# Standing Waves & Resonance

Item no.: F15

##### Introduction

In nature, waves could be generalized into three major types, that is, mechanical wave, electromagnetic wave and matter wave. While compare to these wave styles the existence of mechanical wave, such as the photographs of spring, metal ring and mass-spring system demonstrated, is obvious much easier to be acknowledged. Especially, the string-wavepropagation is usually held as a general teaching topic for local physical laboratory. Classify wave characteristic mentioned; how to specify the working conditions inducing the standing wave (resonant state) will become a common subject, which is also available to determine a 2-D Chladni resonance patterns on the various aspect of metal plate.

##### Objective
1. Analytic resonance of standing wave for string
3. Bohr atom model
4. Vibration modes of spring
5. Metal resonance strip
##### Experiment—String wave experiment

Consider an elastic string is tied to mechanical driver and the other side is under tension by hanging mass subjected to a string over pulley arrangement. The string is held taut by the applied force of the hanging mass. Under the length L and linear density ρ of spring are specified, the resonance occurring at appropriated vibrating frequency f and tension T will be formulated as follow, here λ indicates the corresponding wavelength.

##### 實驗項目：
1. 研究細線駐波的性質並測定振動頻率
2. 演示不同形狀金屬板克拉德尼圖形
3. 演示波爾原子共振模型
4. 演示長直彈簧的駐波
5. 演示長直金屬片的共振

##### 實驗器材：
1. 振動發生器x1
2. 桌邊定滑輪及固定架x1
3. U 型金屬砝碼架x1
4. 鋁製砝碼10g x4
5. 不同質量細繩200cm長 x3
6. 圓金屬片Φ25cm x1
7. 方型金屬片25x25cm x1
8. 扁長金屬片40x1cm x1
9. 兩段式鐵棒60cm長 x1
10. 圓環用細塑膠條或金屬條x1
11. 彈簧掛鉤 x1
12. 細長彈簧 x1
13. 細沙
14. 自備或選購品 – 正弦波發生器 x1