1. A magnetic compass is one of the most fascinating gadgets children have enjoyed. I can vaguely recall how fascinated I was with the compass that used to be inside my SHOES when I was a child. I haven't seen anything like that around in the usual shops and think it might be a good marketing strategy?
Anyway to come to making a magnetic compass. Before you do so you must first understand how and why a compass works. As you may be aware the compass is behaving in this way only because something is making them behave this way. Yes the Earth's magnetic field. Although not very large it can still affect small compasses and some even believe it can affect human beings. That's one of the reasons why many people don't sleep with their heads on the North.
Rather than go into details about all this without any illustration, I thought I'd recommend you to a URL that would help you find all your answers about the magnetic compass with the help of diagrams.
http://www.howstuffworks.com/compass.htm
2. Magnets would attract three common magnetic materials such as iron, cobalt and nickel and some other not very common magnetic substances such as gadolinium, dysprosium and so on. Physicists would call these substances FERROMAGNETIC (iron-like) substances in their lingo. There are two other categories of 'magnetic substances' as well called paramagnetic (weakly-magnetic) and diamagnetic (non-magnetic) which we'll not go into detail here.
Magnets do not attract substances such as copper and aluminium. Nevertheless they can induce currents in copper and aluminium currents called EDDY CURRENTS when they move past them. These can be an advantage or a nuisance.
I thought a VERY GOOD link to understand this better would be to read an answer given by Erin Cram, a student of Molecular and Cellular Biology at the University of CA, Berkeley to a question similar to yours 'Magnets attract some objects, but not others, Why' in the URL below:
http://www.madsci.org/posts/archives/mar98/891386132.Sh.r.html
3. Yes indeed, you do create an electromagnetic field by coiling copper wire around an iron nail and then connecting the wire to a cell. An electromagnet is simply a device that is activated by passing CURRENT through a wire. The SPACE around the could where a magnetic force and hence field can be experienced is called an electromagnetic field.
Just to keep you busy browsing for a while I’m suggesting a few links for you. Happy browsing.
i). Press the button for the electromagnetic fleld demonstration.
http://www.nscdiscovery.org/FortDiscovery/CommunicationsGallery/ElectromagneticFields.htm
ii). For how electromagnets work
http://www.howstuffworks.com/electromagnet.htm
4. Any high school physics text book of Grade 10 must have the circuit diagram (except CBSE!) because it is part of their curriculum.
The basic components in an electric bell are a power supply, an electromagnet, push switch, gong with hammer, contact screw, soft iron armature and a springy metal strip.
When you push the switch to complete the circuit, the electomagnet gets magnetized and attracts the soft iron (armature) which causes the hammer to strike the gong and make the characteristic noise. However, when the soft iron is attracted it breaks the circuit and the electromagnet is no longer magnetized. This causes the soft iron to return to its original place to complete the screw. This cycle repeats to produce the characteristic ringing sound.
In any case I'm suggesing a URL to link you to Electromagnets as used in an Electric Bell. You have to scroll down to see the illustration of the bell.
http://sfiden.ednet.ns.ca/SFIden/SWAP/Elect/4ElectMag.html
5. There are numerous websites where you can find information on how to build an electromagnetic motor. The principle of the motor as you may be aware is the MAGNETIC FORCE acting ON a CURRENT carrying conductor.
Here is a sampler of URL's for your reference.
http://www.howstuffworks.com/motor.htm
http://www.bbc.co.uk/scotland/revision/physics/electricity/movement_from_electricity_rev.shtml#3
http://fly.hiwaay.net/~palmer/motor.html
6. You should find all the technical information you're looking for about the bullet train which has been running for almost four decades now in the URL below:
http://www.cs.arizona.edu/japan/www/atip/public/atip.reports.94/train.94.html