Learning goal: to understand the nature of electric fields and how to draw field lines. electric field lines are a tool used to visualize electric fields. a field line is drawn beginning at a positive charge and ending at a negative charge. field lines may also appear from the edge of a picture or disappear at the edge of the picture. such lines are said to begin or end at infinity. the field lines are directed so that the electric field at any point is tangent to the field line at that point.