DirtFarmer Loc: Escaped from the NYC area, back to MA

Guess what kind of flash was used? I suspect it would be considered a fire hazard these days.
(Original photo from archives of the Stow, MA Historical Society)

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Frank2013 Loc: San Antonio, TX. & Milwaukee, WI.

My guess is Red.

robertjerl Loc: Corona, California

You mean flash powder. Actually it is a low grade explosive.
In 7th grade I got a Sears chemistry set for Christmas that had the formula and stuff to make it.
That 50s chemistry set would get you a visit from SWAT and HazMat today. And it wasn't even their "Best" set, it was the "Better" set.

Remember when the sears catalog had three grades of everything, good, better and best? Often each made for Sears by a different company.

Uuglypher Loc: South Dakota (East River)

Yep! 7th grade Science Club! The Science teacher was also the Camera Club Adviser and got a kick out of the fact my dad had helped me make dry plates for our 5x7view camera, so it seemed a natural to make up some flash powder
from powdered Magnesium and a "smidgen" of...I'm thinking it was Potassium nitrate (?) for oxidizer. Set of in an angle iron holder with a spark gap from a D cell. Worked like a charm. Pulled the shades to dim the room, stopped down the old f/8 lens to a smaller aperture, practiced a few times removing the lens cap , getting a spark, and replacing the lens cap...and we were good to go! We started out with tiny amounts of the powder mixture and worked up to enough for a reasonable exposure. I'm guessing a teacher might loose his job over that project today!

Dave

robertjerl Loc: Corona, California

Being a retired teacher who had friends in the science department I can tell you it is worse than that.

Beyond some very basic things with "safe" stuff all the experiments are demos by the teacher, or, rarely, a star pupil or two, usually only helping the teacher. One college professor I know told me that even many college classes below the upper division are now the same.

And when I was in 9th I was one of the two students who worked the supply room in Sci class. The first week of school we found two quart bottles next to each other on a shelf. Glycerin and nitric acid. We moved one to a shelf on the far side of the room and quietly told the teacher what we had done. She had just been hired a few weeks earlier and didn't know someone had stored them that way. Two quarts, that would have made a significant boom.

Billyspad Loc: The Philippines

Nice umbrella my man

DirtFarmer Loc: Escaped from the NYC area, back to MA

Actually making nitroglycerin from glycerin and nitric acid is tricky. As I recall from the time we made it in high school (i.e. high school days, not actually in the school -- we did it on our own), the reaction is exothermic, so the stuff bubbles and spatters all over. You have to do it in a cooling bath. Otherwise the stuff decomposes as you make it so the yield is greatly reduced. (We did not make it in quart quantities).

Even in those far gone days we weren't able to get nitric acid easily so we had to make our own.

robertjerl Loc: Corona, California

It has been so long that I would have to look up the way to make it, but I do remember that you must add one of them slowly to the other. Do it in reverse or too fast and bad things happen.

DirtFarmer Loc: Escaped from the NYC area, back to MA

We had better luck making nitroglycerin than we did making corn whisky.

(And we did have a school project on fermentation but we didn't get to try any of the results).