Letter 34066

Growing crystals on copper wire immersed in silver nitrate [Utah] 

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Hi,

I am the mother of a student in the 5th grade who wants to do this science experiment she saw in a book, for her science fair. The book shows a "tree" fashioned out of copper wire. emmersed in a silver nitrate in water solution. The water turns a pretty blue and crystals form on the "branches" of the copper made tree and when done, looks like a blue pine tree. All the book states is about the tranference of ions, a chemical reaction, and lists water, silver nitrate, and the copper wire in a glass beaker as needed materials. no formula or amounts of silver nitrate or water. I just recently purchased 25 grams of silver nitrate but have not opened the box as we dont want to mess with it unless we find out a proper and safe solution to perform this experiment. The science fair is at the end of Feb 05. My daughter and I would appreciate any information and help you can give us.

Thank you so much for your time. Mrs. Huju

Tammy H.
- Ogden, UT., USA

I am trying to help my son with the same.

Chris Barboza
- Houston, Texas, USA

I found this on the web since I found a large bottle of silver nitrate and I've got plenty of copper wire. Since 25g isn't a lot, you might end up with w long, skinny tree in a test tube. Just make many branches.
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Silver nitrate vs copper wire (Silver Christmas Tree)
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Materials:
copper wire 16ga best, 18ga a bit light
silver nitrate 0.1M, 4 liters per demo
4L beaker

Procedure:
Fashion a simple Christmas tree using the copper wire, so that it fits
in a 4L beaker
Place the "Christmas tree" into the 4L beaker
Pour the silver nitrate solution near to the brim, at least to cover the tree.

Reaction starts immediately with blackened surface. Within about an hour,
visible silver metal crystals will form on the surface of the wire, and the
previously colorless solution will become increasingly blue.

The photo shown is of a reaction of a few days -- overcooked.

Disposal - UCB procedure, no copper compounds in any quantity may be
drain disposed. Forward to disposal personnel. The silver metal must also
be disposed by disposal personnel.

Here is some safety data on silver nitrate. It sounds a good deal more harmful than it is.
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Chemical Safety Data: Silver nitrate
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Hazard: harmful Hazard: oxidizing
Common synonyms: Silver (I) nitrate
Formula: AgNO3
Physical properties
Form: colourless crystals, or white crystalline powder
Stability: Stable
Melting point: 212 C
Specific gravity: 4.33
Water solubility: dissolves to give a colourless solution

Principal hazards
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1) Poisonous if swallowed or inhaled
2) Skin contact with silver nitrate solid or solutions is likely to leave silver stains on the skin. These develop slowly over a period of hours and are initially brown, but darken gradually to black. Once the stains become apparent, they cannot usually be removed with soap and water, but gradually disappear as new skin grows.
3) Inorganic nitrates are oxidizers and may react vigorously with reducing agents.

Safe handling
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Wear safety glasses. Do not breathe dust. Do not allow solution or solid to come into contact with the skin.

Emergency
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Eye contact: Immediately flush the eye with plenty of water. Continue for at least ten minutes and call for medical help.
Skin contact: Wash off with soap and water. Remove any contaminated clothing.
If swallowed: Call for immediate medical help.

Disposal
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Small amounts of dilute silver nitrate solution can be flushed down a sink with a large quantity of water, unless local rules prohibit this. Note that silver salts are expensive, and silver may be reclaimed in your laboratory.

Protective equipment
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Wear safety glasses. Rubber, neoprene or nitrile gloves may be helpful in preventing silver stains on the skin.

Further information
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Silver nitrate
Chemicals in the HSci database
More extensive safety data

Link to the Oxford HSci web site
Oxford, ++++

Jenn Flannery
- Toronto, On, Canada

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