EARTH IS VERY BIG MAGNET; BUT WHY IT DOES NOT ATTRACT IRON?
In each point of the earth, magnetic power would be 0.5 gas. (10,000gas=1 tesla) that is the magnetic power of a small CT.Scan. Its magnetic power is more than 20,000 times of the magnetic power of earth. Thus, the entire magnetic power of the earth is very high. But its power in each point is very less. Even then, the magnetic power of the earth remains on the iron. But the measure of the magnetic power is very less. So, only if the magnetic needle is so as to turn sides, it would remain towards north. If the magnetic needle is somewhat tight, it would not turn towards north.