#### Purposes

• To explore the nature of an electrical circuit
• To explore working variations of a basic circuit
• To determine whether a given material is a conductor or an insulator.

#### Introduction

An electrical cell consists of a single chemical potential energy system with a single positive and negative electrode.

Multiple cells are called a battery. A car battery has six cells. A flashlight usually has two to three cells. Although in everyday English we often say, "This flashlight has three batteries," in truth the flashlight has a single battery of three cells.

In electricity we often use abstract symbols to make drawing diagrams simpler. Some of the objects and symbols are shown below. The object is on the left, the symbol is to its right.

Pictures Corresponding Symbols
 A cell (A bulb is a resistance)

Note that bulbs are considered resistors (or resistances). Diagrams consisting only of symbols are called schematic diagrams.

#### I. Light up the night

Each group should have a cell, a bulb, and a wire. Use the cell and wire to light the bulb.

1. Draw a picture of the circuit that lit the bulb.
2. Make a schematic diagram of the circuit using only the symbols.

Questions to consider:  Does it matter where on the bulb the wires or cell contact the bulb in order to light up the bulb?
If the location of contact(s) matters, indicate the critical locations on the drawing on the right.

#### II. Explore the endless possibilities

Obtain another cell and some more pieces of wire. Find as many arrangements of the cells, wires, and bulbs that cause the bulb to light as possible. Try using both cells.

1. Draw five different arrangements that the group found would light the bulb. Write a note next to a diagram if the arrangement produced a brighter light than other arrangements.
2. Try to make schematic diagrams of the five circuits.

#### III. Conductivity

Determine what materials conduct electricity by testing for conductivity with the cell, bulb, and wires. Label those that conduct electricity as a conductor and those that do not conduct electricity as an insulator.

Is the brightness of the bulb related to the ability of the material to conduct electricity? The relative ability to conduct electricity is termed conductivity. Rate the conductivity for the materials test.

Some materials will be provided, others can be found around the laboratory.

material Conductor
or Insulator
Conductivity:
good/poor/none
material Conductor
or Insulator
Conductivity:
good/poor/none
aluminum ____________ ____________ gold ____________ ____________
basalt ____________ ____________ iron ____________ ____________
brass ____________ ____________ lead ____________ ____________
concrete ____________ ____________ plastic ____________ ____________
copper ____________ ____________ quartz ____________ ____________
coral ____________ ____________ steel ____________ ____________
glass ____________ ____________ wood ____________ ____________
graphite ____________ ____________ zinc ____________ ____________

#### Homework

1. What is your College email address?
2. Does air conduct electricity?
3. Use the Internet to find out how lightning travels through the air. Write up a paragraph including details on the voltage, amperage (current), and power found in lightning.

Recommended places to start Internet searches: