Bei der dritten Lautrer Solar Power Competition belegen gleich zwei Teams aus Winnweiler die ersten beiden Plätze.

Wie kann die Energieversorgung in der Zukunft gesichert werden? Nach der Ära von Kernkraft, Kohle und Co. müssen sich die Industrienationen und jene auf dem Weg dorthin überlegen, welche Alternativen zur Verfügung stehen. Vor diesem Hintergrund veranstaltete die Hochschule Kaiserslautern ihren jährlichen Wettbewerb LSPC zum Thema Energiespeicherung. Speziell ging es um die Möglichkeiten lastenangepasster Stromversorgung.

Vor der Anmeldung erhielten die Bewerbergruppen die Rahmenbedingungen der Aufgabe und mussten einen Entwurf einreichen. Direkte methodische Vorgaben zur Umsetzung gab es nicht. Entscheidend war lediglich, dass eine von der Hochschule zur Verfügung gestellte Menge Energie möglichst effizient gespeichert und an ein zu bewegendes Objekt weitergegeben wurde. Ausgestattet mit einem eigenen Budget machten sich die Teams von verschiedenen weiterführenden Schulen in Rheinland-Pfalz ans Werk und konstruierte einen eigenen Energiespeicher.

Das WEG war mit zwei Teams im Rennen. Beide wählten die Verwendung von Hochleistungskondensatoren zur Speicherung der Energie und zur Bewegung der betroffenen Masse. Diese löteten sie selbst zusammen und überzeugten in der Kategorie Leistung mit hervorragenden Resultaten. Zum Lohn gab es die ersten beiden Plätze in dieser Sparte.

Der Leiter des Projekts, Physiklehrer Dr. Harry Fuchs, war mächtig stolz auf seine Schüler. Er und das gesamte Team freuen sich nun darauf, das Preisgeld zur Durchführung weiterer spannender Projekte am WEG zu verwenden.

Formel M*-Wettbewerb am WEG
(* Autos mit Mausefallen-Antrieb)

Schülerinnen und Schüler kämpfen um den Sieg. Das Sieger-Auto von Erik und Svenja Baumgärtner (Physik-Grundkurs 11) schafft satte
8,60 m – und ist Sieger im diesjährigen Wettbewerb der Mausefallen-Autos. Zwar wurde der aktuelle Weltrekord mit 140 m nicht eingestellt – aber es machte allen viel Spaß. Auch eine Menge an technischem knoff-hoff wurde in die Konstruktionen eingebaut … physics – physics…….


Das Sieger-Duo

Das Siegerauto

Bar Code - Reader : Handscanner
school level
general theme
special theme
approx. 1 week
1 hour
10 min
Boys and girls produce a bar code-reader, and measure the electrical currents in dependence of the black or white pattern of a bar code.

  • phototransistor BPY 62-3 or other
  • bulb with lens 3.7 V
  • 1.5 V battery
  • 9 V battery
  • ammeter 100 mA
  • block of wood or plastic (approx. 70 mm x 25 mm x 25 mm)
  • black and white pattern
    EAN-barcode (Fig. 1)
  • wires
  • soldering iron
  • ruler and pencil
  • black paper
  • adhesive tape
  • drilling machine
  • grimlets 4 mm, 6 mm, 10 mm
Reasonable prized electronic parts can be  solved at mail-order business. Wooden and plastic parts can be bought at home  improvement stores. The teacher might already arrange for blocks to be sawed  according to the above  specifications.

1. Production of the reading head
A block of wood or plastic has to be sawed according to the above measurements, if not already prepared. Then, holes are drilled into the block with a drilling machine, as shown in Fig. 2 (measurements in mm).

If the opening at the bottom where both drillings converge is wider than 5 mm, black paper and adhesive tape may be used to tape it to a narrow slot (improvement of resdution). Then, two electric cirduits are produced, using a soldering iron and wires (Fig. 3).
After that the photo-transistor is placed in the 6 mm wide opening, and the bulb in the 10 mm wide opening. Additionally, a marking has to be put on the front side of the block, opposite to the slot at the botton.

2. Production of the bar code
You can copy the above EAN-code into DIN-A4 size, oblong format (best in black and white). Put a mm-scale closely below the bar code, beginning at the left edge of the sheet.

3. Reading of the bar code
Put the scanner on the top of the bar code, move it over the sheet in steps of 1 mm using the marking and thje scale, and read the respective currents.

The result is a transformation of the black and white pattern into a peaked curve of the currents in relation to the distance (measured values range between 10 mA and 40 mA). If the narrowest maximum is assigned to the value 0 and the narrowest minimum to 1, the result is a chain of 1 and 0 : digital information.

Instead of measuring the signal with an ammeter and drawing the measured values into a diagram, an x-y-writer can also be used in order to obtain the curve relating currents to distance. The soldering iron can be replaced by paper-clips and adhesive tape.

Methodical Advice
The extent of the teacher‘s preparations may vary according to the students‘ abilities. The making of the wood / plastic block may also be carried out at the same time in acts and crafts.
Coding and digitizing might be topics of interest in computer science and mathematics.
Electric Toothbrush
school level
general theme
special theme
aprox. 1 hour
5 min
An electric toothbrush helps to demonstrate the principle of the contactless charging of a rechargeable cell and the solid state operation of an electric motor, respectively.

  • electric toothbrush
  • power supply 10V~/5A~
  • 5 wires (30 – 50 cm long)
  • inductor coils, fitting into each other
  • low voltage d.c. motor
  • diode (e.g. 1N4007)
  • oscilloscope (optional)
  • an iron core for the coils

In order to clarify the relationship between the original and the model, make sure to take the toothbrush apart so that you can show its relevant elements and their functions (fig.1 and 2).
The power supply of the toothbrush also serves as its electric charger. After opening the case you can see a small transfomer, which is applied to a printed circuit board, and the coil, which is soldered to the printed circuit board. You needn´t pay too much attention to the other components, resistors etc. which are not really necessary for the understanding of the phenomenon..
The opening of the toothbrush itself might cause some difficulty as it is watertight when closed.In this case, you can either use a saw or a knife for cutting the toothbrush open along its welded joint carefully. After that you can pull it apart.
If you wish to avoid possible slipping, it is advisable to clamp the toothbrush in a vice.
Now you can see a small coil which is connected with a rechargeable cell by a diode and a wire. The electric motor in the upper part of the toothbrush can possibly be used for the further model
It is most likely that the rechargeable cells of defective toothbrushes are leaking. If so, avoid any kind of contact.

Experiment / Function
Before starting to set up the model, make sure to place the components on the table in a manner that allows the pupils to understand their combination in the model later.
Connect the primary coil with the power supply. Connect the scondary coil with the core with the electric motor by help of a diode. Now push the secondary coil with the core into the primary coil, and the motor will start running because of electromagnetic induction (fig.3 and 4).
On an oscilloscope you can make the d.c. current visible which is necessary for the charging of a rechargeable cell. At this point, the rectifier-function of a diode could also be explained.
The coils are getting warm after some time, which, however, is completely harmless, considering the shortness of the experiment. Yet, you might make use of this effect and let the pupils estimate the efficiency factor of the apparatus.

It also makes sense to let the pupils estimate the life of an electic toothbrush with a rechargeable cell. Considering that one charging provides 20 minutes of usage and that the cell can be charged a thousand times, you can clearly see that after 333 hours the toothbrush cannot be used any more. Until then you will have brushed your teeth 6666 times, if you brush them twice a day for three minutes each time, as recommended. The toothbrush will be nine years old then.
Without difficulty, results like these can be transferred to other machines with rechargeable cells, like razors or cordless phones.

Methodical Use
This experiment helps to explain electromagnetic induction as well as, especially, the principle of the transformer. Apart from that, the function of the diode can also be explained.

Micromechanical Airbag Sensors as Motion Sensors

(paper in german: Stetzenbach, Eckert, Jodl, Blauth, Thomas: Praxis der Naturwissenschaften Heft 2, 2003 (14-17)

Best performances in sports have always thrilled young people.

The first step towards excellence is, of course, the organization of training units. But that is – by far - not enough. Skill and experience of trainers are no longer sufficient to optimise technique and performance with their trainees. Today notebooks and digital cameras are fundamental tools in a high-tech equipment. First class swimmers, for instance, optimise their training by acceleration sensors, normally used in modern cars to perceive crash situations, to make the airbags work or to prevent cars from skidding and turning over in extreme situations of driving. With the swimmers they register all relevant acceleration processes such as racing dive, pushing off, transitions from pushing off into gliding and swimming action. The possibility of the direct registration of acceleration can be turned into a personal experience within the instructional process and leads to a practical understanding and dealing with this central term of Mechanics. In the past, instruction in Physics had to take a deviation towards acceleration via the measuring of distance and time. Today generous sponsors provide schools with adequate sensors. Following the instructions you can use them without any problem. For registration a school Interface is sufficient. Detailed information about the construction and function of the acceleration sensor can be provided by the producer.


For our experiments we have used an acceleration sensor BOSCH SMB 060. This tool can register acceleration in x- and y- direction. For the better understanding of its construction and function we look at a sensor SMB 050 which only provides a signal in x-direction.




The process of acceleration causes a steering of the Seismic Mass attached to Springs. Mobile electrodes are connected with the Seismic Mass. They are installed as Capacitors and opposed to fixed counter-electrodes. There is only a tiny gap between the counter-parts. Moving the mobile electrodes brings about changes within the Capacitors C 1 and C 2. A capacitance-voltage-transfer turns the change into a measurable voltage that is proportional to the acceleration a .

The general function can easily be understood by 11 formers.

Exp.: If you change the distance between the electrodes of a capacitor, you measure a current.





Airbag – Sensor: Analysis of Movement


school level

general theme

special theme

theoretical level

practical level





16 - 20





inelastic collision







ca. 15 min

ca. 10 min


Typical human movement patterns can be registered with the help of commercial airbag sensors.





  • Airbag-Sensor (Bosch SMB 50 Best.-Nr 0 273 101 143)

  • Interface Cobra , Cassy o.ä. (auch Speicheroszilloskop geeignet)
  • Meßsoftware

  • PC

  • BNC-Verbindungskabel



  • SMD-Europlatine (Elektronik-Versandhandel)

  • 2 BNC-Einbaubuchsen

  • Festspannungsregler 7805

  • Diode 1N4148

  • 2 Kondensatoren 0,1 mF

  • Widerstand 10 kW

  • Ein-/Ausschalter

  • 9 V Batterie-Block

  • Baterrieclip für 9V-Block

  • Gehäuse mit Batteriefach



First the airbag sensor and necessary parts must be present. A SMD Euro-Circuit-Board is needed to build up the electronic device fast. The construction of a special circuit board is more complicated.


Fig. 1: wiring scheme


Fig. 2: circuit board pinning




Calibration is achieved by the free fall of the sensor. In picture 3 the sensor case is tied to a thread. The thread is burnt out to exclude disturbances. Picture 4 shows the voltage-time diagram. The precise reading registers 55 mV for the present acceleration of 1 g ( = 9,81 m/s2). Readings during the experiment: before the free fall, free fall, crash ...)




Fig. 3: Calibration


Fig. 4: Meßdaten während der Versuchsdurchführung (vor dem Start, freier Fall, Aufschlag, ...)



Experiment / Result

A test person holds tight the sensor case with his/her arm bent. The dynamic push forward of the first (picture 5) brings about the measurement diagram in picture 6: the acceleration of about 4 g is completely stopped after a time of 180 ms.


Fig. 5: Versuchsablauf and measurement diagram

The experiment is convincing because acceleration processes can be made visible easily and you gain precise information about the power acting.


- Comparisons of acceleration readings of students of different gender, ages and physical conditions.

- Analysis of motions, for example running on the spot. Comparison right leg – left leg, registration of a handicap caused by an injury or walking-problem.

Hint: to exclude disturbances the sensor must be fixed with a special tape.

- Muffling caused by shoes.

- Elasticity of a football ( while bouncing, while being shot, during a dribbling).

- Fisting off a thrown ball ( So „ A goal-keeper’s fear of a penalty shot“ becomes reality).

- Acceleration processes with tennis rackets, examination of various rackets referring to muffling.


For further activities it would be great to contact a College for Physical Education and ask for more information.

The interdisciplinary work between Physical Education and Physics brings about special motivation


A sensor can also be used to gain results easily with typical acceleration processes which traditionally cause lots of problems taking measurement deviation via distance-time diagrams; for instance:

- Recording of vibration processes by fixing a sensor to a spring.

- Recording of the vibrations of a tuning-fork, the tuning-fork can directly be put on the sensor, an oscilloscope can be used for presentation- instead of a PC.

- Analysis of acceleration processes of a loudspeaker diaphragm, caution: acceleration very high, up to 35 g!!

Bild der Wissenschaft Heft1 2002, S. 90-93

Robert Bosch GmbH, Geschäftsbereich Kraftfahrzeugausrüstung 8, Postfach 30 02 40, D-70442 Stuttgart. Fax: 0711-811 2841

Entwurf: Peter stetzenbach, Meisterschule für Handwerker, elektromechaniker-Abteilung, Am Turnerheim 1, D-67657 Kaiserslautern, tel. 06301/3647423

Suggestion by B. Freytag: Keinen Augenblick ohne Physik, in: Praxis der Naturwissenschaften-Physik 46 (1997), Heft 7, S. 43-45

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