Week 3: Circuits October 2nd, 2015 Katie Hellier IRIS Science Academy

Last Week Review of charge Coulomb’s Law Current (Units: Ampere (A)) What types are there? Intro to Voltage

Circuits What is a circuit? What do you need to complete it? How do we measure it? Battery Load + -

Circuits Components Source (battery) Conductor (wire) Load (resistor) Switch Characteristics Current (I) Voltage (V) Resistance (R) Source Resistor + - Switch

Video Explaining an Electric Circuit

Voltage (Potential Difference) The difference in electrical potential energy per unit charge Units: Volts (V) = J/C

Resistance What does it mean to resist? What’s the difference between a 100W bulb and a 200W bulb? Same Voltage 200W bulb has thicker wires – less resistance  Higher current can flow! P = IV Power – Units: Watts (W)

Resistors Electrical energy turns into heat Light bulbs create heat and light! Power is the amount of energy “lost” per second Ohm’s Law – voltage and current are proportional  Resistance! Units (Ω)

Phet – Ohm’s Law s-law/latest/ohms-law_en.html

Parallel vs. Series What do they mean? What are the benefits?

Video Types of Electric Circuits

Diodes What do they do? Current can only flow one direction How do they work?

Super Conductors Not all conductors created equal Most conductors “good” conductors Lose energy based on temperature Some materials reach zero resistance when cooled to very low T  Super conductor!

Lab – Robot Cards Supplies: Card, LED, conductive paint, battery Draw out your circuit Create your card Don’t forget to check the direction of your LED!