Dein Suchergebnis zum Thema: Model

Graphical presentation of a water molecule: The red oxygen atom is much larger than the two connected hydrogen atoms. The angle between the two hydrogen atoms is 104 degrees, the deviation from the ideal tetrahedral angle of 109.5 degrees is explained by the large amount of space required by the two free electron pairs. Information and ideas: Introduces students to the language of chemists: What is an atom? What is a chemical compound? What is a molecule?
international Water molecule Image Graphic: Presentation of a water molecule as ball model

When waves cross over from one medium to another, the speed at which the waves spread changes. Consequently, the wave normals of the incident and broken waves have different directions. With light waves, the change in the index of refraction at the boundary is the cause; with sound waves, it is the change in the density. The graphic illustrates the case when the speed of propagation becomes slower at the transition from the first to the second medium: The wave is broken at the perpendicular of the boundary surface. An explanation of this phenomenon is provided by the Huygens‘ Principle: Every point on a wave front is the starting point for a new wave, known as an “elementary wave. The enclosing end of the elementary wave creates the new wave front. Information and ideas: Refraction at boundaries also occurs with sound waves (for example, in the atmosphere at the transition from warm to cold layers of air). Relevant for teaching: Sound/acoustics: parameters Vibrations and waves
Stiftung 2018 CC BY-SA 4.0 international Refraction Image Graphic: The wave front model

The Stirling engine is particularly well suited for explaining the general principle of the heat engine as the technical implementation of a thermodynamic cyclic process. The different temperature levels needed for a cyclic process are clearly visible with the Stirling engine in the same way as the closed process cycle. A video shows a Stirling engine in operation. The construction and functioning are explained on the basis of schematic drawings. The ideal efficiency is derived from the p-V diagram and compared with the actual efficiency. Through comparison with other cyclic processes (Otto, Diesel, Clausius-Rankine) the p-V diagram of the Stirling cyclic process promotes the better understanding of other piston engines (Otto engine, diesel engine and steam engine). Finally, the use of the Stirling engine is presented, especially in connection with the use of regenerative energies. Particularly in modern solar thermal plants the Stirling engine is frequently used for the generation of electric power. Information and ideas: Why was the Stirling engine not adopted for powering vehicles?
): The Stirling engine is the simplest form of heat engine and provides an easy model

The experiment comprises four subexperiments: • What influence does it have on the temperature if the cup is closed? – Measurements in an open cup • What influence does it have on the temperature if the cup is closed? – Measurements in a closed cup • What influence does the color of the absorber have? – Measurements in a closed cup with a black absorber • What influence does the color of the absorber have? – Measurements in a closed cup with an aluminum foil absorber For each subexperiment, the students are first provided with an overview of the materials to be used and safety information. This overview is followed by the detailed, step-by-step instructions for conducting the experiment. Afterwards, the students are asked to note their observations. Specific questions are used to guide the students as they analyze the results of the experiments. At the end, the students are asked probing questions related to the experiment (an answer sheet is available for teachers). Notes: • Observe the safety information in the instructions as well as the applicable safety guidelines for your school and discuss it with your students.
students on conducting the experiment "Greenhouse effect in a drinking cup – A model

This very simple experiment can be used to teach students to readily recognize and differentiate the physical phenomena underlying the greenhouse effect, such as radiation, reflection, absorp-tion, and heat radiation. The students will need some prior knowledge to be able to interpret the results of the experiment. For this reason, the experiment can be used in two ways: Either as verification of material learned after an introduction of the topics mentioned above, or as an introduc-tion to the greenhouse effect, a hot topic in the news, with further study of the physical principles afterwards. The materials and apparatus supplied for this experiment allow eight groups of students to work simultaneously. The experiment comprises four subexperiments: • What influence does it have on the temperature if the cup is closed? – Measurements in an open cup • What influence does it have on the temperature if the cup is closed? – Measurements in a closed cup • What influence does the color of the absorber have? – Measurements in a closed cup with a black absorber • What influence does the color of the absorber have? – Measurements in a closed cup with an aluminum foil absorber Notes: • Observe the safety information in the instructions as well as the applicable safety guidelines for your school. • All materials mentioned in the instructions will have to be purchased directly from commercial sources.
information on conducting the experiment "Greenhouse effect in a drinking cup – A model

The test can be conducted in one of two ways. • Each answer is checked immediately. If the answer is incorrect, the student can repeat the question. • The answers are not checked until the end of the test. Incorrect answers can be corrected at the end of the test. When all questions have been answered correctly, students have the option of printing a personalized certificate. Information and ideas: The second test mode is particularly suitable for fast test rounds.
Language Deutsch English Español (CREA) Substance properties and particle models

Please note: There are various models on the number and division of continents.
Please note: There are various models on the number and division of continents.

The animation makes it clear that technical devices are often based on natural “models
The animation makes it clear that technical devices are often based on natural “models

Die Siemens Stiftung bietet ein eigenes Medienportal für Unterrichtsmaterialien, auf dem Lehrkräfte und andere Bildungsbeauftragte kostenfrei Lehr- und Lernmaterialien downloaden können. Die verfügbaren Medien sind pädagogisch-didaktisch geprüft, am Lehrplan ausgerichtet und sofort einsetzbar.
wertvoll sind die umfassenden Materialien zum Arbeiten mit dem Monash Simple Climate Model

This applies particularly for models with a working piston and cylinder made from
This applies particularly for models with a working piston and cylinder made from