Silver Nitrate Christmas Tree

Branching silver crystals are grown on a copper “tree” by immersing the copper in a dilute silver nitrate solution. A single-displacement redox reaction plates metallic silver onto the copper while the solution turns blue from copper(II) ions.

1. Form a small “tree” from bare copper: spiral copper wire around a cone, or twist thin wires onto a thicker trunk and fan out the ends as branches. Ensure the copper is uncoated; lightly abrade with fine sandpaper or clean with warm vinegar–salt, rinse, and dry.
2. Prepare about 0.1 M silver nitrate solution (for example, 1.7 g AgNO3 per 100 mL deionized water) in a clear glass beaker or jar.
3. Place the copper tree in the solution so it is fully submerged and not touching the container walls; avoid jarring the setup once immersed.
4. Observe as silver crystals begin to appear on the copper within minutes; leave undisturbed for 1–24 hours to grow larger dendrites.
5. Optional surface prep for difficult copper: if the wire has a lacquer coating, remove it by gentle abrasion. Only trained adults should use dilute hydrochloric acid to strip coatings; thoroughly rinse before use.

How to Make a Silver Nitrate Christmas Tree - Midnight Science Club:

Redox Reaction: Holiday ChemisTree! Copper + Silver Nitrate (Holiday Chemistry) - MrLundScience:

📄 Silver Crystal Tree Chemistry Demonstration - Science Notes: https://sciencenotes.org/silver-crystal-tree-chemistry-demonstration/

• Use different copper forms (flat sheet cut into a tree, fine copper mesh, single straight wire) and compare crystal branching under a magnifier.
• Vary silver nitrate concentration (0.05–0.2 M) to see effects on crystal size and density.
• Start several trees and remove them at different times to create a time series of dendrite development.
• Compare to a classic “copper tree”: place an iron nail in copper(II) sulfate solution to grow a copper coating by a similar displacement process.

• Wear gloves, and a lab coat; silver nitrate stains skin and fabric and can irritate eyes and skin.
• Do not ingest chemicals; keep food and drink out of the lab area. Wash hands after the activity.
• Handle glassware carefully and secure the setup to prevent spills; silver crystals are fragile and can break off.
• Collect all solutions, rinses, and silver-bearing solids as heavy-metal waste. Do not pour silver nitrate or copper nitrate solutions down the drain; follow local hazardous-waste disposal rules.

• What is the balanced reaction for silver deposition on copper, and which species is oxidized/reduced? (2 Ag⁺ + Cu → Cu²⁺ + 2 Ag; copper is oxidized, silver ions are reduced.)
• Why does the solution turn blue during growth? (Formation of copper(II) ions, which impart a blue color as Cu²⁺ complexes form.)
• Why do silver crystals form fern-like dendrites instead of smooth layers? (Diffusion-limited growth: silver atoms add fastest at tips where ion flux is highest.)
• How would changing the silver nitrate concentration or temperature affect crystal size and branching? (Higher concentration/warmer temps generally increase nucleation and can produce denser, finer branches; lower concentration/cooler temps favor slower, larger features.)
• Why must the copper be clean and uncoated? (Oxide or lacquer inhibits electron transfer and prevents silver ions from contacting bare metal to start the displacement reaction.)