Sound Propagation Demonstrator (Teaching instrumnet)

• Condition: Used
• Customized: Customized
• Certification: ISO9001
• Type: Educational Equipment
• Transport Package: Carton Box
• Specification: As shown in the figure
• Model NO.: 2225
• Trademark: SHUN MA / OEM
• Origin: Yuyao Zhejiang China
• HS Code: 9023000000
• Production Capacity: 50, 000PCS/ Month

Product Description

Product Description

Sound Propagation Demonstrator (Teaching instrumnet )

Product Introduction
The product consists of a panel, a sealable container (including a sounder and receiver), a solid sound bar, a loudspeaker, a power indicator, a volume adjusting device, a terminal, a connecting hose, a foot, a funnel, a water stop clip, etc.
Two piezoelectric ceramic pieces are installed in the sound propagation cylinder. The upper signal storage generator sends out an electrical signal with a frequency of about 500Hz to drive it to send out a continuous drink sound. When the sound propagation cylinder is filled with air, liquid or a sound transmitting rod is put in, the lower piezoelectric ceramic chip generates an audio signal after receiving the audio sound, which is amplified to send out a continuous audio sound from the loudspeaker. If the air in the sound propagation cylinder is removed with a dual-purpose air cylinder, the audio sound from the loudspeaker will immediately be significantly reduced. Theoretically, if a complete vacuum is pumped, the following piezoelectric ceramic chip will not receive audio sound, and the speaker should not emit audio sound. But in fact, because it is impossible to completely pump the vacuum, and part of the sound is transmitted to the piezoelectric ceramic plate below through the sound propagation cylinder wall, the speaker still emits a slight audio sound. V2triode and T1 transformer form a transformer coupling oscillator to generate an oscillation frequency signal of about 500Hz, which is connected to a piezoelectric ceramic chip B1 on the sound propagation cylinder through a connecting wire to generate a continuous audio sound. Because the piezoelectric ceramic chip has a low sound generation efficiency, the audio sound is low.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  
Product Specification

Product name	Sound propagation demonstrator
Material	Plastic(ABS)
Structure	The product consists of a panel, a sealable container (including a sounder and receiver), a solid sound bar, a loudspeaker, a power indicator, a volume adjusting device, a terminal, a connecting hose, a foot, a funnel, a water stop clip, etc.
Power supply	DC6V
Panel size	240×340×25mm

Instructions
1. Preparations
Take the instrument out of the storage box, put two No. 7 batteries into the signal generation box, and put four No. 5 batteries into the amplifying speaker box. Turn on the power switch, the indicator lights of both boxes should be on, and then turn off the power switch. Put the amplifying loudspeaker box on one side of the demonstration board, and insert the two banana plugs of the connecting line into the lower terminal of the acoustic microphone. Unscrew the screw cap on the microphone, take out the generator base, and insert the two banana plugs of the connecting wire of the signal generator box into the terminal.

2. Verify that the sound can be transmitted in the air
Sound can be transmitted through air for language communication and music appreciation, which does not need to be verified. However, in order to verify that sound cannot be transmitted in vacuum for comparison, this experiment is conducted first. Turn on the power switch of the signal generator box, the indicator light will light up, and the sound pedestal will emit a light sound with a frequency of about 500Hz, so that students can listen to it. Put the sound base on the upper end of the voice transmitter, turn on the power switch of the amplified speaker box, and the indicator light will light up, and you can hear the same continuous sound of about 500Hz from the speaker as the sound base. If you turn off the power switch of the signal generator box, the sounder will not make any sound, and the sound of the loudspeaker will disappear. Turn on the power switch, and the loudspeaker will sound, indicating that the sound is transmitted through the air in the sound propagation cylinder.
During the experiment, please note that when the sound base is not installed on the upper end of the sound propagation cylinder, do not turn on the power switch of the amplifying loudspeaker box, otherwise a self-excited whistle will be generated.

3. Verify that the sound cannot be transmitted in vacuum
Connect the air extraction port of the dual-use air cylinder to the rubber tube at the lower end of the transmission cylinder, clamp the upper air inlet rubber tube with a clamp, and check the tightness between the sounder and the transmission cylinder. When the dual-use air cylinder is used for air extraction, the 500Hz continuous audio sound emitted from the amplified loudspeaker box will be significantly reduced, indicating that with the increase of the vacuum in the pipe, the sound transmission capacity will decline until only a very small sound can be heard. This is because it is impossible to pump the transmission cylinder to a complete vacuum.

4. Verify that sound can propagate in solids
Remove the air intake hose on the sound generator, and the air will enter the sound transmission cylinder. Turn off the power switch of the signal generation box and the amplifying loudspeaker box, remove the sound base, put the sound transmitting rod into the sound transmitting cylinder, and make sure that the upper and lower ends are in contact with the piezoelectric ceramic sheet. Then turn on the signal generation box and the power switch of the amplified loudspeaker, and the loudspeaker will emit a loud 500Hz continuous audio sound, indicating that the plastic rod, a solid, can transmit sound.

5. Verify that sound can be transmitted in liquid
Turn off the power switch of the signal generation box and the amplifying loudspeaker box, take down the sound base, take out the sound bar, and then put the sound base in place. A small funnel is sleeved into the skin tube at the lower end of the sound propagation cylinder. The funnel is raised to be higher than the sound propagation cylinder, and water is injected through the small funnel (a few red ink can also be added to increase the observation effect). Until the water is immersed in the piezoelectric ceramic sheet on the sound generator, turn on the power switch of the signal generation box and the amplification speaker box, and the loudspeaker will emit a loud 500Hz audio sound, indicating that the sound can be transmitted through the liquid.

6. End of work
Turn off the power switch of the signal generation box and the amplified loudspeaker box. Drain the clear water in the sound propagation cylinder and dry it in the air. If it does not work for a long time, take out the batteries in the signal generation box and the amplification speaker box, and put the instrument into the storage box as required.

Product feature and application
The sound propagation demonstrator can demonstrate sound propagation in different media such as air, liquid and solid, but not in vacuum. The instrument puts the sound generator and the sound receiver into a sound propagation cylinder. By changing the state of the medium in the cylinder, it demonstrates in a hierarchical way that the sound propagation effect is different in different media. Use a dual-use air cylinder to remove the air in the cylinder. Although the sounder continues to make sound, the sound received by the sounder is significantly reduced. If complete vacuum can be pumped, the sound receiver will not receive sound, indicating that sound cannot be transmitted in vacuum state. This instrument is mainly used for classroom demonstration experiment and student experiment of physics in secondary and higher schools.

Maintenance and precautions
1. During the sound propagation demonstrator experiment, turn on the power switch of the signal generation box first, and pay attention to turn on the power switch of the amplified loudspeaker box after the sounder is installed on the sound propagation cylinder. At the end of the experiment, turn off the power switch of the amplified loudspeaker box first, and then turn off the power switch of the signal generation box to prevent the amplified loudspeaker box from generating a self-excited whistle.
2. After the instrument is used, especially after the experiment of liquid transmitting sound, it must be wiped and dried before it can be put into the storage box for storage. If the instrument is not used for a long time, take out the dry battery to prevent the instrument from being damaged by leakage.
3. Before the experiment, carefully check whether the upper and lower tubes are connected tightly. If there is air leakage, the effect of vacuum experiment will be affected.
4. The instrument shall be handled with care and shall not be collided or dropped. After use, it shall be stored on a cool, dry and ventilated instrument rack and covered with a dust cover.
5. After the instrument is used for a long time, the rubber seal ring will age. If the sound transmission cylinder leaks, replace the rubber seal ring.
6. The circuits of the signal generation box and the amplified loudspeaker box are relatively simple. In case of failure, check against the electrical schematic diagram and replace the damaged components.

Detailed Photos