Yehoshua Sivan, Safed 13400, Israel
Demonstration 2
Observe a wire gauze lowered onto a cool flame. If you happen to look from above, you possibly can see that the flame is hole.
Because the gauze heats up, a flame reappears above it. College students finally recommend that the centre of the flame comprises unburned gasoline, and college students might finally recommend a check akin to this:
Demonstration 3
One other attention-grabbing little experiment is to warmth a thick piece of copper in order that it blackens on eradicating it from the flame (CuO is shaped); on placing it again within the flame, the shiny pinkish color reappears on the floor so long as it’s within the flame, however on withdrawing it, it turns black once more. This impact outcomes from unburned hydrocarbon gasoline (for instance, butane) reacting with the oxide by the next response:
13CuO(s) + C4H10(g) → 4CO2(g) + 5H2O(g) + 13Cu(s)
Demonstration 4
If you happen to thrust an unburned match into the middle of the “cool” (luminous) flame, the a part of the match within the middle doesn’t ignite, whereas the wooden does burn! A burning match is extinguished when the pinnacle is put into the center of the flame!
Demonstration 5 – “magnesium and fire”
The scholars are at all times inquisitive to know what half the holes play in figuring out the flame shade and warmth. The drawing under illustrates a quite simple means of displaying that air is being drawn in (some college students had thought that if the holes have been opened, gasoline would come out). There’s room for additional dialogue right here (aside from the Bernouilli impact per se), relating to the altering shade of the flame. Much less air goes in, if the combustion merchandise of the match take its place.
I printed a riddle regarding the Bunsen burner flame in Chem13 Information, February 2001, web page 4.*
Observe
*Each of the riddles talked about by Yehoshua can be posted on-line underneath “Supplemental materials” on the Chem13 Information web site.
Extra about February 2015