In this lab students measure the resistance of various twinkle lights; individually at first and then in combination. They learn how to set up a multimeter as an ohmmeter and to use it for this purpose. Students demonstrate that resistance is cumulative when placed in series. Extension ideas have students measure the resistance of a few lights connected in parallel where they can see that the resistance of the lights drops dramatically. This activity gives experience with series circuits and begins to introduce the idea of parallel circuits. Students are asked to draw a simple circuit diagram showing their setup. 
 
Concepts Addressed
♦ When lights are placed in series, their resistance adds
♦ Resistance is measured using an ohmmeter or multimeter
♦ When placed in series; two lights have twice the resistance of one and so on
♦ When lights are placed in series, their brightness dims 
 
Materials Needed
multimeter, 3+ twinkle lights, 2 alligator clips
 
Time Required This lab takes about 40 mins. 
 
Student Sheets • Scaffolded writing prompts & lab reporting