Final answer:
A bar magnet's magnetic field is much smaller than Earth's. Strong bar magnets can reach up to 2 T, while Earth's field is about 0.00005 T at the surface. The intensity of a magnet's field decreases quickly with distance, unlike Earth's, which encompasses the entire planet.
Step-by-step explanation:
The size of a bar magnet's magnetic field is significantly smaller than that of Earth's.
While both the Earth and a bar magnet have a north pole and a south pole, the strength of the magnetic field greatly differs. The strongest permanent bar magnets can produce magnetic fields up to 2 tesla (T), and superconducting electromagnets may exceed even 10 T. In contrast, the Earth's magnetic field measures approximately 0.00005 T (or 0.5 G) on its surface. Since the intensity of a magnetic field decreases with distance from the source (following an inverse square law similar to that of electric fields), it is evident that a bar magnet's field decreases rapidly as one moves away from it. This behavior is consistent with common experiences with magnets, where their effect is only felt within a relatively close range.
An everyday example, such as the use of a compass, further illustrates this concept. A compass points in the direction of a magnetic field, and when used on Earth, it aligns with Earth's magnetic field. However, when brought near a bar magnet, the compass will realign to point towards the magnet's poles, indicating the magnet's stronger local field as compared to Earth's at that specific location.