Lab 9 Charge Carriers.pdf
Lab 9 –Charge Carriers:PurposeStudents will attempt to determine the sign of electric charge carriers.TheoryThere was a time when it was not clear whether charge carriers were all positive, all negative, or a mix of both. It was known that they had to be some-how universal to all matter, but there seemed to be two kinds. Chemistry was revealing that acids could break down substances, so using electricity to put them back together yields an answer.Preferred Procedure1.Find a tiny medicine cup or jar that is just big enough to fit a 9-volt battery.2.Put a shiny penny inside it. Modern pennies (post-1982) havezinccores, but that won’t be a problem here.3.Add 1 teaspoon (5ml) of vinegar and ½ teaspoon of hydrogen peroxide.4.Wait 5 hours forthe liquid to turn a deepblue due to dissolved copperions. Waiting longer mayreplace it with a clear color of zinc, which won’t help.5.Remove the penny and stick a 9 volt battery into the fluid, electrodes-down.6.Count to 100, remove the battery, and look forbluish copper compoundson one terminal.Notewhich oneit is.7.Dry the battery with tissue, dump the fluid down the sink, and wash it.Alterative Procedure (Fewer Resources)1.Get a shiny penny and nickel.Again, the penny’s year does not matter.2.Put a drop of vinegar or lemon juice on the nickel and set the pennyon top.3.Wait 5 hours.4.Separate the coins and look for anoff-coloreddeposit on one due to the other. Note which coin got the deposit.AnalysisAcid tries to dissolve any metal, but some are easier to break down. Charge is the missing piece of the metal, so the sign of the charges in electricity is the same as that of the terminalwhere the coating formsdo to being rebuilt.If the alternative procedure was the one performed, the penny/nickelstack wasa weak battery. The nickelis themore reactive metal;it isthe negative terminal. Ironically, the same acid that makes the battery run is a medium to plate out materialon one terminal.Please answer the following using a complete sentenceor twoin a text-only reply in Canvas for this lab:1.What is sign on electrical charges based on the observed results? Please be honest here. Yes, it’s the 21stcentury and everyone has heard of electrons, but herd-behavior in the sciences isa huge problem and far more commonthan anyone likes to admit. Answer by what was observed, not by whatwas expected.Labs seldom work perfectly.Figure 9:Dry off the terminals when done.