Daddy
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Posts: 26
Registered: 13-3-2009
Location: Peru
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Introducing myself (Why I am here)
Hello everyone,
I thought I best start posting by telling some things about myself.
Actually I decided to participate here because of my kids (9 and 11 years old). They want to learn some chemistry and do some experiments at home. So
I had to start learning myself, since I had not done anything related to chemistry since my school years. Now the memories are coming back and we
started our small laboratory at home and did some simple experiments.
We live in the Peruvian Highlands, and chemicals can not easily be bought here. We started with baking soda, glass cleaner, vinegar, alcohol, muriatic
acid, iron filings, copper wires, galvanized iron wires, lime, some fertilizer (ammonium nitrate and potassium chloride), and an acid-base indicator
made from turnip peelings; that was about everything.
Then we found also some sulphur and some copper sulphate at the market stall of some witch doctor. It really seems we are getting back to the old
times when chemistry was an esoteric pratice reserved to alchemists and the like... You cannot get ammonia solution nor caustic soda here (I did not
even find any as an ingredient of household cleaners), except if you have a registered company. (You can get bleach, though.) Now thanks to this forum
I found information about how to make ammonia from fertilizers and caustic soda from baking soda, so we have now these too. - You cannot get sulphuric
acid officially; you have to take apart a car battery or find someone who does it for you. I went to uncountable hardware stores and electrical supply
stores looking for zinc and magnesium, without success. It was a great day when my wife found aluminium foil in one of the largest stores of the city
(this was an unknown item here not long ago), so we have now aluminium at least, and we can make hydrogen reacting it with muriatic acid. (Although we
were warned that sale of muriatic acid will soon be forbidden.)
OK, there are some other items we have, but which I did not yet use for anything: iodine tincture, hydrogen peroxide, magnesium hydroxide, acetone
(not pure).
So our kids are having fun mixing different substances and looking at how they react (under my guidance, of course), and testing everything from
vinegar to milk to the cat's hairs for seeing if it is acidic or basic, and things like that, while I am trying to explain the reactions to them.
There are some things I do not understand, and so I think of coming to this forum from time to time, asking some stupid (or not-so-stupid) questions
and hoping to get some answers.
However I do not spend much time connected to the internet, so I might not be quick to respond, just pop in from time to time.
And I thank you all for the useful and interesting information already posted on this forum.
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watson.fawkes
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| Quote: | Originally posted by Daddy
We live in the Peruvian Highlands, and chemicals can not easily be bought here. We started with [...] lime [...] |
Calcining and slaking lime is my favorite introduction to conservation principles. There's calcium behind the scenes, revealed
through a cyclic transformation. Start there, and make some other calcium compounds. This kind of activity gives experience in what the concept
"chemical element" means, and in such a way as to spark further curiosity.
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ProChem
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Registered: 9-6-2008
Location: Union Beach, NJ. USA
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welcome daddy:
When I was in eigth grade I learned that you can produce methane, methanol, wood tar and charcoal by the destructive distillation of wood. What you
need for this experiment is a few tooth picks, burner, test tube, one hole stopper, a length of glass tubing bent to 90 degrees (e.g. 150mm tube bent
50mm from an end) with the short end through the stopper into the test tube. Place the toothpicks in the test tube, insert the stopper and tube.
Heat the contents and observe the smokeand when it exits the tubing touch it with a lit match. The gasses will light and stay light until the heat
source is removed or the wood is depleted. The liquids on the cool parts of the tube are wood alcohol, water, light oils and the tar is the sticky
resin. Finally the charcoal is what remains. You can use the charcoal for other experiments in the future.
Regards
ProChem
[Edited on 13-3-2009 by ProChem]
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woelen
Super Administrator
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Registered: 20-8-2005
Location: Netherlands
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Daddy, also a welcome from me! Good to see people over here who are eager to try things, while having only very limited resources!
Another experiment which may be interesting for you is the blue copper/ammonia complex. You have all items, needed for that.
Take some 10% muriatic acid (10 ml is enough), then take two copper wires and connect these to a battery (or DC power adapter) and immerse the copper
wires in the acid. Gas will be produced at the cathode (negative pole) and the anode dissolves. If you use an AC-non-rectified power source, then both
wires dissolve and gas is produced at both wires. Do this for a while, such that quite some copper has dissolved. You will obtain a nice green
solution with copper-chloro complex.
Now add ammonia (you told that you can make this now) slowly. First you get a precipitate which redissolves on swirling as long as there still is
excess acid, but at a certain point the precipitate will not redissolve anymore. But if you add much more ammonia, then the precipitate redissolves
again. Now a beautiful royal blue color is obtained! This blue color is due to a copper-ammonia complex.
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Daddy
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Posts: 26
Registered: 13-3-2009
Location: Peru
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Thanks a lot for your suggestions!
We had already produced the copper/ammonia complex, by simply adding ammonia solution to a CuSO4 solution. I think I even got the idea from your
website, woelen. (There is a lot of interesting stuff there! Only that some of those experiments are too dangerous to do them with kids...) My kids
loved the color changes.
We did not yet do anything related to electrolysis, but I think we will start with it next month and then I will certainly use this suggestion as
well.
ProChem - interesting idea too. Only that I could not get any glass tubes so far; this is odd since we found a place where most usual glassware is
sold, but no ordinary tubes... will a plastic or rubber tube do? or does it get too hot? (or else I might try with some iron tubing, but I do not have
bent ones, so I would still need some plastic or rubber to make the bend.)
And about lime, yes, we already used it for several experiments. One of them should have yielded calcium nitrate, and one of the books in the library
here (the one by Roscoe and Schorlemmer) says this compound is phosphorescent after heating and exposing it do direct sunlight. I tried this, but it
did not work; maybe it was not sufficiently pure? or the book is wrong? (I could not verify its claim from any other source.)
We also tried calcining limestone inside a wood stove such as is still used in rural areas for cooking; but it seems that it did not achieve
sufficient heat. Only at the surface of some of the stones appeared a thin white coating which I suppose is CaO; the rest remained unchanged.
What my kids liked most so far was filling a balloon with hydrogen. Only that I had to be behind them all the time so they would not take it to a
place where it might explode.
[Edited on 20-3-2009 by Daddy]
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