Pulling "Erhu" on the iron film, I saw the two -dimensional voice ｜ Play seriously

"The Great Works", but playing seriously

experiment equipment

The marked cup, rosin, erhu bow, iron plate, wood, hot melting glue, sand

experiment procedure

First of all, we fix the iron plate on the wood with the hot melting glue

Keep it stable and avoid drastic shaking

Then, sprinkle the sand evenly on the iron plate

Use the bow to rub on the rosin a few times

Possess the rosin on the bow and increase the friction

We rub the bows in one/2 of the iron plate side wall and rub in one direction in one direction

Make it make the same frequency sound

Then we can find that sand begins to move regularly

Gradually form such a pattern

Change the position of the bow

Write 1/4 on the side wall

The pattern has also changed

Write at the position near the top angle

Will become another form

Can change the frequency

Form different patterns

You can try it

How many of the following patterns can you make?

Picture source: bing

Original understanding

The above is the famous Kraney experiment, let's understand its principles.

The sound is generated by vibration and spreads in the form of waves. When the waves encounter obstacles during the transmission process, they will be reflected. When these two directions are encountered in the opposite direction, they will be superimposed. The red point in the figure is the lobby, and the largest position between the two adjacent sections is the wave belly.

Therefore, when the sound waves are transmitted, the sand at the rocket will remain unmoved, and the sand on the abdomen will move to the rocket to form a Craney graphic. The picture below shows the diagram of the resident wave on the metal plane.

Reference article: chladni pattern are really awesome. (Gif Series.) | Life Science blog

Edit: lychee

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