Soap bubble demo

Purpose: Explain thin film interference.

Parts:

  • C.V Boys cup
  • Screen
  • 200 W Lamp w/ power supply
  • Little water
  • Dish soap and the wiper to lay the soap film on the cup
  • Camera and tripod to take a video out
  • computer to display the output

 

Set up:

schematic of the setup
schematic of the setup

Set up the demo as in the instructions on the card, pictured above. The actual setup is shown in the  photograph below.

Actual Setup
Actual Setup

Notes:

Keep the Boy cup as shown in the picture below(little tilted) so that excess water will drain down making a very thin film in the top part of the cup.

thumb_dscn1693_1024

Set a camera to the film, so that a clear video of it can be taken to a computer.

thumb_dscn1722_1024

Wet the rim of the cup, Take some soap solution to the glass wiper and wipe it through the rim of the cup so that it will make a thin film of soap through the rim.

Watch the video out from the computer.