Presentation on theme: "Day 27 : 9-26-11 Topic: Battery Objective : How do Batteries Work Starter: Recall from your last lab-What 2 electrodes produced the highest voltage?"— Presentation transcript:
Day 27 : 9-26-11 Topic: Battery Objective : How do Batteries Work Starter: Recall from your last lab-What 2 electrodes produced the highest voltage?
Jigsaw -How Batteries Work Your teacher will assign your sections in the reading. Your group will read, discuss and write down on a whiteboard 3-4 facts per the reading. You will present your facts to the class. Everyone will record the information in their notebook.
History Galvani and Animal Electricity (1791) Frog’s leg contracted when connected to static electricity machine Thought frog was source of electric charge and that wires just completed circuit Volta – skeptical of “life force” Thought frog was just a detection device Knew he had to replace frog with man- made device
The Wet Battery The unit of voltage, VOLTS, is named after Alessandro Volta
A battery must have… Two electrodes – two rods or plates of different metals - electrodes A solution in which charged ions can travel – electrolyte A container to hold the electrolyte Sometimes, other metal caps are attached to the electrodes - terminals
Chemical Reactions Occur in a Battery Some metals – copper, gold, lead give up electrons easily Other metals – zinc, aluminum take up electrons easily Charge is transported from one electrode to the other via a suitable ion from an acid or alkali
What a Battery does A battery does not produce charge. It separates + and - charge through chemical reactions and places them on the electrodes. This separation of charge produces a voltage between the terminals.
New NiMH rechargables – used in cell phones and laptops The new rechargable batteries use nickel as the positive electrode and a hydrogen- absorbing metal alloy as the negative electrode Similar to old Ni-Cd – but the hydrogen produced in cell is absorbed by the negative electrode To recharge - the hydrogen ion is removed and put back into the electrolyte by sending current in the opposite direction
Resources… Check you reading links in the CD www.energizer.comwww.energizer.com – has a learning center with a lot of resources