순간 냉동: 과냉각수

과냉각수의 순간 결정화 유발하기

Classroom Demonstrations Beginner (Middle School) 120 분 ~$3.00

목표

정제된 물을 얼지 않고 0°C 이하로 냉각하여 과냉각을 실증한 다음 순간 결정화를 유발한다.

배경

Pure water can be cooled below its freezing point (0°C) without solidifying if there are no nucleation sites for ice crystals to form. This metastable state, called supercooling, can persist down to about −40°C for very pure water. When a supercooled sample is disturbed (tapped, shaken, or a small ice crystal is added), crystallization cascades through the entire sample in seconds, creating a dramatic visual effect.

안전 경고

  • Handle glass thermometers with care
  • Do not use glass bottles — they may shatter if water freezes and expands
  • Supercooled water will freeze instantly if disturbed — handle very gently

필수 개인 보호 장비

goggles

재료

  • Purified water (distilled or deionized) (500 mL)
    Must be very pure
  • Clean plastic bottles (5)
    New, unopened, smooth interior
  • Small ice crystal (1)
    Nucleation seed
  • Thermometer (−20 to 10°C) (1)

장비

Freezer (set to −8 to −10°C) Bowl Timer

실험 절차

1

Place 5 sealed bottles of purified water in the freezer, undisturbed. Set a timer for 90 minutes (adjust based on freezer temperature).

90 분 Do not disturb the bottles
2

Very carefully remove one bottle. If it is still liquid and the temperature reads below 0°C, it is supercooled.

5 분 Handle extremely gently
3

Method 1 (Impact nucleation): Sharply tap the bottle on a table. Watch ice crystals propagate through the liquid.

2 분
4

Method 2 (Seed crystal): Carefully open a second supercooled bottle and drop a small ice chip in. Watch instant freezing from the crystal seed.

3 분
5

Method 3 (Pour): Slowly pour supercooled water onto an ice cube in a bowl. Watch an ice tower build up.

5 분
6

Discuss nucleation, supercooling, and phase transitions. Explain why purity and smooth container walls are essential.

15 분

예상 결과

The water remains liquid below 0°C until disturbed. Upon nucleation, ice crystals propagate visibly through the bottle in 2–5 seconds. Pouring onto an ice cube creates a growing column of ice.

정리

Thaw any frozen bottles. No chemical waste. Return thermometer to storage.

세부 정보

카테고리
Classroom Demonstrations
난이도
Beginner (Middle School)
소요 시간
120 분
예상 비용
$3.00
단계
6
재료
4

더 많은 실험

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Frequently Asked Questions

What is the objective of 순간 냉동: 과냉각수?
정제된 물을 얼지 않고 0°C 이하로 냉각하여 과냉각을 실증한 다음 순간 결정화를 유발한다.
How difficult is 순간 냉동: 과냉각수?
This experiment is rated as Beginner (Middle School). It takes approximately 120 minutes to complete.
What safety precautions are needed for 순간 냉동: 과냉각수?
Key safety precautions include: Handle glass thermometers with care; Do not use glass bottles — they may shatter if water freezes and expands; Supercooled water will freeze instantly if disturbed — handle very gently.
What materials are needed for 순간 냉동: 과냉각수?
The main materials required are: Purified water (distilled or deionized), Clean plastic bottles, Small ice crystal, Thermometer (−20 to 10°C).
What results should I expect from 순간 냉동: 과냉각수?
The water remains liquid below 0°C until disturbed. Upon nucleation, ice crystals propagate visibly through the bottle in 2–5 seconds. Pouring onto an ice cube creates a growing column of ice.