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.
One of two major kinds of lettuce (the other being crisphead), butter lettuce's silken leaves grow in softly folding heads. Two popular varieties of butter lettuce are Boston and Bibb; both have a delicate flavor and range from pale green to medium green.Great in salads, especially with creamy dressings, its pretty cupped leaves also make a good bed for other foods.wo popular varieties of butter lettuce are Boston and Bibb; both have a delicate flavor and range from pale green to medium green. Great in salads, especially with creamy dressings, its pretty cupped leaves also make a good bed for other foods.