[To all users]

• Easy to demonstrate how transmission of sound changes as the vacuum degree is increased by using the built-in buzzer.
• Easy to demonstrate how transmission of air changes as the vacuum degree is increased by using the built-in propeller motor and streamer.

[To teachers]

• Easy to prepare because each equipment is built-in on a board.
• Versatile because of the built-in transparent tube on board that can be used as “free space” to put any “object-under-examination” like marshmallow.

[To students]

• Easy to realize, in vacuum state, how the buzzer sound changes auditorily, as well as, how the behavior of the streamer changes visually.

• Size: 100 x 100 x 108mm
• Weight: 140g
• Propeller motor, Electric buzzer, Free space (Transparent tube)
• Power source: Size AA battery (x1) (sold separately)
• Vibration insulation rubber