- What is a charge?
- a cell with less elections than protons (positively charged) or a cell with more electrons than protons (negatively charged)
- Who do charges transfer?
- touch: friction
- **like charges repel, opposite charges attract**
- when charges transfer, only electrons move
- Affinity
- cells are either "electron loving" or "electron giving"
- meaning that positively charged cells with less electrons tend to give their electrons away or negatively charged cells with more electrons tend to keep their electrons
- different materials are naturally positive like human hair, wool, and air
- different materials are also naturally negative like rubber, tape, and polyester
- Voltage
- electric potential that is attractive and repulsive; a field that surrounds charged objects
- voltage is to electricity as height is to gravitational potential energy
- electric potential energy (Ue) is the charge times the voltage.. this is what gives the Ipad juice
- the higher the voltage, the more charge, the greater the Ue
Real World Connection:
A Lithium-ion battery is supposed to last 10 hours of use before needing to charge. The battery has a high power density that gives you a long battery life in a light package. When the Ipad is plugged into a charger which is plugged into a wall outlet, electrons are flowing. We use this "mountain" analogy to describe voltage and the charge's path. Objects with a positive charge give their electrons away and "run down the mountain." Objects with a negative charge "run up the mountain" to gain more electrons. The cycle continues when charging the Ipad. The negative charges in the battery run uphill and the positive charges run downhill.
http://www.apple.com/batteries/
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| Ipad Battery |
