Brief description of the SCLPX

SCLPX is a new simple experimental system that was developed at the High School in Nový Bydžov. For its implementation you need only:

• laser pointer
• solar cell
• cable with 3.5 mm jack connector on one end
• household items: paper cardboard comb, wooden sticks, tape, modeling clay, string, etc.

As the software you can use any program to record sound, we have proved the following two freeware programs:

• Free Audio Editor - download from: http://www.free-audio-editor.com/
• Visual Analyser - download from: http://www.sillanumsoft.org/download.htm

SCLPX
Equipment of a workplace (not counting computer) is about 15 Euro (laser: 2 Euro, solar cell: 2 Euro, cabel: 4 Euro - can be divided into 2 workplaces, microphone: 3 Euro, other: about 2 Euro).

Professional sets the type of ISES, Vernier, IP Coach, Pasco, etc.
Equipment of a workplace (not counting computer) costs about cca 800 Euro - 1.600 Euro.

The prices listed above are approximate, they are calculated according to the current price list of manufacturers and they are set for 1 workstation with standard equipment. For the purchase of additional modules, the final price is still the order of several thousand higher.

Sound card
Sound card works on the principle of AD / DA converter. It can process analog signal (e.g. from microphone) and converts its to digital. Next we can work with its using some software. A microphone or line-in input of the sound card can be used as an input.

The maximum voltage at the input of the sound card: cca 1.5 V according to the type of card.
This voltage is fully sufficient for all experiments, including those such as verifying Ohm's law. If we want to work with higher voltages, the input of soundcard must be provided by voltage divider, see Adjusting sound cards for measuring voltage up to 25 V

Fotogate
It consists of a laser pointer and a solar cell (or photodiode). The solar cell with solder connection cable end connector fitted with 3.5 mm jack connector we put into the microphone input of the sound card.
The maximum voltage at the output of the solar cell (or photodiode): about 100 - 200 mV depending on the type. The voltage is so low that in principle can not damage the sound card.

Sound card can handle only AC signal. Thanks buffer capacitor of the soundcard, we can not work with DC power (without its change). So we can connect to the input of the sound card AC signal with an arbitrary waveform (sine, square, ramp, etc.).

SCLPX experiments use transient phenomenon that occurs at the output of the solar cell if the laser beam is interrupted for example by pendulum, falling comb, etc. Typical signal after passing pendulum through the laser beam can be seen in the following figure (a similar signal is obtained by passing the paper comb, mechanical oscillator, etc.):

Fig. 1 Signal at the output of the solar cell

Experiments for high schools
All experiments published on this website are tried and tested. Some experiments will require more time to prepare, but the most of them are simple way feasible.

In each section, divided into classes of classical high school, we provide an overview of the experiments that applies to that year and step by step for each experiment will be published workflow and laboratory protocol at .docx and PDF format. If any questions, please mail mentioned in Contact.

Experiments for elementary schools
Most of the experiments can be implemented in a simpler way at primary school. We first tested these experiments with class 2. C, which corresponds to age 14 to 15 years, and from our own experience we can say that the work enjoyed the students and they understood appropriately and managed to do most of the experiments.