Have you ever heard of the Philosopher's Stone?

No, not this one.

But this one?

The idea of a Philosopher's Stone dates back to the time of alchemy, that is from the 1st

to the 3rd century after Christ.

At that time, people wanted to synthesize the Philosopher's Stone in order to transform

base metals into silver or gold.

But this wish will probably remain a wish forever, because without silver or gold salts,

no metals can be created.

To demonstrate this to you, we have recreated a process in the laboratory that you might

also be familiar with, or at least its application.

Yes, that's right.

This is a Christmas tree ball, and its gloss is achieved with the silver mirror or tolerance

test.

Let's see how it works exactly.

First of all, a silver salt, in our case it is a silver nitrate salt, is put into a small

glass.

Next, ammonia is added until no more silver precipitate is visible.

This sounds strange at first, since we actually want to produce silver.

But for now, we just want to convert the silver salt into another complex.

Now sodium hydroxide is added in the form of platelets.

This will adjust the pH of the solution.

However, the dissolution of the platelet can take some time.

Then the sugar solution is added.

Ordinary dextrose can also be used for this.

The aldehyde groups in the sugar give off electrons, which the silver ion in the solution

takes up and precipitates as metal.

This is called a redox reaction.

The silver now precipitates on the wall of the glass.

And voila, we have silver plated the glass from the inside.

This procedure can of course be repeated on larger glass bottles.

Here we have mirrored colored glass bottles.

You can see the effect which is also shown by the Christmas tree balls.

By coloring the bottles, our silver no longer looks silver at all, but only acts as a mirror.

But today we will show you that gold and silver can also be colored on their own.

Silver and gold can not only be deposited on large surfaces, but also remain in solution

as small particles.

These particles can have a size of a few nanometers and are therefore only visible under an electron

microscope.

For example, depending on the size and shape of the particles, their solution can take

on different shades of color.

You can even make these small metal particles with things from everyday life, such as a

lemon and of course a silver or gold salt.

The juice of the lemon contains vitamin C, also called ascorbic acid and citric acid.

Both are components that are needed for the production of the particles, on the one hand

as stabilizer of the particles and on the other hand as a reducing agent.

Unfortunately the content of acid in a lemon is quite low, so the reaction will take longer

than usual.

But first the pulp must be separated from the juice as well as possible and for this

purpose the juice is centrifuged.