Sucre Cristallisé (Candy de Roche)

Culture de cristaux de sucre comestibles sur un bâtonnet

Crystallization Beginner (Middle School) 25 min ~$4,00

Objectif

Cultiver de grands cristaux de sucre (saccharose) sur un bâtonnet pour créer des sucreries cristallisées, démontrant la sursaturation et la nucléation avec un produit comestible.

Contexte

Rock candy is made by suspending a string in a supersaturated sugar solution and waiting for crystals to grow. Sugar is unusual in that it is extremely soluble in water (about 2 kg per liter at 100°C) and forms large monoclinic crystals with well-defined facets.

Avertissements de sécurité

  • Sugar syrup is extremely hot — burns risk
  • Supervise children during the boiling step

EPI requis

goggles

Matériaux

  • Granulated sugar (500 g)
    White sugar
  • Water (200 mL)
  • Cotton string (30 cm)
    Unbleached
  • Food coloring (5 drops)
    Optional
  • Flavoring extract (1 tsp)
    Optional

Équipement

Saucepan Stove or hot plate Tall glass jar Pencil Clothespin

Procédure

1

Heat 200 mL water to boiling in the saucepan. Gradually dissolve 400-500 g sugar, stirring continuously.

10 min Hot syrup — burns risk
2

Remove from heat. Add food coloring and flavoring if desired.

2 min
3

Wet the cotton string with water and roll in granulated sugar to create nucleation sites. Let dry for a few hours.

3 min
4

Pour the cooled (but still warm) sugar solution into the glass jar.

2 min
5

Suspend the prepared string from a pencil across the top of the jar so it hangs in the solution without touching the sides or bottom.

3 min
6

Cover loosely and place in a stable location. Check daily for 5-7 days. Crystals should grow along the string.

5 min

Résultats attendus

After 5-7 days, large sugar crystals (1-3 cm) should form along the string, creating rock candy. Crystals are monoclinic with flat, angled faces. The result is edible.

Nettoyage

Excess sugar solution can be reheated and reused. Wash all equipment with warm water.

Détails

Catégorie
Crystallization
Difficulté
Beginner (Middle School)
Durée
25 min
Coût estimé
$4,00
Étapes
6
Matériaux
5

Plus d'expériences

Cristallisation du Salol (Salicylate de Phényle) 30 min Cristallisation Fractionnée du Sel et du Sable 35 min Culture de Cristaux d'Alun 30 min Culture de Cristaux de Bismuth Arc-en-ciel 45 min Culture de Cristaux de Sulfate de Cuivre 30 min Recristallisation de l'Acide Benzoïque 45 min Sursaturation et Cristallisation Instantanée 35 min

Frequently Asked Questions

What is the objective of Sucre Cristallisé (Candy de Roche)?
Cultiver de grands cristaux de sucre (saccharose) sur un bâtonnet pour créer des sucreries cristallisées, démontrant la sursaturation et la nucléation avec un produit comestible.
How difficult is Sucre Cristallisé (Candy de Roche)?
This experiment is rated as Beginner (Middle School). It takes approximately 25 minutes to complete.
What safety precautions are needed for Sucre Cristallisé (Candy de Roche)?
Key safety precautions include: Sugar syrup is extremely hot — burns risk; Supervise children during the boiling step.
What materials are needed for Sucre Cristallisé (Candy de Roche)?
The main materials required are: Granulated sugar, Water, Cotton string, Food coloring, Flavoring extract.
What results should I expect from Sucre Cristallisé (Candy de Roche)?
After 5-7 days, large sugar crystals (1-3 cm) should form along the string, creating rock candy. Crystals are monoclinic with flat, angled faces. The result is edible.