Đóng Băng Tức Thì: Nước Siêu Lạnh

Kích hoạt kết tinh tức thì của nước siêu lạnh

Classroom Demonstrations Beginner (Middle School) 120 phút ~$3,00

Mục tiêu

Minh họa hiện tượng siêu lạnh bằng cách làm lạnh nước tinh khiết dưới 0°C mà không đóng băng, sau đó kích hoạt kết tinh tức thì.

Bối cảnh

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.

Cảnh báo an toàn

  • 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

PPE cần thiết

goggles

Vật liệu

  • 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)

Thiết bị

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

Quy trình

1

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

90 phút 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 phút Handle extremely gently
3

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

2 phút
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 phút
5

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

5 phút
6

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

15 phút

Kết quả dự kiến

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.

Dọn dẹp

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

Chi tiết

Danh mục
Classroom Demonstrations
Độ khó
Beginner (Middle School)
Thời gian
120 phút
Chi phí ước tính
$3,00
Số bước
6
Vật liệu
4

Thí nghiệm khác

Chất Lỏng Phi Newton: Oobleck 20 min Cốc Thủy Tinh Biến Mất (Khớp Chiết Suất) 15 min Cột Cầu Vồng Mật Độ 30 min Kem Đánh Răng Voi 20 min Magie Cháy Trong Băng Khô 25 min Phản Ứng Dao Động Briggs-Rauscher 40 min Phản Ứng Đồng Hồ Iot 45 min Phản Ứng Natri với Nước 25 min Phản Ứng Thermit 30 min Phát Quang Hóa Học với Luminol 30 min

Frequently Asked Questions

What is the objective of Đóng Băng Tức Thì: Nước Siêu Lạnh?
Minh họa hiện tượng siêu lạnh bằng cách làm lạnh nước tinh khiết dưới 0°C mà không đóng băng, sau đó kích hoạt kết tinh tức thì.
How difficult is Đóng Băng Tức Thì: Nước Siêu Lạnh?
This experiment is rated as Beginner (Middle School). It takes approximately 120 minutes to complete.
What safety precautions are needed for Đóng Băng Tức Thì: Nước Siêu Lạnh?
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 Đóng Băng Tức Thì: Nước Siêu Lạnh?
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 Đóng Băng Tức Thì: Nước Siêu Lạnh?
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.