That book was one of my favorites. It was apparently banned from school libraries but was available all when I was a child.
12 ounces of lye granules cost less than 50 cents back then. I purchased my own rolls of aluminum foil as well. The problem with using a strong lye solution is that the reaction is exothermic and gets hot enough that enough steam can be created that the balloons do not float. The solution was to keep the mixture diluted enough that the foil was not consumed so quickly or to just let the bottle cool down if it got very hot.
In one of my junior high science classes I demonstrated filling balloons with hydrogen. The teaches had been using sulfuric acid and galvanized nails to produce hydrogen for his demonstrations. I considered this an inferior method.
The teacher's lab assistant who was not known for his intelligence, took one of the small balloons that I had filled and lit it on fire while holding it in his hand. When you do this, it just makes a woof sound as the hydrogen catches on fire. Although, hydrogen is much lighter than air and the flames go up I was not aware that doing this would not result in getting burned with a small balloon.
This all seems very funny to me now because I am fairly certain that the activities that my science teacher demonstrated to us would likely get him in trouble these days. I liked him a lot and took summer school classes from him because he tried to find activities that not only were informative but also captured our interest.
My high school chemistry teacher treated us to some interesting experiments. We made isoamyl acetate (banana oil) from vinegar and isoamyl alcohol. We made oil of wintergreen (methyl salicylate) from methyl alcohol and salicylic acid. We collected red rust and aluminum cans and ground them into a powder that we lit with a strip of magnesium to create steel with a thermite reaction. A small volcano was created with potassium permanganate and glycerin. A very exothermic burn of sugar and potassium perchlorate. Contact explosive (ammonium nitrogen tri-iodide). It was an amusing class. I read the class text and did every exercise in the book in 3 1/2 weeks because I transferred from the band to chemistry 9 weeks into the year. It was an easy A and good preparation for UCSD later.