Presentation on theme: "Foundations of Physical Science Workshop: Electric Circuits."— Presentation transcript:
Foundations of Physical Science Workshop: Electric Circuits
Electric Circuits CPO Science
Key Questions What flow of understanding provides the necessary foundation for an understanding of electricity? What kinds of electric circuits can you build? How does electricity behave?
Light the Bulb! What needs to happen to get the bulb to light?
Parts of our Circuits Kit Wooden Board Wires of various lengths On/Off switches Bulbs and holder Resistors – fixed and variable
Build a simple Circuit Place the bulb in a socket Use one D cell Make the bulb light! Add a switch to conserve D cell energy Use your finger to trace the path of electricity from one terminal of the D cell to the other terminal
Parts of a Circuit Wire Bulb Battery Switch Symbols used for Diagramming
Lets build on this… Add a second D cell to your circuit, right next to the first. Be sure to match up positive terminal with negative terminal Do you notice any difference? Add a second light bulb to the circuit, keeping only one pathway for electricity to follow What do you observe now?
Another way to light two bulbs Keep two D cells in the circuit Wire up the 2 light bulbs so that there are two branches or pathways for electricity to follow What differences do you observe?
Can you explain why the bulbs in a parallel circuit are brighter?
Resistance and Current Inverse Relationship
Voltage The amount of potential energy that each unit of charge has
Review V = voltage, measured in volts I = current, measured in amperes, or amp R = resistance, measured in Ohms, symbol
Using the Multimeter to measure Voltage Battery by itself Battery in a circuit
Using the Multimeter to measure Current Multimeter completes the circuit Current in a circuit
Analyze Circuits 1 bulb2 bulbs in series 2 bulbs in parallel Total voltage available Voltage across each bulb Total current at terminal Current through each bulb
Why are parallel bulbs brighter? 1 bulb2 bulbs in series 2 bulbs in parallel Total voltage available 2.8 V Voltage across each bulb 2.8 V1.4 V2.8 V Total current at terminal.12 A.10 A0.24 A Current through each bulb.12 A.10 A0.12 A
How are they Related? How does changing resistance affect current? How does changing voltage affect current? Investigation Ohms Law Investigating Ohms Law
Current decreases when resistance is increased How does changing resistance affect current?
Voltage/Current = Resistance How does changing voltage affect current?
Rise/Run = Slope Voltage/Current = Resistance
If two of the quantities involved are known, the third can be determined mathematically Ohms Law I = V/R V = IR R = V/I
Basic Circuit Diagrams Series Circuit Parallel Circuit
Are They Related? Can we measure these values in a circuit? As we measure these values, do they change in relation to one another
Using the Multimeter to measure Resistance Resistance of a bulb A measure of conductivity