Oh, hey folks, my name is Julie. I'm from the Ontario Science Centre.
Just trying to clean up some of my metal
artwork here. Early alchemists used to think that
we could convert metals from one to another and create gold.
What if we could control metal reactions using our knowledge of electrochemistry
to create art and to protect metal objects that we use in everyday life?
We can take control of electrochemical reactions to create some beautiful art
with metal etching. I'm going to use this metal water bottle because I think it
would be really cool to personalize it. To do metal etching,
we'll need a metal object, vinegar, salt, a measuring cup,
something to stir with, a small shallow cup, a tablespoon,
cotton swabs, scissors, exacto knife, pliers,
a nine volt battery, electrical tape or duct tape, anything waterproof,
sandpaper, protective glove, a source of electrical wire, which could be reused
home wiring, a broken USB or broken headphones, and
some kind of clip, First, let's mix our electrolyte solution
by measuring a quarter cup of vinegar and adding to that two teaspoons of salt.
Stir to mix and transfer to a shallow dish so that your cotton swabs can be dipped easily.
Now we're going to make the circuit for our metal etching.
We'll need our 9-volt battery. I'm going to strip the plastic sheathing off the
ends of two pieces of wire and then hook them around both terminals
of the battery, covering them with electrical tape.
This prevents the chances of a short; you never want to connect two wires
to two terminals of the battery without a load.
Next, we're going to connect our cotton swab to the negative terminal of our
battery. I'll do this by hooking an end in
the wire and putting the swab in, possibly connecting with a clip if
needed to keep it secure.
The last step to get ready for our metal etching is to create a stencil for the
shape that we want to etch onto our metal object.
You can use any waterproof tape for this, duct tape or electrical tape,
and we're going to create layers of the tape on a cutting mat
and then cut out the shape using an x-acto knife.
After that, we will sand lightly sand our metal object
and transfer our stencil to the metal object. Then we'll be ready for plating.
To get ready for etching, we're going to take the wire connected to our positive
terminal and tape it to our metal object.
Then we're ready to start dipping our swab into our solution
and pressing it to our metal object. I brought my etching outside, because as
I started to do it, I noticed that I've had a faint smell of chlorine
and that's not really safer to inhale, so
I've decided it's safer to do this in a well-ventilated area.
Let's take a closer look at what's happening in our electric etching.
The positive terminal is connected to our metal object
and the negative terminal is connected to our swab
soaked in electrolyte solution. On the metal object we have
iron atoms at the surface. When we connect the positive terminal
to the iron atoms, it attracts electrons and pulls them through the wire
and out of our metal surface. This leaves behind
a positive charge on the iron atoms at the surface.
This creates a reaction where iron loses electrons to become positively
charged iron ions. This is an oxidation reaction
and we label this side of the cell the anode. At the negative terminal,
electrons are repelled. The electrons build up a negative charge
in our swab. This attracts the iron ions that we've created
and pulls them out and dissolves them in
the swab solution, leaving behind a gap
which creates the etching. We know that
there's also electrolyte solution in the swab. Something you may have noticed
is bubbles of gas at the swab. This is caused
when the negative electrons building up in the swab
react with the hydrogen ions in the acid solution.
The hydrogen ions and electrons joined together to form hydrogen gas.
Altogether in this electrolytic cell,
where we have an anode at the positive terminal
and a cathode at the negative terminal, we have created a redox reaction.
In a redox reaction we have both a reduction and an oxidation.
In this case, the hydrogen
gains electrons to become hydrogen gas and is reduced.
The iron loses electrons to become iron ions
and is oxidized. I like this etching result I got on my metal water bottle,
but iIm also excited to experiment with more electrochemistry art.
I've set up this circuit just the same as we used with our metal etching
to electroplate, where instead of removing a metal
i can add a metal. In this case, I'm trying to add copper
to another metal object and I'm using plant fertilizer as my electrolyte,
because I looked at the label and found out that it contains copper.
What metals do you think could be plated with copper?
How do you think I set up this circuit to get one metal to plate onto another?
Think about which side of the electrochemical cell
would I attach the metal I want to plate onto,
and the metal that I want to plate. Which side of the electric circuit
would the metal be attracted to, those positive metal ions
in the solution? Now, it's your turn. What metals do you think you could etch
or plate at home? What concentrations of electrolyte
solutions do you think would make it work better or worse?
See what you can come up with and share with us at Ontario Science Center
on Instagram. In our companion doc you'll find more
tips and strategies to help you do electric etching and electroplating.