Culture de Cristaux d'Alun

Création de grands cristaux transparents d'alun

Crystallization Beginner (Middle School) 30 min ~$6,00

Objectif

Cultiver de grands cristaux octaédriques transparents d'alun de potassium à partir d'une solution sursaturée.

Contexte

Potassium alum (KAl(SO₄)₂·12H₂O) crystallizes in a beautiful octahedral habit. It is non-toxic, inexpensive, and easy to grow into large crystals. The octahedral shape reflects the cubic crystal system of alum.

Avertissements de sécurité

  • Use care with hot water
  • Alum is generally safe but avoid ingestion of large amounts

EPI requis

goggles

Matériaux

  • Potassium alum (100 g)
    Food-grade available
  • Distilled water (300 mL)
    Hot
  • Thread or monofilament (30 cm)

Équipement

500 mL beaker Hot plate Stirring rod Pencil Filter paper

Procédure

1

Heat 300 mL of distilled water to near boiling. Slowly dissolve as much alum as possible (about 80-100 g) while stirring.

10 min Handle hot liquids carefully
2

Filter the hot solution to remove any undissolved particles.

3 min
3

Pour a small amount into a dish and let it cool to form seed crystals overnight.

2 min
4

Select the best octahedral seed crystal. Tie it to thread and suspend in the main solution.

5 min
5

Cover loosely and store in a stable, cool location. Check daily.

2 min
6

After 1-2 weeks, remove the crystal, dry with a paper towel, and photograph the octahedral faces.

5 min

Résultats attendus

Large, transparent, octahedral crystals up to 2-4 cm across after 1-2 weeks. The faces should be smooth and the crystal should be nearly colorless and transparent.

Nettoyage

Alum solution can be saved for future crystal growing or disposed down the drain. Rinse beaker.

Détails

Catégorie
Crystallization
Difficulté
Beginner (Middle School)
Durée
30 min
Coût estimé
$6,00
Étapes
6
Matériaux
3

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Frequently Asked Questions

What is the objective of Culture de Cristaux d'Alun?
Cultiver de grands cristaux octaédriques transparents d'alun de potassium à partir d'une solution sursaturée.
How difficult is Culture de Cristaux d'Alun?
This experiment is rated as Beginner (Middle School). It takes approximately 30 minutes to complete.
What safety precautions are needed for Culture de Cristaux d'Alun?
Key safety precautions include: Use care with hot water; Alum is generally safe but avoid ingestion of large amounts.
What materials are needed for Culture de Cristaux d'Alun?
The main materials required are: Potassium alum, Distilled water, Thread or monofilament.
What results should I expect from Culture de Cristaux d'Alun?
Large, transparent, octahedral crystals up to 2-4 cm across after 1-2 weeks. The faces should be smooth and the crystal should be nearly colorless and transparent.