SNC 1D1 – Physics Unit Date: _______________________ The Electrostatic Series How to Predict a Charge In the previous lesson, you saw a balloon become electrostatically charged by rubbing it against hair. To explain this we determined that electrons can move from one object to another when rubbed together. This begs the question… How do you know which object gains electrons and which object loses electrons? Every material has its own specific affinity for electrons. Through experiments, scientists have created a list that ranks common materials in order of how strongly they attract electrons. This list is called the Electrostatic Series Tendency to Relative Material GAIN electrons Charge Acetate Glass Wool Fur, human hair Nylon Silk Cotton Polyethylene (plastic) Carbon, copper, nickel Ebonite Rubber Platinum, gold When two objects are rubbed together: the one closer to the top of this series will _________ electrons and become _________ the one closer to the bottom will ________ electrons and become _________ If the following objects were rubbed together, what charge would they have? Materials Charge Materials Charge (a) glass (c) ebonite rod cotton (b) copper nylon wool (d) human hair plastic comb Activity: Attract or Repel! Instructions: 1. Complete all of your predictions using the electrostatic series BEFORE conducting the experiment. 1. Obtain a watch glass, two small pieces of plasticene or tape and an ebonite rod (with fur). 2. Charge the ebonite rod with fur, then attach it to the center of the watch glass using the plasticene or tape. Charged object Plasticene or tape Watch glass 3. Charge a second ebonite rod with fur. Bring it near the charged rod on the watch glass without touching it. 4. Record the interaction between the objects in the data table blow. 5. Repeat step 3 using a glass rod charged with plastic then with acetate charged with cotton. 6. Repeat steps 1-5, first using a glass rod and then using acetate on the watch glass. 7. Repeat to determine the charge of vinly rubbed with cotton and a plastic comb rubbed with felt. Predictions: Using the Electrostatic Series, what were the charges for each charged object: a) Ebonite Rod _______________ b) Glass Rod - ________________ c) Acetate - __________________ Fur - __________________ Plastic - ________________ Cotton - __________________ Based on your answers, place a + or – next to each object in your chart in the space provided. Charged Object on Watch Glass Charged Object in Hand Ebonite Rod ( Prediction Ebonite Rod ( ) Glass Rod ( ) Acetate ( ) ) Observation Glass Rod ( Prediction ) Observation Vinyl with cotton Comb with felt Charge of vinyl : _____________ Charge of comb : ______________