer.

Much like alcohol there is no minimum safe harmless amount of current thru the heart, but if you have what by neon transformer standards is a very low current transformer, like limited to 5 mA or so, that might be a low enough current to only kill like 0.0001% of the population or whatever. A kid will probably be fine. An old person with heart problems, maybe not so much.

Re: The Book of Experiments (1958) [pdf]

#36

Post by oh_my_goodness »

daniel-cussen wrote: post #3
zabzonk wrote: post #2

Some good stuff, but also stuff like this, from the Cartesian Diver": > Air is easily compressible, water is not. Not significantly compressible, in the sense of reducing volume, but it is pressurisable (think of pressure at the bottom of the ocean), which is what this experiment depends on. > The water is not compressed by your called ions) and the chlorine atoms (chlorine ions) of which the salt in solution consist…

I think playing with fire is a basic part of being human. Humans, fire. The fire primate, why we don't have hair or fat for body heat, we have fire and clothes. Like how else are you going to learn but seeing what happens if you eg play with the gauge on a lighter (for education, playing is mostly about learning), more flame, less flame, look at it, marvel at it. Doesn't mean getting burned though for sure there will…

We don't have much hair because we'd just keep burning it off anyway.

Re: The Book of Experiments (1958) [pdf]

#37

Post by BrandoElFollito »

I had an older professor of physics at the university (I was studying physics) - he was a theoretician. Once a year he felt the need to make an experiment "for completeness".

As good as he was as a theoretical physicist, he was a walking disaster with experiments.

In mechanics there is an experiment where you sit on a chair, with weights in your hands, someone makes you spin and then you extend the arms and the movement is slowed down (conservation of momentum if someone is interested).

He wanted to show this, sat on a chair, extended his arms and asked a student to spin him fast. And then retracted his arms next to the torso. He flew two or three meters away from the chair and fell down, with us jumping to help him (he was something like 70 at that time).

After getting back to his senses he continued with an experiment where you hold a bicycle wheel in your hands by the axis, it spins quickly and you cannot flip it right or left. So he did.

And then he was left with a spinning wheel in his hands, wondered a moment what to do with it and simply dropped it on the floor. It is amazing he managed to squarely hit the audio system of the amphitheatre which did BOOM and we did not have sound anymore.

That was the end of the experiments for that year.

Re: The Book of Experiments (1958) [pdf]

#38

Post by BrandoElFollito »

When I was visiting Poland, some friends told me that they had, as kids, a TV show where a man was discussing how to build stuff.

He would start with a set of wires, some wooden tablets, a few screws and a piece of paper. He would draw how "we" would build, say, a house out of this, moved the pieces around and suddenly was getting from below the table some incredibly complex construction they were supposed to easily reproduce :)

Re: The Book of Experiments (1958) [pdf]

#39

Post by samizdis »

maire wrote: post #33
samizdis wrote: post #4

This is just priceless. I admire the breezy dismissal of potential harm/injury, and the confident reliance on exercising "reasonable care". Favourite (so far, that is): 26. A flour bomb as a noisy finale to our air experiments ... If you tried to set fire to a small heap of flour you would not succeed. But finely divided flour in a cloud—that can make a completely harmless bomb! ... With a great BANG! off flies the l…

If you like this, then you will love this 1913 Boy Mechanic series. The Boy Mechanic Volume I: 700 Things For Boys To Do https://www.gutenberg.org/ebooks/12655 The Boy Mechanic, Book 2: 1000 Things for Boys to Do https://www.gutenberg.org/ebooks/44585 One of the transcriber said: Another class of projects illustrate the caviler attitude toward environment and health in 1913. These projects involve items such as asbes…

Wow. Just sublime. Insanely ambitious projects mixed with the insightfully practical and leavened with, er, just so many ways to die. Have downloaded both and will relish reading them thoroughly. Many thanks.

Re: The Book of Experiments (1958) [pdf]

#40

Post by djmips »

gdsimoes wrote: post #20
samizdis wrote: post #6

Has anyone tried this? 131. Cut glass with. .. scissors! You will need: bowl of water, pair of scissors, piece of glass. It is possible to cut glass with ordinary scissors in any shape you wish, provided that while cutting you hold the glass and the scissors as well as your hands completely under water. The water deadens the vibrations which make the glass crack. Yes, under water, glass can be cut almost as easily as…

I found this video of some guy doing it: https://m.youtube.com/watch?v=tEAxhMECluM

I'm pretty sure that guy has a copy of this book as he demonstrates a bunch of these experiments on The Action Lab. ;-)
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