Show filters Hide filters

Refine your search

Publication Year
Author & Contributors
1-36 out of 267 results
Change view
  • Sort by:
26:53 IWF (Göttingen) English 1985

The Planar Double Pendulum

Computer experiments made it possible to describe the complex dynamics of this classical exemple in mechanics. To begin with, the various types of motion of the double pendulum are presented. With the help of the method of Poincaré sections, a qualitative survey of the complex dynamics follows, with special emphasis on irrational winding numbers (golden ratio).
  • Published: 1985
  • Publisher: IWF (Göttingen)
  • Language: English
26:34 IWF (Göttingen) German 1985

Das ebene Doppelpendel

Physikalisches (Realaufnahmen) und mathematisches (Computer-Simulationen) Doppelpendel; ausführliche Diskussion der Bewegungsformen (periodisch, quasi-periodisch, chaotisch) in Abhängigkeit von zahlreichen Ausgangssituationen bei verschiedenen Energieniveaus. Aufbau und Interpretation zugehöriger Poincaré-Schnitte. Darstellung des Zerfalls der "letzten KAM-Linie".
  • Published: 1985
  • Publisher: IWF (Göttingen)
  • Language: German
31:47 IWF (Göttingen) English 1992

Development of Colony and Nest in the Bumblebee (Bombus terrestris)

Documentation of the biology of the genus Bombus including seasonal social and ecological pressures. After the passage of winter the fertilized queen starts a new colony. She collects nectar and pollen and looks after the nest until the first worker pupates. The film documents the subsequent food collection and storage, oviposition, growth of the nest, feeding of the young workers and the first males, nectar flights of the drones, copulation, hibernation of the young queen and leaving the nest in autumn.
  • Published: 1992
  • Publisher: IWF (Göttingen)
  • Language: English
09:50 IWF (Göttingen) English 1993

Nest-Building Activities of the Bumblebee Bombus lapidarius

Building work in the nest is done initially by the queen but increasingly by the workers. The collection of sufficient food reserves (here nettles and poppy) is essential for the growth of the nest. The film shows the structure of the nest, the building of a nectar container, the closing of an egg gallery and building of a roof. The most important building material is wax.
  • Published: 1993
  • Publisher: IWF (Göttingen)
  • Language: English
16:48 IWF (Göttingen) English 1994

Flower-Ecological Relationships between Bumblebees and their Nectar Flow Plants

The relationships between bees and flowers are various, however the goal is the same, nutrition in return for pollination. Pollen and/or nectar is readily available in blossoms without perianthers (willow) and several blossoms with radial symmetry (gooseberry, apple, roses and many Compositae). In more complex radial symmetric blossoms (iris) and the majority of zygomorphic blossoms (clover, lupin, nettle, snapdragon, monkshood) demands are made on insects in terms of proboscis length, body weight, stamina and strength.
  • Published: 1994
  • Publisher: IWF (Göttingen)
  • Language: English
06:51 IWF (Göttingen) English 1996

Providing the Brood with Pollen Nutrition in the Bumblebee Bombus pascuorum

The meadow bee (sub genus Megabombus) is called a "pocket maker" because after visiting flowers packets of pollen collect in shoe-like "pockets" where after they are processed by the mandibles and given to the larvae. This behaviour is contrasted to that of Bombus terrestris, a "pollen storer".
  • Published: 1996
  • Publisher: IWF (Göttingen)
  • Language: English
05:26 IWF (Göttingen) German 2003

Trägheit des Magnetfeldes: Induktive Schaltverzögerung

The switching on and off of electric devices is usually characterized by their instantaneous response. The presence of inductors with large self-inductance can, however, cause considerable delays. Iron cores can lead to additional delays resulting from a change of the magnetization. Such delays, extending over minutes, will be shown here. A large copper spool is wound on a heavy closed iron core. It can be connected with a switch to a 2 volt accumulator (lead-acid battery) and a projection ammeter of short response time (less than 1 sec). The time is measured with a large, hand-operated (historic) stopwatch. These experiments always are extremely surprising, considering that we tend to associate electric phenomena with the idea of the instantaneous, the timeless.
  • Published: 2003
  • Publisher: IWF (Göttingen)
  • Language: German
01:21 IWF (Göttingen) German 2003

Bestimmung des elektrischen Erdfeldes

The electric field of the earth will be determined. A parallel plate capacitor of area 1 m2 is attached to the end of a long bamboo pole. The capacitor is connected to a ballistic galvanometer calibrated to measure current pulses (charges). On a balcony outside the lecture hall, the capacitor is held with its plates horizontal.
  • Published: 2003
  • Publisher: IWF (Göttingen)
  • Language: German
02:09 IWF (Göttingen) German 2004

Kapazität einer Kugel

Experimental determination of the capacitance of a sphere.
  • Published: 2004
  • Publisher: IWF (Göttingen)
  • Language: German
07:36 IWF (Göttingen) German 2004

Stromlinien-Modellversuche

The goal is the demonstration of two-dimensional streamline patterns as they occur when non-viscous fluids flow around obstacles. The patterns shown are models, since they have been produced in a viscous fluid under conditions of laminar flow.
  • Published: 2004
  • Publisher: IWF (Göttingen)
  • Language: German
01:59 IWF (Göttingen) German 2004

Maxwellsche Scheibe

A body that is being accelerated downward weighs less than when at rest. This is demonstrated with a flywheel on a shaft suspended on one arm of a household scale (Maxwell's disk). It is suspended on one arm of the scale with two strings which wrap around the thin shaft. When the flywheel is released, it accelerates downward, and the scale reads a reduced weight. During the subsequent rise (the flywheel still accelerating downward!) the scale again indicates a reduced weight.
  • Published: 2004
  • Publisher: IWF (Göttingen)
  • Language: German
00:54 IWF (Göttingen) German 2004

Schwanke Achse

An object rotates stably around its axis of maximum moment of inertia, even if it is attached to a bent supple shaft. The experiment also shows that particles leave a rotating object by flying off in a tangential direction.
  • Published: 2004
  • Publisher: IWF (Göttingen)
  • Language: German
01:27 IWF (Göttingen) German 2004

Elektrischer Wind

At sharp corners, even small voltages can lead to large electric fields. They can ionize the surrounding air, making it electrically conducting.
  • Published: 2004
  • Publisher: IWF (Göttingen)
  • Language: German
01:22 IWF (Göttingen) German 2003

Zirkulare Schwingungen

Through superposition of the linear oscillations of two leaf springs of almost equal frequencies, linear, elliptic and circular oscillations can be generated and shown by optical projection.
  • Published: 2003
  • Publisher: IWF (Göttingen)
  • Language: German
02:42 IWF (Göttingen) German 2004

Wirbelstrombremse

Forces are demonstrated which arise when an electric conductor moves through an inhomogeneous magnetic field.
  • Published: 2004
  • Publisher: IWF (Göttingen)
  • Language: German
00:50 IWF (Göttingen) German 2004

Kräfte im elektrischen Feld

Between two surfaces separated only by a small gap, small voltages can lead to appreciable forces.
  • Published: 2004
  • Publisher: IWF (Göttingen)
  • Language: German
01:22 IWF (Göttingen) German 2004

Seifenblasen im elektrischen Feld

The repulsive force between two bodies carrying charges of the same sign will be demonstrated.
  • Published: 2004
  • Publisher: IWF (Göttingen)
  • Language: German
03:28 IWF (Göttingen) German 2004

Magnetischer Spannungsmesser

A long induction coil wound on a flexible hose is used to explore the magnetic field near current carrying conductors and also near a permanent magnet.
  • Published: 2004
  • Publisher: IWF (Göttingen)
  • Language: German
03:10 IWF (Göttingen) German 2004

Induktion in bewegten Leitern

A conductor moving in a magnetic field experiences an electric field.
  • Published: 2004
  • Publisher: IWF (Göttingen)
  • Language: German
03:04 IWF (Göttingen) German 2004

Induktion in ruhenden Leitern

A changing magnetic field generates an electric field.
  • Published: 2004
  • Publisher: IWF (Göttingen)
  • Language: German
01:55 IWF (Göttingen) German 2004

Magnetisches Drehfeld

A rotating magnetic field results from the superposition of two magnetic fields oriented perpendicularly to each other, which vary sinusoidally with equal frequency, but with a phase difference, ideally of 90 degrees.
  • Published: 2004
  • Publisher: IWF (Göttingen)
  • Language: German
02:28 IWF (Göttingen) German 2004

Elektromagnet

It will be shown that in a small electromagnet surprisingly large forces can be generated. However, these forces decrease drastically with the introduction of only a small gap between the pole faces.
  • Published: 2004
  • Publisher: IWF (Göttingen)
  • Language: German
01:21 IWF (Göttingen) German 2004

Sphärische Aberration

The imaging error called "spherical aberration" is demonstrated by imaging a small coil of a light bulb.
  • Published: 2004
  • Publisher: IWF (Göttingen)
  • Language: German
01:03 IWF (Göttingen) German 2004

Paramagnetische Materie

Paramagnetic matter gets pulled into regions of a large magnetic field. For the demonstration, liquid oxygen is poured into a shallow container placed in front of an electromagnet with non-parallel faces.
  • Published: 2004
  • Publisher: IWF (Göttingen)
  • Language: German
01:33 IWF (Göttingen) German 2004

Induktionsläufer

Eddy currents induced in an aluminum disk in a moving inhomogeneous field tend to move the disk along with the field. This is the principle of the induction motor.
  • Published: 2004
  • Publisher: IWF (Göttingen)
  • Language: German
01:48 IWF (Göttingen) German 2004

Reflexionskegel

The reflection of light is demonstrated using a polished steel tube. The reflected light has the shape of a cone.
  • Published: 2004
  • Publisher: IWF (Göttingen)
  • Language: German
08:43 IWF (Göttingen) English 1997

Contractile Vacuoles

The activity of contractile vacuoles of amebas (Amoeba proteus), heliozoans (Actinophrys sol), flagellates (Chilomonas), ciliates (Blepharisma, Paramecium) and freshwater sponges (Ephydatia) is shown by means of cinemicrography - in some cases at extreme magnification. The complex system of contractile vacuoles found in Paramecium is illustrated by means of 3-dimensional animations.
  • Published: 1997
  • Publisher: IWF (Göttingen)
  • Language: English
08:39 IWF (Göttingen) German 1997

Kontraktile Vakuolen

Die Tätigkeit der kontraktilen Vakuolen von Amöben (Amoeba proteus), Sonnentierchen (Actinophrys sol), Geißeltierchen (Chilomonas), Wimpertierchen (Blepharisma, Paramecium) und Süßwasserschwämmen (Ephydatia) wird in mikroskopischen Aufnahmen - z. T. in extremer Vergrößerung - dargestellt. Das komplizierte kontraktile Vakuolensystem von Paramecium wird im dreidimensionalen Trick erläutert.
  • Published: 1997
  • Publisher: IWF (Göttingen)
  • Language: German
09:55 IWF (Göttingen) English 1998

Ballistospore Discharge in Basidiomycetes

Violent spore discharge in mushrooms and other basidiomycetes uses the same mechanism: Due to certain morphological and physiological properties of the spore wall, two liquid droplets are formed. When these two droplets coalesce, the surface area of the fusion droplet is reduced, which instantly generates energy utilized in spore discharge. Investigations were made with Itersonilia perplexans, a ubiquitous fungus which is easily grown in culture. The film introduces the organism, shows for the first time the process preceding spore discharge, and presents experiments which clarify the origin of the drops. The processes and physical forces during spore discharge are explained by animation. Includes time-lapse.
  • Published: 1998
  • Publisher: IWF (Göttingen)
  • Language: English
09:55 IWF (Göttingen) German 1998

Abschuß von Ballistosporen bei Basidiomyceten

Alle Ständerpilze, die ihre Sporen abschießen, folgen demselben Mechanismus: Morphologische und physiologische Eigenschaften der Sporenwand bewirken, daß zwei Flüssigkeitstropfen entstehen. Die schlagartige Veränderung der Oberflächen- und Grenzflächenenergie beim Zusammenfluß beider Tropfen wird als Impuls für den Abschuß genutzt. Itersonilia perplexans, ein leicht zu handhabender aquatischer Pilz, dient als Untersuchungsobjekt. Der Film stellt diesen Pilz vor, zeigt erstmals die Vorgänge, die dem Abschuß vorausgehen, und dokumentiert Experimente, welche die Herkunft der Tropfen klären. Ein Trick verdeutlicht die Vorgänge und physikalischen Verhältnisse beim Abschuß. Mit Zeitraffung.
  • Published: 1998
  • Publisher: IWF (Göttingen)
  • Language: German
12:25 IWF (Göttingen) English 1999

Pilobolus, a specialised coprophilous Fungus

Pilobolus, the hat thrower, is a minute fungus belonging to the Mucorales, which grows on the dung of herbivores. It has adapted itself to their way of life and ingestive habits: in the daily rhythm of its phototropic sporangiophore development, violent sporangium discharge, the attachment mechanism of its sporangia to herbage, and spore germination. The video-tape carefully documents the asexual development of the fungus by time lapse cinematography and lays emphasis on the phototropism of the sporangiophores and discharge of the sporangia.
  • Published: 1999
  • Publisher: IWF (Göttingen)
  • Language: English
08:03 IWF (Göttingen) Silent film 1976

Thalassoma bifasciatum (Labridae) - Paar- und Gruppenlaichen im Korallenriff

In the protogynous wrasse Thalassoma bifasciatum two different ways of spawning do occur: pair-spawning is performed by gaudy (terminal) males and single females whereas in group-spawning individuals with only the drab color pattern (females and younger mature males) are engaged. In both ways of spawning the movements are similar to each other: In a quick rush the sex partners raise about ½ - 1 m above the bottom towards the open water and release their sex products at the vertex of their upward movement. Thereupon they separate from each other immediately and return to the ground. The behavioral inventory in pair-spawning is enriched by a specific male behavior. The male owns a spawning-territory and marks it optically by more or less vertical looplike jumps. When a mature female approaches the male starts to circle above its sex partner until both are ready for the common spawning rush. Whereas pair-spawning can be seen in all areas that are inhabited by Thalassoma bifasciatum, group-spawning is restricted to well developed reefs with a high population density. The film demonstrates both ways of spawning and their preceding movements in the natural environment at normal speed and with slow motion pictures (64 f/s).
  • Published: 1976
  • Publisher: IWF (Göttingen)
  • Language: Silent film
12:03 IWF (Göttingen) German 1985

Präparation des Labyrinths beim Katzenhai

As a first step, the chondrocranium of the dogfish is cleaned from the skin and adhering muscles from above. By cautiously working with a scalpel, thin superficial layers of the cartilage are cut away until the holes of the three semicircular ducts are opened. The rest of the preparational proceeding is done by means of a pointed steel forceps which is used for cutting or breaking the cartilage away. In the final spots, the results of the preparation is displayed: The three semicircular ducts together with three ampullae and the utriculus in their natural spatial arrangement.
  • Published: 1985
  • Publisher: IWF (Göttingen)
  • Language: German
25:08 IWF (Göttingen) English 1997

Kovalevskaya Top

The dynamics of this third integrable case of classical rigid body theory is presented on several levels of abstraction, starting from real motion of a physical model and an analogous computer simulation of the Kovalevskaya equations of motion. The first abstraction involves the separation of a cyclic angular variable, i. e., the transition to a reduced description, and the introduction of a six-dimensional (gamma-iota)-phase with two Casimir constants. In the next step, relative equilibria are used to identify bifurcations between different topological types of three-dimensional energy surfaces. The third level is concerned with the foliation of these energy surfaces by invariant tori, and the identification of critical tori which mark bifurcations in the type of foliation. The tori are shown in various 3D projections and in homeomorphic deformations of the energy surfaces. The final step in the analysis uses the technique of Poincaré surfaces of section. A comprehensive survey on all possible motions is given in terms of animation series where all Poincaré sections for a given energy are shown in succession.
  • Published: 1997
  • Publisher: IWF (Göttingen)
  • Language: English
00:48 IWF (Göttingen) German 2004

Perspektive

Two-dimensional images of three-dimensional structures have a perspective, that is a certain ratio of size and distance for things which lie behind each other. The perspective depends on the position of the centers of the projection, which in imaging lie in the centers of the entrance- and exit-pupils. Using the images of two objects positioned at different distances from the imaging lens, the perspective and its changes will be shown.
  • Published: 2004
  • Publisher: IWF (Göttingen)
  • Language: German
01:45 IWF (Göttingen) German 2004

Chromatische Aberration

Chromatic aberration occurs in imaging as result of the wavelength dependence of the index of refraction. It will be demonstrated on a special example.
  • Published: 2004
  • Publisher: IWF (Göttingen)
  • Language: German
out of 8 pages
Loading...
Feedback

Timings

  100 ms - page object
   44 ms - search
    0 ms - highlighting
    0 ms - highlighting/10895
    0 ms - highlighting/10430
    0 ms - highlighting/10869
    0 ms - highlighting/10898
    0 ms - highlighting/10879
    0 ms - highlighting/10892
    0 ms - highlighting/10894
    0 ms - highlighting/14318
    0 ms - highlighting/17107
    0 ms - highlighting/10896
    0 ms - highlighting/10368
    0 ms - highlighting/10370
    0 ms - highlighting/10880
    0 ms - highlighting/10374
    0 ms - highlighting/17106
    0 ms - highlighting/14902
    0 ms - highlighting/14904
    0 ms - highlighting/10873
    0 ms - highlighting/14317
    0 ms - highlighting/10893
    0 ms - highlighting/10877
    0 ms - highlighting/10867
    0 ms - highlighting/10901
    0 ms - highlighting/10868
    0 ms - highlighting/10872
    0 ms - highlighting/10383
    0 ms - highlighting/10875
    0 ms - highlighting/10881
    0 ms - highlighting/10361
    0 ms - highlighting/10900
    0 ms - highlighting/10882
    0 ms - highlighting/10874
    0 ms - highlighting/10878
    0 ms - highlighting/10876
    0 ms - highlighting/17105
    0 ms - highlighting/17104

Version

AV-Portal 3.8.0 (dec2fe8b0ce2e718d55d6f23ab68f0b2424a1f3f)