Water and ice move around inside the cloud after forced up by warm air currents The particles in the cloud become charged. Then the charges separate (positive moves up, negative move down). A build - up of positive charge on the ground is attracted to the negative charge in the bottom of the cloud. The positive charge from the ground connects with the negative charge from the clouds and a spark of lightning strikes. Interesting Insulators and conductors: Dryer sheets release positively - charged particles to balance out loose electrons. This means there will be less electrons moving from one shirt to another and less attraction (because they’re more positive and not attracted to other positives). Electricity and Electric Circuit s: Four parts of an electric circui t: Battery (source of electrical energy) Light Bulb (electrical load)
Switch (Control device) Connecting wires (electrical conductor) Drawing schematic diagrams: - Battery - Connecting wires - Open switch - Closed Switch - Light bulb - Ammeter - Voltmeter Open and closed circuits: An open circuit mean the current cannot pass through to the positive end. A closed circuit means it is a complete circuit and the current can flow to the positive end. Static and Current Electricity: Static Electricity is when a charge on a substance that stays in 1 place. Current electricity is an amount of charge that passes a point in a conducting wire every second of movement/flow of charge. Voltage: The electric charges flow into the circuit from the negative ter minal. Unit: Volts Symbol: V Series Circuit: In a series circuit, if yo
have 2 lights in series, and bags of pretzels (batteries) were placed one after another, you’d gain a pretzel at each bag. The voltage would be divided. There is more than one light thus, you need to divide the voltage so you have the same amount per load . Parallel Circuit: In a parallel circuit, if there were 2 lights in parallel, and the bags of pretzels were placed one after another, you’d gain a pretzel at each bag. The voltage would be equal. In a parallel, you only take one path. That means you only pass one light bulb. So, you don’t need to divide voltage. Equation for Voltage: V = I x R Example: If the current was 10 amps, and the resistance was 2 ohms, what would the voltage be? I = 10 A. R = 2 ohms V = ? V = I x R V = 10 A x 2 ohms V= 20 V The vo ltage would be 20 V. Electrochemical cells: Primary cell: cannot be recharged and need to be replaced 2 types of primary cells: What makes these 2 primary cells different? Secondary cell: they can be recharged and reused numerous ties befre being recycled Batteries/cells in Series and Parallel: What happens to voltage when we connect batteries in series? - Voltage is divided What happens to voltage when we connect batteries in parallel?
- Voltage is equal Advantages of battery connected in series? - doubles voltage per load - current stays the same Advantages of battery connected in parallel? - equal voltage - doubling current Electric Current: Symbol = I Unit: Amperes Current in parallel: - current is divided; more than one path you can take - in the pretzel experiment, you had more than one path to take so, the current will double Current in series - current stays the same; only one path to take - in the pretzel experiment, you only had one path so everyone followed the same path (the c urrent is equal) Equation for Current: I = V ÷ R
Example: If you had 90 V and a resistance of 9 ohms, what would the current be?
- Fall '10
- Electric charge