Conductors and Insulators. In a conductor, electric current can flow freely, in an insulator it cannot. Metals such as copper typify conductors, while most non-metallic solids are said to be good insulators, having extremely high resistance to the flow of charge through them.onductors and Insulators. In a conductor, electric current can flow freely, in an insulator it cannot. Metals such as copper typify conductors, while most non-metallic solids are said to be good insulators, having extremely high resistance to the flow of charge through them.
Butterhead lettuce. A type of head lettuce whose botanical name is Lactuca sativa var. heirloom. Two common types are Boston and bibb lettuce. Have small, round, loosely formed heads with soft, buttery-textured leaves ranging from pale green on the outer leaves to pale yellow-green on the inner leaves.
There are five groups of lettuce categorized by head formation or leaf type. Each of these lettuce varieties offers a unique flavor and texture, and growing different types of lettuce will be a surefire way to generate interest in eating a healthy diet.Letâs learn more about the different lettuce types.risphead lettuce, more commonly known as iceberg, has a tight head of crisp leaves. Often found in the local salad bar and a virtual staple in the delicious BLT, it is actually one of the more difficult lettuce varieties to grow.