Zuckerkristall-Kandis

Züchtung essbarer Zuckerkristalle an einem Faden

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

Ziel

Große Zucker-(Saccharose-)Kristalle an einem Faden züchten, um Kandis herzustellen und dabei Übersättigung und Keimbildung anhand eines essbaren Produkts zu demonstrieren.

Hintergrund

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.

Sicherheitswarnungen

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

Erforderliche PSA

goggles

Materialien

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

Ausrüstung

Saucepan Stove or hot plate Tall glass jar Pencil Clothespin

Durchführung

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.

Erwartete Ergebnisse

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.

Aufräumen

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

Details

Kategorie
Crystallization
Schwierigkeit
Beginner (Middle School)
Dauer
25 Min.
Geschätzte Kosten
$4,00
Schritte
6
Materialien
5

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Fraktionierte Kristallisation von Salz und Sand 35 min Kristallisation von Salol (Phenylsalicylat) 30 min Übersättigung und spontane Kristallisation 35 min Umkristallisation von Benzoesäure 45 min Züchtung von Alaun-Kristallen 30 min Züchtung von Bismut-Regenbogenkristallen 45 min Züchtung von Kupfersulfat-Kristallen 30 min

Frequently Asked Questions

What is the objective of Zuckerkristall-Kandis?
Große Zucker-(Saccharose-)Kristalle an einem Faden züchten, um Kandis herzustellen und dabei Übersättigung und Keimbildung anhand eines essbaren Produkts zu demonstrieren.
How difficult is Zuckerkristall-Kandis?
This experiment is rated as Beginner (Middle School). It takes approximately 25 minutes to complete.
What safety precautions are needed for Zuckerkristall-Kandis?
Key safety precautions include: Sugar syrup is extremely hot — burns risk; Supervise children during the boiling step.
What materials are needed for Zuckerkristall-Kandis?
The main materials required are: Granulated sugar, Water, Cotton string, Food coloring, Flavoring extract.
What results should I expect from Zuckerkristall-Kandis?
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.