Final answer:
Magnetic separation is used to separate ferromagnetic materials like paper clips from non-magnetic materials such as sand. Magnetism, demonstrated through various experiments with magnets and iron filings, illustrates the properties of magnetic fields and how they can be visualized. Static electricity experiments also show similar attractive effects with charged objects.
Step-by-step explanation:
To separate a mixture of paper clips and sand, magnetic separation is an effective method. Joe can use a magnet to attract the paper clips, which are typically made from a ferromagnetic material. This works because the iron in the paper clips is attracted to the magnet, while the sand, composed of non-magnetic materials, remains unaffected. After separation, the paper clips will adhere to the magnet, and the sand can be discarded or collected separately.
In an illustrative experiment, after rubbing a paper clip with a magnet, the magnetized paper clip can attract another paper clip due to the induced magnetism. Similarly, rubbing the magnet along a metal object such as a knitting needle will magnetize the object, which can then attract the paper clips. This demonstrates magnetism in action.
The patterns formed by iron filings in the presence of a magnetic field enable us to visualize the magnetic field lines. Different arrangements of bar magnets will produce distinctive patterns due to the differences in how magnetic fields interact, whether they are attracting or repelling each other.
During the process of magnetizing objects, particularly with iron or ferromagnetic materials, repeated stroking with a magnet aligns the domains within the material, enhancing its magnetic properties.
Finally, in an experiment involving static electricity, running a comb through hair and then bringing it close to small pieces of paper results in the paper being attracted to the comb. This is due to the static charge acquired by the comb, demonstrating an effect similar to magnetism, but instead, driven by electric charges.