Sound need medium for propagation . take a speaker and kept it in a totaly closed glass box from all side on the speaker what you observe the sound cannot be heard outside the glass box.

Introduction:

Sound is a form of energy that is created when an object vibrates, causing the surrounding air particles to vibrate as well. These vibrations then travel through the air as waves, which we perceive as sound. However, sound cannot travel through a vacuum or empty space; it requires a medium for its propagation. This can be demonstrated through a simple science experiment.

Materials needed:
- A bell or any other object that can produce sound
- A vacuum chamber or a glass jar with a lid
- A vacuum pump (if using a vacuum chamber)
- A speaker or microphone connected to an oscilloscope (optional)

Procedure:
1. Set up the vacuum chamber or glass jar with a lid on a table.
2. Place the bell or object that produces sound inside the chamber or jar.
3. Close the chamber or jar tightly to create an airtight seal.
4. If using a vacuum chamber, connect the vacuum pump to the chamber and remove the air from inside until a vacuum is created. If using a glass jar, simply close the lid tightly.
5. Once the vacuum is created, try ringing the bell or producing sound from the object inside the chamber or jar.
6. Observe and listen for any sound.

Observation:
When the bell is rung or sound is produced inside the vacuum chamber or glass jar, no sound will be heard.

Explanation:
The absence of sound in the vacuum chamber or glass jar demonstrates that sound requires a medium for its propagation. In this experiment, the medium for sound propagation is air. When the vacuum is created inside the chamber or jar, the air is removed, creating a vacuum or empty space. Without the presence of air particles to vibrate and transmit the sound waves, the sound cannot travel, resulting in silence.

Additional points:
- This experiment can be further enhanced by connecting a speaker or microphone to an oscilloscope. The oscilloscope will display the sound waves produced by the bell or object, providing a visual representation of sound propagation.
- This experiment can also be performed using other mediums, such as water or a gas, to demonstrate that sound propagates differently in different mediums.
- It is important to ensure that the vacuum chamber or glass jar is airtight to prevent any leakage of air during the experiment, which could affect the results.