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This is just priceless. I admire the breezy dismissal of potential harm/injury, and the confident reliance on exercising "reasonable care". Favourite (so far, t

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 lid of the tin. The finely divided flour has exploded. It is best to do this experiment out of doors. Not that the explosion is dangerous, but the lid might go through a window or do some damage in the room. It is also important to take care that the lid does not hit you in the face. Given reasonable care this flour bomb explosion is perfectly harmless.

timthorn 4y ago
I was reminded of this attitude last week, when I met a TV presenter from my childhood. He was known for doing daring things, the first of which was cleaning the Big Ben clockface. The Daleks were not the only scary thing on 80s BBC TV: https://www.bbc.co.uk/archive/blue-peter--big-ben-is-cleaned/z4s6kmn https://www.bbc.co.uk/archive/blue-peter--big-ben-is-cleaned...
genewitch 4y ago
Yes, a small flour puff can make a fancy show and is fairly safe, Mr. Wizard did it on his show decades ago. Then again, anything, when suspended in air in significant amounts and the right ratios, will explode. Sugar and flour explode just fine. Sawdust, metal particles, and don't drop that cup of flour next to an open flame if you like your eyebrows.
nibbleshifter 4y ago
Years back had a teacher who would use this demo to liven up the first class of the year. She would go on at length about how important studying science was, wait til everyone looked half asleep, then bang.
jhgb 4y ago
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.
- rflrob 4y ago
  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.
  - jhgb 4y ago
    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...
maire 4y ago
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 https://www.gutenberg.org/ebooks/12655 The Boy Mechanic, Book 2: 1000 Things for Boys to Do https://www.gutenberg.org/ebooks/44585 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.
- jonjacky 4y ago
  I recall seeing a book once called Science Experiments You Can Do At Home -- But Probably Shouldn't
- samizdis 4y ago
  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.
- jdougan 4y ago
  There was also The Boy Electrician https://www.gutenberg.org/ebooks/63207 https://www.gutenberg.org/ebooks/63207 My elementary school (1975) library had a copy I devoured.

timthorn 4y ago

I was reminded of this attitude last week, when I met a TV presenter from my childhood. He was known for doing daring things, the first of which was cleaning the Big Ben clockface. The Daleks were not the only scary thing on 80s BBC TV: https://www.bbc.co.uk/archive/blue-peter--big-ben-is-cleaned/z4s6kmn https://www.bbc.co.uk/archive/blue-peter--big-ben-is-cleaned...

genewitch 4y ago

Yes, a small flour puff can make a fancy show and is fairly safe, Mr. Wizard did it on his show decades ago. Then again, anything, when suspended in air in significant amounts and the right ratios, will explode. Sugar and flour explode just fine. Sawdust, metal particles, and don't drop that cup of flour next to an open flame if you like your eyebrows.

nibbleshifter 4y ago

Years back had a teacher who would use this demo to liven up the first class of the year. She would go on at length about how important studying science was, wait til everyone looked half asleep, then bang.

jhgb 4y ago

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.

rflrob 4y ago
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.
- jhgb 4y ago
  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...

maire 4y ago

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 https://www.gutenberg.org/ebooks/12655 The Boy Mechanic, Book 2: 1000 Things for Boys to Do https://www.gutenberg.org/ebooks/44585 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.

jonjacky 4y ago
I recall seeing a book once called Science Experiments You Can Do At Home -- But Probably Shouldn't
samizdis 4y ago
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.
jdougan 4y ago
There was also The Boy Electrician https://www.gutenberg.org/ebooks/63207 https://www.gutenberg.org/ebooks/63207 My elementary school (1975) library had a copy I devoured.