This kit is designed for student inquiry and discovery, and the instructional guide emphasizes that understanding the concepts should precede calculations. The investigations are related to the basic concepts: open and closed circuits, series circuits, parallel circuits, and combination circuits. These investigations will then engage students to meet challenges and compare the circuits to their existing knowledge of home circuits. Finally, they will be introduced to the concepts of voltage, resistance, and electrical current. Includes - 1 Knife Switch, 3 Bulb Sockets with Connectors, 3 D-Cell Battery Holders, 2 Connector Posts, 10 Miniature Lamps - 2.5 v, 10 Alligator Leads (6"), 10 Alligator Leads (16”), and 1 Magnetic Receptive Mat (24” x 16.5”). Please Note: The Miniature Digital Ammeter and Miniature Digital Voltmeter are not included in this kit.