Electricity and Magnetism

1. Body Fat

This device measure your percentage of body fat but what is it actualy measuring?
Why do you have to enter your height?
2. Electric motor

How does this motor work without a commutator?
3. Simplest Electric motor

Can you explain how this motor works?
4. Making energy 1

This device creates a higher PD but is it making energy?
5. Making energy 2

Can this be true?
6. Levitating train

What holds the train up?
What propels the train?
What stops the train falling of the track?
5. Magnet Gun

Does the end ball fly off faster than the first ball hits the magnet?
Is momentum conserved?