Science Fair Projects - Measuring static electricity
Science fair projects - Measuring static electricity ..
When ever a electric charge makes a loop in space, it creates a magnetic field. From the coiled wire of an electromagnet to a single electron orbiting an atom. In some atoms, the orbits of the electrons tends to cancel out, but many atoms have "a magnetic moment." When atoms are arranged in crystal structure, theie magnetic moments (or "spins") interact.
Depending on the type of atom, the structure can be Ferromagnetic or antiferromagnetic.
In a ferromagnet, the spins tend to align with their neighbours whereas in an antiferromagnet they tend to oppose their neighbours. So in a ferromagnetic material like Iron, structures called "domains" form. Domains are small regions containing spins that all point the same way - little magnets. But in "ordinary" iron, the domains are all randomly pointed, so their magnetic effects cancel out, so most pieces of iron will not be magnetic (or at least,not very magnetic - metals are quite good at picking up magnetism from other nearby magnets).
But when there is already a magnetic field, these domains will be forced to align themselves with the field, making the iron a temporary magnet. Then the north pole of the temporary magnet will be attracted one way and the south the other, causing the iron to be attracted to the magnet. (see figure)
The Answer to Our Puzzle
Human hair will have the highest amount of static electricity
Thus, it is described as being polarized having a positive electrical charge at the oxygen end and a negative charge located between the hydrogen. When you bring the negatively charged balloon close to the stream of water, the hydrogen end is attracted towards the balloon and the oxygen end is repelled away from it. This pair of forces twists the water molecule so that the line from the negative pole to the positive pole points towards the balloon.
Now once the water has rotated, the hydrogens are slightly closer to the balloon that the oxygen (about 30 angstroms), so the attractive force on the hydrogens is slightly stronger than the repulsive force on the oxygen, so each water molecule is attracted towards the balloon. However, as this force is quite small and the water is already moving downwards quite quickly, rather than being attracted up on to the balloon like your hair was, the stream is just bent.