Let's see the power: Imaging electricity

Abstract

Electricity is around us, not only with the advent of electrical equipment and appliances that about every home, but also in our surrounding in the form of lightning. However this nature of electricity make it difficult for students to appreciate at the same time to create a model on how electricity works.
Hans Oersted in the late 1800 stumbled on the significant discovery that the compass needle moved whenever it was placed on a live wire (Science and Technology IV, 1992). This was one of the significant indicator that electricity moves in a single direction.
However, students were not yet fully aware of the concrete fact how electricity can be modeled easily and visualized by merely using compass and light bulbs to lessen the strain and misconceptions. Until recently during the early 1990's a new curriculum in learning electricity was born, making it student-friendly, and creating an active learning environment, without even requiring any prior knowledge with electricity. This is known as CASTLE.
The word CASTLE is actually an acronym for Capacitor Aided System for Teaching and Learning Electricity. This Curriculum was initially develop by Professor Melvin S. Schoenberg of Smith College. One of the prominent strengths of the Curriculum is the integration of several approaches such as Predict, Observe and Explain, offers visually representation of electricity using bulbs and compass, stimulate model building, testing, criticism and refinement − the central activity of scientific inquiry, allows a qualitative conception of electrical potential and the skills to employ it effectively in circuits and electrostatics, requires no prior knowledge of mechanics or electricity and the best of all its vocabulary was appropriate as an introductory college physics course, secondary physics and even as suited for physical science classes.
The workshop will adapt the first section of the CASTLE student handbook which is suited to secondary high school physics teachers and students. Group does the laboratory activity with maybe three to five members. Each group will be given a set of components which includes a compass and two 3-volt bulbs already mounted on an improvised socket, six alligator clips with wires, and a 3-volt battery. The bulb and compass will serve as the indicator of the electricity. Other materials needed for the activity are the activity worksheet, fixed resistors, 3V-power source and additional connecting wires. The procedure to follow in constructing the circuits is provided in an activity sheet that also includes guide questions.
The lesson starts with sharing of experiences with electricity. Then students are asked how do they verify the existence of electricity around them. A review of the previously learned concept follows. At this stage, the students are expected to know already the basic facts about as follows: Conductor and insulators are important materials in a circuit. The students are also expected to know already the relationship of electricity and magnetism.
After the recall of the prerequisite concepts, the activity is presented. Materials are distributed and a pre-laboratory discussion is conducted. After the activity, students are asked to report their observations to the whole class. They need to explain the effects of changing the battery orientation to the direction of the compass needle.