消失的烧杯（折射率匹配）

将玻璃物体浸入折射率匹配的液体中使其隐形

Classroom Demonstrations Beginner (Middle School) 15 分钟 ~$8.00

目标

通过将玻璃物体放入折射率匹配的液体中使其消失，演示折射率的概念。

背景

We see transparent objects like glass because light bends (refracts) at the surface where the glass meets air. The degree of bending depends on the difference in refractive index between the two media. If a glass object is placed in a liquid with the same refractive index, light passes through without bending, and the object becomes effectively invisible. Pyrex glass (n ≈ 1.474) nearly matches vegetable oil (n ≈ 1.47), creating a stunning visual effect.

安全警告

  • Vegetable oil is slippery — clean up spills immediately to prevent falls
  • Glass objects can break — handle with care

所需PPE

goggles

材料

  • Vegetable oil (or glycerol) (500 mL)
    Refractive index ≈ 1.47
  • Pyrex glass beaker or rod (1)
    To disappear
  • Regular glass rod (1)
    For comparison (different n)

设备

Large glass beaker (1 L) or clear container

步骤

1

Fill the large beaker about 2/3 full with vegetable oil.

2 分钟
2

Show the Pyrex glass object to the audience. Note that it is clearly visible in air.

1 分钟
3

Slowly lower the Pyrex glass into the vegetable oil. As it submerges, it gradually becomes invisible.

3 分钟 Lower gently to avoid splashing
4

For comparison, lower the regular glass rod into the same oil. It remains visible because its refractive index does not match.

3 分钟
5

Discuss: light refracts at boundaries between materials with different refractive indices. When n values match, no refraction occurs and the object seems to disappear.

6 分钟

预期结果

The Pyrex glass becomes nearly invisible when submerged in vegetable oil. Only slight distortions at the edges may be visible. The regular glass rod remains clearly visible in the same oil.

清理

Remove glass objects and wash with dish soap. Oil can be saved for reuse or disposed of in general waste. Wipe up any oil spills.

详情

类别
Classroom Demonstrations
难度
Beginner (Middle School)
时长
15 分钟
预估费用
$8.00
步骤数
5
材料
3

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Frequently Asked Questions

What is the objective of 消失的烧杯（折射率匹配）?
通过将玻璃物体放入折射率匹配的液体中使其消失，演示折射率的概念。
How difficult is 消失的烧杯（折射率匹配）?
This experiment is rated as Beginner (Middle School). It takes approximately 15 minutes to complete.
What safety precautions are needed for 消失的烧杯（折射率匹配）?
Key safety precautions include: Vegetable oil is slippery — clean up spills immediately to prevent falls; Glass objects can break — handle with care.
What materials are needed for 消失的烧杯（折射率匹配）?
The main materials required are: Vegetable oil (or glycerol), Pyrex glass beaker or rod, Regular glass rod.
What results should I expect from 消失的烧杯（折射率匹配）?
The Pyrex glass becomes nearly invisible when submerged in vegetable oil. Only slight distortions at the edges may be visible. The regular glass rod remains clearly visible in the same oil.