In order for the light bulbs to light, there must be direct connections from one battery terminal to the metal side of the bulb and from the metal bottom of the bulb to the other terminal. Review the concepts of potential difference, current and resistance. Electrons flow continuously in a closed circuit. Repeat step 1 with the bulb placed inside a holder. Have the students note which two parts of the bulb the holder makes contact with.
Contact is made with the metal side and the metal bottom of the bulb.
Using one battery, light as many bulbs in as many holders as possible. Sketch each arrangement, noting the ones that work. Compare results among the different student groups. Ask the students which arrangements made the most bulbs glow. When more than one bulb is introduced into a circuit, the possible arrangements include both series and parallel circuits as well as various combinations of the two.