Transcript Slide 1
Ohm’s law describes the relationship of current, voltage, and resistance Terminology ______________: is a combination of electrochemical cells connected together ________________________________: converts chemical energy into electrical energy stored in charges. There is a separation of charges. ____________: the ability to do work ________________: energy that a moving object has because of its motion ________________: the energy stored in an object _________________________: the electrical energy stored in a battery is called this because the electrons have stored energy and the ability to do work after they leave the battery ___________________________________: The amount of electric potential energy per one coulomb of charge The unit for measuring potential difference is the ________(___) ______________: is a device that measures the amount of potential difference (_________) between two locations of charge separation. Comparing Potential Energy and Potential Difference When you climb a set of stairs your body has done work. The work done is called ____________________ The more mass moved up the stairs the more potential energy. Think of potential difference in a battery as being like the height of the stairs. The amount of charge separated in a battery is like the mass moved up the stairs. Electric Circuit _______________: a complete pathway that allows electrons to flow. _________________: described as building up at the negative terminal of the cell/battery which then flows from this terminal as negative charges repel one another. Battery has two terminals (ends) called ____________. Usually two different metals _____________: the electrodes are placed in this which can conduct electricity. A reaction occurs between the electrodes and the electrolytes, leaving __________ on one electrode and taking ____________ from another. One electrode is _______ and the other is left ______. The opposite charge on each electrode means that there is a ________________(voltage) between the two electrodes. Parts of an electric circuit _______________: any device that changes electrical energy into other forms of energy. Ex: _____________ ______________: a device that can turn the circuit on or off by closing or opening the circuit Ex.__________ _____________: the source of electrical energy Ex. ___ _______________: the wire through which electric current flows. The energy is provided at the source and then “used” by the different parts of the circuit (_____________________________________________) Energy around a circuit __________________: the continuous flow of charge in a complete circuit. Electrons are ______________from the _______ end of the battery along a circuit and end up on the positive terminal of the battery _______________: the amount of charge passing a point in a conductor every second __________ (__): the SI unit used to measure current. The rate of flow of electric charge. _____________: device used to measure current Voltage vs. Current Analogy: Two identical busses, identical routes leave a school (the battery). One has more students than the other. The speed of the busses can be the same (current) but when they reach the park the bus with more students will have more energy (voltage) Static vs. Current Electricity _______ use static electricity to run an electrical device Static electricity is a charge that remains ___________ Current electricity is the __________________of charge Circuit Symbols ammeter resistor Create circuit diagrams Website: www.andythelwell.com/blobz/guide.html Activity 8-3C: Circuit Diagrams with Resistors _______________: the property of any material that slows down the flow of electrons and converts electrical energy into other forms of energy. Ex: In high resistance wire in light bulbs, the energy is converted to ___________________ _________________________: the ratio of the voltage to the current. _______(___): the SI unit for electrical resistance Analogy: running on a sandy beach versus running in knee high water. Easier to run on beach just as it is easier for electricity to flow through some materials than others Task Activity 8-3A page 271 (factors affecting resistance) Factors affecting Resistance in a wire Factors that affect Resistance 1. _________________- Copper offers less resistance than nichrome 2. _______________________- The thinner the wire, the greater the resistance 3. _______________________- The longer the wire, the greater the resistance (coiled tungsten wire) 4. _________________- The greater the temperature, the greater the resistance Relationship between voltage, current and resistance Ohm’s Law: I = V R V = ___________, I = _________, R = ____________ The more ____________ in a circuit the less _____________flowing The more _________ in a circuit, the more _________ For example: more batteries or volts the greater the current Ohm’s Law calculations Page 273, practice problems. Use the triangle method. V I R Potential difference and Current Interactive websites to demonstrate how one affects the other www.article19.com/shockwave/oz.htm Phet.colorado.edu/simulations/sims.php?sim=Circuit_C onstruction_Kit_DC_Only Core Lab Resistors and Ohm’s Law