Lissajous Sounds

Two small mirrors vibrate at the same frequency as two loudspeakers. One mirror (and one of the loudspeakers) vibrates at a fixed frequency, the frequency of the other mirror (and the other loudspeaker) can be adjusted as desired. A green laser beam is projected onto a screen via both mirrors and creates visual oscillation images there; the corresponding acoustic counterpart of this oscillation is audible. Integer multiples of the first frequency result in beautiful stable patterns; what sounds good also looks good!

thema-Links

Acoustics

Mechanics

Physics

Vibrations and waves

dokument-Links
10260 Lissajous mit Klang DEFI

Lissajous mit Klang (10260)

Experiment-Links
Sound Bite Main

Sound Bite

Tune in to tunes with your teeth. When you listen to a radio or music player, you normally hear the sound coming from the speaker or headphones. But sound…

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11374 Haupt

"Delta Phi"

by Joachim Sauter The chrome-plated surface of the exhibit resembles a strongly moving water surface. Illuminated from above with a torch, the incoming light…

10601 1

2x2 Puzzle

Four cubes fit together in the box. Each cube has 4 quarter-pictures, one on each of 4 faces. The other two faces are transparent, BUT they look onto the…

11798 Detail II

3D-Shadows

Shadows gain depth. Illuminated with red and green light, a tetrahedron casts a red and a green shadow on the screen. Viewed through glasses with red and…

11976 Phänomen

847 Compass needles

There are 847 compass needles attached to a disc. Because they are so close together, they influence each other. With a magnet, the compass needles can be made…

10104 Detail

A Slice of Turbulence

by Ned Kahn If the crest of the wave collapsed over the surfer off Hawaii and he could bring home a slice of salami from it, he would have the original to the…

10006 Detail

Additive Color Mixing

Mixing light colors. Play with red, green, and blue light, and with their brightness. When overlapped and adjusted optimally, red, green, and blue produce…

11490 Haupt

Adhesive Air

Coandă Effect: How shape, position, and surface influence airflow. The Coandă effect occurs when fluid or gas jets deviate from their original flow direction…

10515 Haupt

Aeolian Landscape

by Ned Kahn Alongside water and ice, wind is the shaping element of the natural landscape. This exhibit allows for the pleasurable "terraforming" of gently…

10262 Haupt

Air Bubbles

A pump can be used to force air into a water-filled glass tube. However, not all air bubbles rise vertically. Some do, others choose more of a zigzag or spiral…

11634 Haupt

Air cushion

Inventive talent is called for here! Use scissors and tape to build objects out of paper that float on the wide air cushion. While testing and optimising, you…

11484 Air Fountain Haupt

Air Fountain

Dance with scarves. They rise and fall. Colorful scarves, moved by the airflow as if by an invisible hand. Choreography: visitors on the platform. by Daniel…

11478 Haupt

Air lift

The vacuum makes the difference. When the ball moves up the tube, the airflow is directed in such a way that a vacuum is created. How must it be directed for…

10581 Illustration alt

Air Mirror

Sit comfortably and check the stripy view at the end of the road. Now heat up the road. (A solid steel plate rapidly heats to 100°, warming the dark sand of…

10012 Haupt

All Triangels are the same

Using different triangular shapes, congruent shadows are to be cast on a pattern wall with equilateral triangles.

10570 Illustration alt

Anamorphic Images: Cone

On a flat surface the images are distorted beyond recognition – a peculiar visual code requiring a special key. Slip the square sheets over the reflective…

10569 Illustration alt

Anamorphic Images: Cylinder

On a flat surface, the images are distorted beyond recognition - a special visual code needs a special key. Put the square panels over the reflective cylinder:…

10398 Detail

Angled Mirrors

With two mirrors that can be brought to different angles to each other around an axis, polygons (so-called polygons) can be made in a simple way. At very…

10018 Haupt

Anti Gravity Mirror

Half a person becomes whole. Reflect the right half of the body, and there you have it: a complete person. It’s fascinating to watch them move. Can you manage…

10344 Haupt

Ascending magma

by Ned Kahn No, it is not real magma, but this model magma nevertheless makes it clear to us what processes are going on deep under a volcanic vent. Air is…

10030 Haupt

Aurora

A different kind of reflection. Colored filters in a mirror: why don’t we simply see their exact image? The surface of the mirror is rough. Restless,…

10598 1

Back View

Step forward to check how neat (or not….) your bum really looks in those cool new jeans: every clothes’ store should have this back-view booth!

10239 1

Ball in a Bowl

Anyone who has ever swung a hula hoop around their waist or a daler in a bowl knows what this is all about. Inside a large Plexiglas ball, two balls can be…

10240 Haupt

Ball in a Bowl

Which of the two balls reaches its destination faster? Of course, the one that runs the shortest distance between the start and the finish - or so you…

10035 Detail

Ball on water-beam

What makes table tennis balls stick to the water fountain? Obviously, the ball does not ride in the middle of the jet and rotates so that it comes towards the…