Final answer:
Magnetic and electric fields can be demonstrated using iron filings to visualize magnetic fields or observing the paths of charged particles within an electric field. Option 3 and Option 4 do not pertain to the demonstration of these fields.
Step-by-step explanation:
Magnetic and electric fields can be demonstrated in various ways. Option 1, using iron filings and a bar magnet, is a classic method to visualize a magnetic field. When iron filings are sprinkled around a magnet, they align with the magnetic field lines, creating a visible pattern that represents the magnetic field. Another method, as mentioned in Option 2, is observing the behavior of charged particles within an electric field. Charged particles will move in specific paths when subjected to an electric field, which can show the direction and strength of the field. In contrast, Option 3, measuring temperature changes in a magnetic field, is not a typical demonstration of magnetic or electric fields, nor is Option 4, studying the behavior of sound waves in a vacuum, as sound waves are not related to electromagnetic fields.