Download Teaching Electricity and Electronics at secondary school

Teaching electricity and electronics at secondary school
Jaromír Kekule, Charles University in Prague, Faculty of Mathematics and Physics,
Czech Republic
Abstract
This paper presents the web materials, which can help students for better
understanding and easier studying Electricity and Electronics and their use in the regular
lessons at secondary school in the Czech Republic.
Introduction
In the world the modern methods of teaching using computer are developed rapidly in
the whole world. I think that physics is especially convenient for teaching with computer
because it covers both statical and dynamical processes and things are tightly connected to
each other.
But in our country there are not many multimedia materials for use on secondary
schools. There are not many households connected to Internet and that’s why students cannot
study at home on-line. There are some problems with Internet at schools, too. But the situation
is improving.
Nowadays I am working on development an electronic textbook for teaching
secondary-school students on theme electricity and magnetism with an emphasis on
electronics and this school year I am testing this textbook experimentally in regular teaching
and learning on a secondary school.
Creation of electronic materials
My web will contain practically all of materials that are necessary for students and
teacher for teaching and learning electricity and magnetism. This theme covers whole third
form of standard secondary school.
The web is divided into 22 “chapters” The most of them are motivated by some
semiconductor parts that are interesting but not usually contained in standard textbooks for
secondary schools. The compulsory subject matter is given in fact as an explanation to it. The
greatest emphasis is put on analysis and explanation of devices, which contain semiconductor
parts.
The materials in “chapters” are well arranged and most of them have a uniform
structure. For example to every semiconductor part there is inscribed an independent page.
The first thing on this page is motivation (what is this part good for). Further there is a very
brief paragraph with description of the part, then its schematic symbol and text and picture
explanation how it works. There is a typical simple electric circuit with the part and detailed
information about its practical use with links to pages with practical devices. Experiments that
student can make by himself are included in corresponding pages and linked from an
independent list of experiments.
On the theme of common electricity and magnetism, a special emphasis is put on
explanation of function of electrical devices of everyday use and technical devices and on
analysis and explanation of some interesting electromagnetic phenomena that we can see in
nature (for example a lightning). The Book of problems of electricity and electronics is
included.
The web contains a lot of links to web pages of manufacturers of semiconductor parts
and to further relevant pages with explanation of some phenomena and devices.
Every teaching material even the expertly good and detailed one is not very attractive
when it is not well arranged. For an extensive web there is very important to have a good
navigation in the document. I think that frames are very good for it. The screen is divided into
three windows. In the largest one you can see what you want to study. The content of all the
web is in the left window and on the upper side there is a content of actual chapter. Besides,
hyperlinks are coloured (every colour has specific meaning) and contain a mark for recognize
if the hyperlink has been already visited or no. Student can go through the web in the same
way as at school (blue hyperlinks), he can go back in the past or forward to the future (green
hyperlinks), see and make experiments (brown ones). The material contains hyperlinks to the
pages on the Internet with information about great physicists.
Methods of explanation
For better student’s understanding I use various methods of explanation. The
fundament is text complemented by a lot of pictures and photographs. I make an effort that
students can comprehend some theme only with help of pictures. Where some dynamic
processes are delt a with, there are used Java applets or video. Videos are used for student’s
own work, too. Students can test their knowledge by a lot of solved problems, self-tests and
homework.
Thematical plan
And how will the classes look like? At the beginning of school year I motivated
students with some interesting problems of electricity and magnetism and especially of
electronics, for example the following topics:
- power stations – heat, water, wind or nuclear energy, problem of storage of electric
energy
- electromotor – different types
- safety devices on railways – automatic control of traffic, rail circuits, remote control;
city public transport – preference of trams on crossroads.
Now the students must learn a few fundamental topics. They must have some
fundamental knowledge about electric charge and forces existing among charges (Coulomb’s
law). Electrostatic induction and polarization are then related to electrostatic forces. The next
fundaments are electric field and its intensity, electric work, potential and voltage and electric
current (DC and AC). For comprehension, how semiconductors conduct electric current,
students must have basic knowledge about crystal structure, Pauli’s principle and energy gaps
in materials.
Next chapters are in fact explanation of some real devices or problems. Each of them
starts with some device, mostly electronic device. (By the way, almost all of modern electric
devices are electronic devices.) Students should learn what they need for explaining its
function. Then we can discuss about related topics. A list of some topics is below; behind the
hyphen there are related topics that students should learn simultaneously.
 thermometers and exposure meters – thermistor and photoresistor; resistivity of
conductors and semiconductors, dependence of resistance on temperature, light, electric field
and pressure; superconductivity
 rectifier – semiconductor of type N and P, diode, rectifying of high frequencies;
capacity and capacitor, Zener diode
 how to make high voltage – multiplier of voltage, acceleration of electrons in
picture tube; principle of oscilloscope and TV set; magnetic field, Laplace force, magnetic
induction, Lorentz force; electromagnet, electromotor, ampermeter, voltmeter
 regenerative diode – electromagnetic induction, Faraday’s and Lenz’s law, selfinduction

how to make light – bulb, conduction in gas, fluorescent lamp

amplifying of current – transistor, phototransistor, diac, FET

integrated circuits – operation amplifier, logic circuits; calculator, computer

regulation of power – resistance regulation, thyristor regulation
 radio and TV – electromagnetic oscillator, resonance, AC circuits with R, L, C,
impedance, electromagnetic waves (reflection, refraction, interference, polarization); radio
receiver, tuning (varicap), modulation and demodulation, microphone and loudspeaker

mobile phone, GPS
 how to make electric voltage and current – cell, accumulator battery, electromotive
voltage, Ohm’s law; photodiode, Hall’s phenomenon, alternator, power station, transformer,
three-phase voltage

electric power – power, energy and work in AC and DC circuits; asynchronous
motor
 how to save information – cassette, floppy disc, hard disc – materials in magnetic
field; CD, DVD
Use of the web
This year I use my in regular teaching on a secondary school.
Directly in lessons I want to use pictures and applets, which are for understanding
better than words. Students can study at home with the web. For this reason this web is
located on the Internet, on school intranet and on student’s home computers. I want to
motivate students for making on-line homework. Of course, we will make experiments and
laboratory work at school, for example with system ISES (Intelligent School Experimental
System, see http://www.ises.info/; it’s a system that can change your computer in
oscilloscope, ampermeter, voltmeter, thermometer and many other measure devices), and I
want to motivate students for making simple experiments and devices at home (See Fig. 1).
Figure 1. A simple electronic device (time switch) – inspiration for student’s own work
Conclusion
The hypertext material has a great advantage. It can be arranged in more ways, for
example by sequence of lessons or similar to paper books. The web can be used offline, too,
but for homework and links it will be necessary to have connection to Internet. Every student
has this possibility at school. All of students have a computer at home and therefore they can
study with offline version. I believe that students will accept this method and their learning
will be more pleasant and successful than so far.
.