Final answer:
A compass is a navigational tool that aligns its magnetized needle with the Earth's magnetic field to indicate direction. To make a makeshift compass, magnetize a needle with a bar magnet, attach it to a cork and float it in water. Compasses are also essential for understanding and visualizing magnetic fields in experiments.
Step-by-step explanation:
The four types of compasses described in TC 3-25.26 are not specified in the provided context; however, a compass is a navigational instrument used for finding directions. It has a magnetized needle that can freely rotate on a pivot, aligning itself with the Earth's magnetic field. To make a simple compass with a bar magnet, a needle, a cork, and a bowl full of water, you would magnetize the needle by rubbing it against the bar magnet, then insert it through a small piece of cork. Float this assembly on water and it will align with the Earth's magnetic field, pointing towards magnetic north.
Compasses are vital in navigation and for understanding magnetic fields. They are commonly used to demonstrate how magnetic fields work and to map them out in experiments, as they align with magnetic field lines. This is shown by observing needle compasses placed in external magnetic fields creating a visual representation of the direction and shape of these fields.