Ripple Tank Experiment: Measuring Wavelength, Frequency, and Speed of Water Waves

Introduction

• Aim of the lesson: Understand how to use a ripple tank to measure the wavelength, frequency, and speed of water waves.
• This experiment is a required practical and is covered in two parts. The second part will be in the next video.

Ripple Tank Setup

• Components:
  • Shallow tray of water.
  • Vibrating bar connected to a power pack, creates waves in water.
  • Lamp above the tank; white paper below the tank.
  • Light shining through water projects waves onto the paper.

Method for Measuring Waves

Measuring Wavelength

• Steps:
  1. Use a ruler placed on the paper to measure the wavelength.
  2. Freeze the image of the waves.
  3. Measure the distance between one wave and ten waves further, representing 10 wavelengths.
  4. Example: 10 wavelengths = 26 cm (0.26 meters).
  5. Divide by 10 to find one wavelength: 0.026 meters.

Measuring Frequency

• Definition: Frequency is the number of waves passing a point each second.
• Steps:
  1. Position a timer next to the paper.
  2. Count the number of waves passing a point in 10 seconds (more accurate than 1 second).
  3. Example: 24 waves in 10 seconds ⇒ Frequency = 24/10 = 2.4 Hz.

Calculating Wave Speed

• Wave Speed Formula: Speed = Frequency × Wavelength.
• Given:
  • Frequency = 2.4 Hz.
  • Wavelength = 0.026 meters.
• Calculation: Multiply to find speed: 0.0624 meters per second.

Alternative Method to Find Wave Speed

• Track a wave across the tank and measure the time it takes to travel.
• Calculate speed by dividing distance by time.
• Note: Results may vary due to measurement errors.

Additional Resources

• More questions and exercises available in the revision workbook linked in the video description.