Anderer Ressourcentyp

Siemens Stiftung

Guideline for the "Energy conversion" interactive whiteboard content

Guideline:
This document provides an overview of a possible scenario for using the content package for interactive whiteboards entitled "Energy conversion".


This guideline is intended for teachers. It presents all media of the content package and puts them in a meaningful didactic context using examples.

Anderer Ressourcentyp

Siemens Stiftung

Electrical measurements and circuits - basic course

Information sheet:
How to use a digital multimeter correctly and avoid short circuits while setting up electrical circuits.


The students will learn how to correctly use a digital multimeter (safety information, selecting the measuring range, connecting the measuring cables, etc.). In addition, circuits for simple electrical measurements are presented, and aspects to be taken into account during the respective measurements are explained. Tips are also provided for avoiding short circuits when setting up circuits and for handling batteries and accumulators competently.

Information and ideas:
The topics covered in this basic course are dealt with only to the extent and in the detail necessary for working with Experimento | 10+.

Bild

Siemens Stiftung

Muscle power

Photo:
Two people jogging.


Information and ideas:
An example of the process whereby chemical energy is converted into mechanical energy.

Bild

Siemens Stiftung

Magnetic energy

Overview graphic:
Two manifestations of magnetic energy are compared: the magnetic energy of a current-bearing coil and that of an elementary magnet.

Magnetic energy is the energy that is stored in a current-bearing coil in the form of its magnetic field. It is the result of the work that the current has to perform in opposition to the induced voltage (Faraday?s law of induction). Conversely, this magnetic energy is released again in the form of electric current when the magnetic field collapses. Magnetic energy is also stored in a magnetized material. It is equivalent to the work that must be expended in order to align the magnetic dipoles of this material in an external magnetic field. In ferromagnetic materials, the magnetic dipoles align themselves in small zones ("Weiss domains"), even without an external magnetic field. If the Weiss domains are now aligned by an external magnetic field, a permanent magnet is produced.
Incidentally: If a permanent magnet is heated above a critical temperature, it loses its magnetization. The magnetic energy is released as additional heat at this so-called Curie temperature.

Information and ideas:
A simple experiment on magnetization: If you pass a permanent magnet over an iron nail, it magnetizes the nail. What work has to be expended for this, apart from the friction work? Is the permanent magnet or its magnetic energy "used up" in the process?

Bild

Siemens Stiftung

Lightning - electrical energy from the sky

Photo:
Bolt of lightning between the Earth and clouds - an excellent example of electrical energy in nature.

Rising streams of air generate electricity from mechanical energy by means of friction in the form of electrically charged clouds, up to a charge of 20 ampere-seconds (As). If the voltage difference between the storm cloud and the Earth is greater than 100 million V, a powerful discharge will occur as an electric arc. Because the discharge takes place within fractions of a second, high currents of up to 100,000 A can occur. For example, at a charge of 20 As and a discharge time of 0.4 ms, the current is 50,000 A. At this current, the power of a lightning bolt is 5 terawatts (TW). One TW equals one billion watts. Energy totaling 560 kWh is released in the process.

Information and ideas:
For further study, the physics of the gas discharge could be discussed. Another interesting exercise is to calculate the energy content of a bolt of lightning and to compare it with the calorific value of gasoline. What amount of gasoline corresponds to the energy of a bolt of lightning? Another example of the occurrence of electrical energy in nature is the electric eel, which produces electrical energy from a biochemical reaction.

Experiment

Siemens Stiftung

A4 Evaporation heat (student instructions)

Experimentation instructions for Experimento | 10+:
Detailed instructions and questions for students on conducting the experiment "Evaporation heat - How to cool with heat". This experiment comprises two subexperiments.


The experiment comprises two subexperiments:
· Why do you freeze in wet clothing?
· How does a wet cotton pad cool you?

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.
· This student instruction is also available in Word format (doc-file).

Anderer Ressourcentyp

Siemens Stiftung

A2 Storing heat (answer sheet)

Answer sheet:
For the student experimentation instructions of the same name.

The answer sheet contains sample answers to all questions asked in the student experimentation instructions. In some cases, the answers are very short, often only in the form of key words. Depending on the learning objective, they can be augmented and enlarged upon with additional material from textbooks or Internet research.
Likewise, the answer sheet will be elaborate on the analyses for the individual subexperiments, but only in cases where experience shows that there could be difficulties.

You will find more detailed information in the related experimentation instructions "A2 Storing heat (student instructions)", which are available on the media portal of the Siemens Stiftung.

Anderer Ressourcentyp

Siemens Stiftung

A1 Electric current from solar cells (teacher instructions)

Experimentation instructions for Experimento - 10+:
Background information on the content and practical information on conducting the experiment "Electric current from solar cells - We build a dye-sensitized solar cell". This experiment comprises three subexperiments.

The experiment comprises three subexperiments:
· Building a dye-sensitized solar cell
· Power output of the dye-sensitized solar cell at different light intensities
· Higher voltages through several dye-sensitized solar cells

This experiment is particularly suitable for an introduction to solar cells, since unlike experiments with premade silicon cells, students can experience hands-on the working principle behind solar cells. With the experiments in chemistry class, students can verify their knowledge from the Bohr model of the atom (electron energy levels and excitation) and also apply their knowledge of redox chemistry. In biology class, the experiments with the dye-sensitized solar cell can best be used to introduce or illustrate the topic of photosynthesis. The experiments are not really difficult, but require attention to detail. Experienced students can easily conduct all three subexperiments in the allowed time of approx. 45 min. For inexperienced students, teachers should schedule more time or possibly skip subexperiments 2 and 3. The experiment also lends itself very well to use during a project day on renewable energy.

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.

Anderer Ressourcentyp

Siemens Stiftung

Daniell cell (reaction equation)

Interactive graphic:
The reactions and the standard potential of the galvanic cell can be shown individually.


There are two alternatives for filling in the interactive table with the partial equations and the redox reaction:
· all cells at once
· each cell individually.


Experiment

Siemens Stiftung

A4 Combining batteries (teacher instructions)

Experimentation instructions for Experimento | 8+:
Background information on the content and practical information on conducting the "Combining batteries? experiment, which comprises two subexperiments.

The teacher instructions include information on the following: the main question, relevance to the curriculum, skills, notes on conducting the subexperiments, the research group, and further research assignments.

What happens if the battery in the electric circuit is too powerful? What dangers are there if the individual components are not compatible? How can you recognize which parts can be combined in an electric circuit even before you assemble them?

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.