This activity leads students to the knowledge they will need to construct their headlamp that uses LEDs as a light source. Determine the amount of resistance provided by a resistor by examining its coloured bands. Ohm constructed wires of many different lengths and thicknesses. Today, we simply call these devices resistors because all they do is resist the flow of current. He discovered that for each resistor, no matter what potential difference he applied, the resistance was the same.
Resistors are very important in circuits.
They are used to control current or potential difference in a circuit. In this activity, students will examine the coloured bands on a variety of resistors and use the chart provided to determine their resistance. The second part of the activity involves incorporating the resistors into a simple circuit and using an ammeter to determine the effect that they have on the amount of current flowing through the circuit. Working in groups of two or three, examine a variety of resistors. Look for the colour bands as shown in this diagram.