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.
LETTUCE. The common lettuce of the garden (Lactuca sativa crispa) is a tall, leafy, annual herb with a milky juice. At first the stem is very short and the foliage densely clustered near the ground, but later in the season a flower stalk, 2 to 4 feet high, appears.arly Growth. --Root development in lettuce takes place rapidly. When conditions for growth are very favorable, lateral branches begin to appear on the first 1 to 1.5 inches of taproot only 6 days after the seed is planted and when the cotyledons alone have unfolded.