One of my daughters had the following assignment for science. First you boil a couple leaves of red cabbage and pour off the water. In our case the water was inky blue, but the results may vary according to your water chemistry and possibly by your cabbage. Next add a little diluted ammonia to the water and the color will change. Add the right amount of vinegar and it will change back to the original color. Add more vinegar and it will turn a new color. The liquid can turn a wide spectrum of colors. (Which colors? You’ll need to do the experiment to find out!)
Now we’ve got a jug of ammonia left over. What can you do with a jug of ammonia? Any practical uses? Fun uses? Any more science demonstrations?
Pour a little into each of your garbage cans to discourage the bears.
It was suggested to me, by my somewhat unscrupulous uncle, when I was a young boy to mix the household ammonia with iodine(solids). This, it was explained to me, would produce a paste that could be thinly spread on the jam of a door, or along the bottom rim of a mug – that would explode when an unsuspecting fellow happened across it.
You can find out more by following this link (Nitrogen Triiodide)
http://www.armory.com/~spcecdt/pyrotech/ni3_dir.html
Hi John
You have great site that I always look forward to reading.
There is another great site – The Naked Scientist, which has a slot each week called ‘Kitchen Science’. There they have details on experiments along the lines of your daughters homework.
http://www.thenakedscientists.com/HTML/content/kitchenscience/
A tip from a chemist friend: don’t mix ammonia with bleach. Doing so releases poisonous chlorine gas. That’s why you have to be careful mixing certain household cleaners.
The best use I’ve found for dilute ammonia solution is to loosen up burned-on crud on grills, etc. It’s the fumes that do it. Method is to put all your stuff to be cleaned in a plastic garbace bag, set a small amount (half cup) of ammonia solution in the bag, close the bag and leave it overnight.
Sal ammoniac is mentioned in the earliest alchemical work I know of. I recall a recipe to make it but there must have been uses for it.
The best ammonia experiement I know involves the gas.
You could probably find some fun experiments by googling for “chemistry magic trick ammonia”.
Regarding natural ph indicators, I always used baking soda or dilute lye/drano as the basifier, except for the blueberry pie a’ la mode:
Blueberry pigment like most natural organic pigments acts as a ph indicator by changing color. In a regular pie, the filling is acidic enough to make the pigment a bright reddish purple. Mix the filling with a little melted ice cream, and the ph is lowered enough to change the pigment to a dark blue-ish purple. Then you can break out the vinegar and baking soda.
Another interesting experiment is to examine how pigmented food items react to ph changes. Artifical colorings tend not to change color, while natural ones tend to do so. For example, do cheaper liqueurs tend to use artifical coloring to mimic the natural color of their more expensive counterparts?
A warning about nitrogen tri-iodide: It is extremely unstable when dry. Extremely!!!! Even a slurry of crystals and solution is stable but when dry watch out. The good news is you probably won’t have enough to do real damage, but once it is dry you can’t even touch it. A fly landing on it, a dry filter paper floating gently to the ground, etc. are all way too much disturbance. Plus, there are the stains. If you MUST play with it, keep it wet, preferably in solution and be aware that crust can form around edges and rims and in / on nozzles. Apply it as a solution and allow to dry. Dispose of the solution when done; if you store it and it dries out you are in a fix.