Inkwell: Authors and Artists

    
Hi Rockyshoe! I'm so glad you and your kid had fun with the book. My
daughter never gets tired of making slime (and neither do I). I found a
great new substance to mix with the borax solution - liquid starch. You get
a "dry" slime from it.

Mark, I do most of my drawing on the computer. It's just so dman convenient.
I love being able to swap colors around. Sometimes I'll start with a pencil
sketch and then scan it and trace over it in Illustrator using my Wacom
Graphire tablet. I don't often go into photoshop. I use Image Ready to
convert Illustrator files into jpgs and gifs for web work.
  

    
I liked that you named the cornstarch goo "Robot Food," Mark.

What a strange substance that is.  When I was about 11 years old, I spent my
summers in the Sierra Nevada where my dad ran a climbing school.  He had a
lot of interesting grownups for students, but most of them ignored me and
my sisters.

So the big challenge was to figure out things to amaze them -- yet not
annoy our parents.  

One of my favorites was when we mixed up some cornstarch -- er, Robot Food 
sans food coloring -- in a Sierra Club cup and breathlessly presented it
to one of the climbers, saying we had found it oozing from a crack in the
granite where there was a dark stripe. 

He played with it for a good 15 minutes, fascinated and puzzled, and asked
us additional questions.  Then one of the few women students happened by
(this was the late sixties, when adventure sports were still
overwhelmingly male) and took a look.  She knew immediately, and busted
us, somewhat slyly, by saying "making gravy, girls?" 

I have a request, for the sequel.  Someone gave me a copy of a homemade
household cleaning formulas book, and I realized that a slightly older kid
might find the removal of silver tarnish by use of water softener and
aluminum foil, etc, magical or scientifically instructive, too.
It sure had me wondering.
  

    
Great story, Gail! Please tell me how to remove silver tarnish using your
magical method. My wife found an old silver dollar in a box and it is almost
black. We'd love to make it shiny again.
  

    
The request for a sequel from my five year old, Gabe, is one using outdoors
stuff, mud, branches, plants, water, seeds.  Not that he doesn't want to
make a Martian Volcano everyday, mind you.
  

    
must know how high the film canister is supposed to explode. 
  

    
Maybe you need a tighter lid that lets more gas pressure build up
before popping. I haven't tried this one. I wonder if a Fuji film
cannister is better than Kodak. Mark?

I'd have to say the book's  9-12 age designation is more of a
guideline (perhaps erring on the side of caution).  It looks like
younger kids can enjoy the projects safely with adult supervision. What
do say, Mark? You credit your daughter, Sarina, with helping out with
"honest feedback." Were there some experiments she poo-pooed?
  

    
my lab partner has the flu, so though I did buy borax and white vinegar for
us, we haven't gotten back to experimenting.  hopefully next weekend.

not sure if this is what Gail does, but I saw someone hawking a home
cleaning book on TV once and they cleaned silver with a solution of warm
water, salt and washingi soda, in a pan lined with aluminum foil.  Have used
that method a few times, winging the proportions and it works great.
  

    
Yeah, that's it.  By a guy named Haley.  I'm no cleaning wiz, but I got 
that book as a sort of geeking household joke gift.  I really want 
to know the science of this:

place a sheet of aluminum foil on the bottom of a sink or pan
1 qt hot (not burning hot) water  (enough to cover silver) 
1 Tbsp water softener/washing soda   (he notes that if you are in europe 
             this is not what is called "washing soda crystals" over 
             there -- which could do damage to silver)
1 Tbsp salt

Place the silver in for 10 seconds, be sure all silver peices touch the
foil and are fully covered by water.  Remove, buff with a soft cloth.

(On the web you find variants saying that you have to use a pan, and
boil the silver and all for 2 minutes, but that doesn't seem to be 
the case.)

There's an article on care of valuable raised pattern silverware, etc,
at http://doityourself.com/clean/silver.htm
mentioning this method with the boiling directive.

The Haley book says to not use it with anything with stones set in it.
The setting could loosen. (I'm guessing that's with glued settings only
but he doesn't say).

I have a bunch of questions.  What's the chemical colution from salt and
water softener/washing soda?  How does the electrolytic process work (I
think that's the term.)  

Why are other folk methods polishing with either salted lemon juice or a
baking soda solution, since one is acid and one base?  

Why do you damage silver if you put it in the dishwasher touching
stainless steel?

It's all a mystery.  But dipping into that bath and touching the foil is
very cool.
  

    
OK, I finally did the logical thing and asked in the Science conference.

Great answer, I'll paraphase the points.  I hope the poster drops by 
over here too.  

This experiment creates a weak battery 
the NaCl/Na2CO3 is the electrolyte, 
and the dissimilar metals are the electrodes.  

The oxidized silver tarnish is being reduced 
and the more reactive aluminum is being oxidized

If enough spoons were cleaned, eventually the 
aluminum foil would disappear.  The aluminum is 
providing electrons to the silver.  

If you cleaned enough silver there would be a 
white precipitate of some kind of aluminum 
hydroxide or carbonate precipitate ... 
(maybe we can figure out what that would be).

<science.564.133>
  

    
Obviously that's for older kids, but the idea that you are making a battery
to clean coins, spoons or necklaces is pretty cool.
  

    
That is interesting. And thanks to (jetpack) over in the science conf.
I know little about chemistry. 
  

    
Thanks Gail! I guess you can buy water softening powder at any supermarket?
  

    
Did a little more poking while on the phone on hold.  The key thing 
is getting the right chemicals.  
From http://www.steamengine.com.au/ic/faq/electrolysis.html

>Pure sodium carbonate is called soda ash, and is very dangerous because 
>it will boil water when mixed with it, and even make a steam explosion. 
>Washing soda is the hydrated form of sodium carbonate (called sodium 
>carbonate decahydrate, it has TEN water molecules attached to one 
>sodium carbonate molecule!), and is 5/8 water by weight even though
>it is a dry powder. The product you found at the store labeled as 
>detergent is not washing soda, although it has some in it.  Washing soda 
>is a mixture of mostly sodium carbonate decahydrate with some sodium 
>sesquicarbonate and sodium bicarbonate in it. Go to the grocery store
>or supermarket and read the labels on the washing supplies for walls and 
>floors. Washing soda is sold under the names of stuff like Spic 'N Span, 
>TSP Brand washing compound, and 20 Mule Team washing soda (not borax). If
>you can't find anything that is 90%-100% washing soda (sodium carbonate 
>decahydrate) and/or sodium sesquicarbonate, just get some plain old Arm & 
>Hammer baking soda. Take 0.6 times (about 5/8) as much baking soda as 
>the amount of washing soda called for in the electrolyte recipe,
>add just enough water to make it soupy, heat it for a few minutes while
>it fizzes, then add it to the rest of the water. Baking soda is 
>sodium bicarbonate, which decomposes with a little heat and water into 
>carbon dioxide gas and sodium carbonate decahydrate.
  

    
However, I think either washing soda or water softener would be in the
laundry aisle.
  

    
A new discussion has launched featuring Cory Doctorow (who's a prolific 
blogger via the bOING bOING blog that Mark F. created). Mark and Mark, 
I wanted to thank you both for bringing us this cool discussion, and let 
you know that you're welcome to continue!
  

    
Thanks Jon. And thanks Mark.