Answer :
Final answer:
The instrument known as a 'sweet potato' is the ocarina, a wind instrument that can be made from metal, earthenware, or plastic and is known for its sweet potato-like shape.
Explanation:
The musical instrument that is made of hollow metal, earthenware, or plastic and is also referred to as a "sweet potato" is the ocarina. Despite the inclusion of the hammered dulcimer in the background information, it is not commonly known as the "sweet potato". The ocarina is a simple wind instrument with a history that spans various cultures and times. Its shape, often rounded or elongated with a tapered mouthpiece, resembles the vegetable sweet potato, thus giving rise to its nickname. Originally made from clay or ceramics, modern ocarinas can also be found in metal and plastic versions. The instrument produces sound when the musician blows into the mouthpiece, directing air through the internal chambers and over the holes, which can be covered or opened to change pitch.
Originally from South America, the sweet potato or 'Nuala has a significant presence in Polynesian culture, which highlights the ocarina's playful moniker. The ocarina is versatile and capable of producing a wide range of melodies and harmonies, making it a beloved instrument in various contexts, from folk music to contemporary compositions.