水杨酸苯酯的结晶

在显微镜下实时观察晶体生长

Crystallization Intermediate (High School) 30 分钟 ~$10.00

目标

在显微镜下观察水杨酸苯酯晶体的实时生长，研究成核、晶体生长速率以及温度对晶体形貌的影响。

背景

Salol (phenyl salicylate) has a melting point of 43°C, making it perfect for observing crystallization under a microscope in real time. It can be melted on a microscope slide and watched as it crystallizes, with the crystal fronts growing visibly. Supercooling is easily demonstrated.

安全警告

  • Salol can irritate skin — wash hands after handling
  • Handle microscope slides carefully — breakage risk
  • Do not overheat salol (decomposes above 70°C)

所需PPE

goggles

材料

  • Salol (phenyl salicylate) (2 g)
    Melting point 43°C
  • Microscope slides (3)
  • Cover slips (3)

设备

Microscope (at least 40x) Hot plate or warm water bath Tweezers Timer

步骤

1

Place a small amount of salol on a microscope slide. Warm gently on the hot plate until the salol melts (43°C). Place a cover slip on top.

5 分钟 Do not overheat — decomposes above 70°C
2

Place the slide on the microscope stage. Focus at low magnification (40x). Allow to cool.

3 分钟
3

Watch for nucleation points — small bright spots where crystal growth begins.

5 分钟
4

Observe the crystal growth fronts expanding across the field of view. Time the growth rate.

5 分钟
5

Touch a cold metal object to one edge of the slide to create a temperature gradient. Observe how crystal morphology changes with cooling rate.

5 分钟
6

Draw or photograph the crystal patterns. Note the needle-like or fan-shaped morphology.

5 分钟

预期结果

Needle-like or fan-shaped crystal fronts should be visible growing across the field of view in real time. Faster cooling produces finer needles; slower cooling produces larger, more regular crystals. Supercooling may be observed (liquid persists below 43°C until nucleation occurs).

清理

Allow slides to cool completely. Scrape off salol and dispose in solid waste. Clean slides with ethanol.

详情

类别
Crystallization
难度
Intermediate (High School)
时长
30 分钟
预估费用
$10.00
步骤数
6
材料
3

更多实验

明矾晶体的培育 30 min 盐与沙的分步结晶 35 min 硫酸铜晶体的培育 30 min 糖晶体（冰糖） 25 min 苯甲酸的重结晶纯化 45 min 过饱和与瞬间结晶 35 min 铋彩虹晶体的培育 45 min

Frequently Asked Questions

What is the objective of 水杨酸苯酯的结晶?
在显微镜下观察水杨酸苯酯晶体的实时生长，研究成核、晶体生长速率以及温度对晶体形貌的影响。
How difficult is 水杨酸苯酯的结晶?
This experiment is rated as Intermediate (High School). It takes approximately 30 minutes to complete.
What safety precautions are needed for 水杨酸苯酯的结晶?
Key safety precautions include: Salol can irritate skin — wash hands after handling; Handle microscope slides carefully — breakage risk; Do not overheat salol (decomposes above 70°C).
What materials are needed for 水杨酸苯酯的结晶?
The main materials required are: Salol (phenyl salicylate), Microscope slides, Cover slips.
What results should I expect from 水杨酸苯酯的结晶?
Needle-like or fan-shaped crystal fronts should be visible growing across the field of view in real time. Faster cooling produces finer needles; slower cooling produces larger, more regular crystals. Supercooling may be observed (liquid persists below 43°C until nucleation occurs).