Sound is a form of energy in Sound – Class 9 Science Experiment
Chapter Name: Sound
Activity Name: Sound is a form of energy in Sound
Activity Description:

In this experiment, we will demonstrate how sound is a form of energy by using a tin can and a laser light. The tin can is turned into a hollow cylinder by removing both ends, and a balloon is stretched over one end.
A rubber band is wrapped around the balloon, and a small piece of mirror is stuck onto the balloon. A laser light is directed at the mirror so that the light spot is reflected onto a wall. When we shout directly into the open end of the can, we will observe the light spot on the wall “dancing.”
Required Items:
- Tin can
- Balloon
- Rubber band
- Small piece of mirror
- Laser light
- Wall to observe the light spot
Step by Step Procedure:
- Take a tin can and remove both ends to create a hollow cylinder.
- Stretch the balloon over one end of the can.
- Wrap a rubber band around the balloon to hold it in place.
- Attach a small piece of mirror onto the balloon’s surface.
- Set up the laser light to shine onto the mirror’s surface, so the light spot is reflected onto the wall.
- Without making any sound, observe the position of the light spot on the wall as a reference.
Experiment Observations:
- With no sound, the light spot remains stationary on the wall.
- When shouting directly into the open end of the can, the light spot on the wall starts to “dance” or vibrate.
Precautions:
- Be careful when handling the laser light to avoid direct exposure to eyes.
- Do not shout too loudly or too close to the laser setup to prevent any damage or accidents.
- Make sure the mirror is securely attached to the balloon to avoid it falling off during the experiment.
Lesson Learnt from Experiment:
The experiment demonstrates that sound is a form of mechanical energy. When we shout into the open end of the tin can, the sound energy causes vibrations in the can’s walls, including the stretched balloon.
These vibrations are transferred to the mirror attached to the balloon, causing it to vibrate as well. As a result, the light spot on the wall appears to “dance” due to the reflection of the vibrating mirror. This shows that sound energy can produce mechanical effects, making it a form of mechanical energy.