Marktplatz für digitale Bildungsmedien
Lifting heavy loads using a rope running over a roller does not have to counteract the friction. This film explains how adding a second roller means that only half as much force has to be applied. Multiple rollers in the right sequence create a practical pulley. We look at the physical basics of these tools.
Am 26. April 1986 explodierte der vierte Reaktor des Atomkraftwerks in Tschernobyl und veränderte das weltweite Bewusstsein für die Risiken der Atomenergie. Dieses Medium verbindet Augenzeugenberichte, Erinnerungen von Michail Gorbatschow und Bilder des Fotografen Igor Kostin zu einem chronologischen Protokoll.
Es ist für Wissenschaftler nicht leicht zu beantworten, was Licht eigentlich ist. Das liegt unter anderem daran, dass es sowohl Welle als auch Teilchen ist. Licht könnte als extrem leistungsstarker Datenspeicher dienen, wenn es nicht zu schnell wäre. Forscher in Boston arbeiten daran, es zu verlangsamen.
Das Thema Elektrosmog hält sich seit langer Zeit in den Medien. Der Film erklärt, was es damit auf sich hat, und erläutert, auf welche Weise sich die naturwissenschaftliche Forschung dem Thema annähert. Die damit verbundenen Probleme werden erläutert und die aktuellen Forschungsergebnisse vorgestellt.
No other component is used as frequently in electronic devices as the transistor. This video tells the story of the component: how it was invented, how it revolutionized and drove technology, how exactly it works and what uses have been found for it over time - especially since the beginning of the digital age.
The invention of the diode was soon followed by the development of another electrode - the triode. This was the first amplifier. These amplifiers were used extensively until the transistor almost completely replaced them. As the video shows, electron tubes are now only used in high-end guitar amplifiers.
Power is a measure of the speed of work, and the watt is the unit in which energy consumption is measured. The film gives the definition of watt. You can compare mechanical, thermal and electrical power and easily convert them into each other. This video explains why and how this conversion is possible.
The moon does not shine itself, but only reflects the light of the sun. That is why the phases of the moon depend on it. The film shows how the moon changes in our perception depending on the angle it is at to the sun. At an angle of zero degrees it is new moon, at an angle of 180 degrees it is full moon.
Mass is one of the seven basic physical quantities. This video gives an understandable definition of this quantity, names its unit of measurement and explains how it is related to the force of weight. Colloquially and outside the physical context, mass is also called weight, which can lead to confusion.
This video explains the concept of a magnetic field. It clearly describes some essential effects of magnetism and illustrates the concept of field lines. The film shows what the Earth´s magnetic field is all about, it clarifies geographical and magnetic poles and goes into the phenomenon of declination.
Optical lenses are transparent, light-refracting bodies with at least one curved surface. The video introduces the different forms of lenses and how they work and shows their uses. Important terms such as focal point, refractive power and focal length are explained and the two lens formulas are derived.
Lorentz force describes the effect of magnetic fields on moving electrons. It acts perpendicularly to the magnet´s field lines and to the direction of the electrons. The film shows how to determine the direction of movement of the electrons using the three-finger rule and where this force is used for technical purposes.
Light travels at very high speed in a vacuum as well as in the air. As soon as it hits a denser material, however, its speed is slowed down. The film explains the refractive index, demonstrates why light rays are deflected in water, for example, and shows what angle is needed for a total reflection.
Levers are simple machines, or more precisely, they are mechanical force converters that magnify the force which is applied. The film explains the law of levers and shows the different forms of levers. Examples of different lever tools are given, such as scissors, tweezers, wheelbarrows, and nutcrackers.
Inertia is a physical property of all bodies. The video explains the law of inertia, according to which all bodies remain at rest or in uniform motion until an external action stops it. We encounter the law of inertia everywhere in everyday life, as the film illustrates with examples such as car and train travel.
Viele kurze Filme und Animationen bringen den Schülern das wichtige Thema Energie näher: Es wird der Unterschied zwischen fossilen und regenerativen Energieträgern ebenso erklärt wie die Umwandlung von Energie in Strom. Ihre Nutzung, zukunftsweisende Projekte und aktuelle Informationen sind weitere Themen.
Taking water as an example, the film explains the different states of aggregation of a substance. Below 0 °C, water is solid – it exists as ice. At its melting temperature of 0 °C it takes on liquid form, and at boiling temperature of 100 °C it changes to the gaseous state at normal pressure.
When light rays fall through a small hole in the front wall of an otherwise light-proof box, the image of the object that is in direct line in front of the hole is imaged overhead on the inside back of the box. The film describes step by step how this image is created and how to calculate the image size.
If the curvature of a curved mirror is convex, it distorts the mirror image. If it is concave, this is also true, except that the image is also upside down. The film explains why this is so and how the laws of reflection explain it. In addition, the video shows possible applications for everyday life.
The electrical component coil works with an interaction of electricity and magnetism. The video shows how electromagnetic induction works, i.e., the generation of electrical voltage on an electrical conductor by a changing magnetic field. The film explains inductance and Lenz´s rule and introduces the many uses of coils.
A electromagnet is made up of a coil with an iron core around which a magnetic field is generated as soon as electricity flows. This film shows how electromagnets can be used, for example as relays for high voltage circuits, for doorbells, in magnetic resonance therapy, and in particle accelerators.
Electricity flowing through a wire generates a magnetic field. If this wire is twisted into a coil, the magnetic fields of the individual turns merge into a single stronger field. An iron core in the middle can intensify this effect. With this description, the video explains the construction of an electromagnet.
The subject of this film is electromagnetic induction. A conductor loop suspended in a magnetic field illustrates how mechanical energy can be converted into electrical energy. A brief history of electromagnetic induction is given, the AC and DC voltages are explained and areas of application in industry are shown.
For a surface to reflect light, it must be very smooth. A regular reflection is given, for example, by processed glass and metal, which are used to make mirrors. The film explains the law of reflection, the creation of illusions through partial reflection, and that the mirror image is a result of our own perception.
Georg Simon Ohm discovered that voltage and current are interdependent. This video explains electrical resistance, Ohm´s law and the relationships that can be derived from it. The influence of length, strength, and temperature of a conductor as well as the calculation of electrical resistance are further topics.
The electrical resistance is defined as the quotient of the voltage and the strength of the current flowing in a circuit. At the same time, resistance also refers to a component with which a certain resistance can be realized in an electrical circuit. The film explains both terms using understandable examples.
We take it for granted in everyday life that electricity "flows". This video explains electrical circuits and the movement of electrical load carriers within them. It also looks at conductors and insulators, at the effect of negatively and positively charged materials on one another, and at induction.
In this video, the basic functional principle of the electric motor is explained. Among other things, the structure of the rotor, the stator, and the commutator in the DC motor are clearly illustrated. The film then shows the different uses of permanent magnets and electromagnets in the electric motor.
The first semiconductors were discovered in passing when people wanted to make the light bulb more economical. Since then, a lot has changed about them. The film retraces this development and explains not only how the diode works, but also some important technical terms and the use of semiconductor diodes.
This film presents four common semiconductors that we use frequently in everyday life. It explains the structure and functioning of the thyristor, the triac, the photo-semiconductor, and the LED and shows examples of where they are used - such as washing machines, elevators, light switches and headlights.