"Test showing the behaviour of iron filings placed above magnets with alternating polarities...N,S,N,S etc."
from http://www.youtube.com/watch?v=qG5JnpXbLkY
Alternating Polarity (N/S/N/S) Iron Filings Test (YouTube)
"Test showing the behaviour of iron filings placed above magnets with alternating polarities...N,S,N,S etc."
from http://www.youtube.com/watch?v=qG5JnpXbLkY